diff --git a/src/main/java/net/onrc/onos/core/topology/Device.java b/src/main/java/net/onrc/onos/core/topology/Device.java
index 25a27be..48035b3 100644
--- a/src/main/java/net/onrc/onos/core/topology/Device.java
+++ b/src/main/java/net/onrc/onos/core/topology/Device.java
@@ -7,12 +7,11 @@
 
 /**
  * Interface of Device Object exposed to the "NB" read-only Topology.
- *
+ * <p/>
  * TODO What a Device Object represent is unclear at the moment.
- *
+ * <p/>
  * Everything returned by these interfaces must be either Unmodifiable view,
  * immutable object, or a copy of the original "SB" In-memory Topology.
- *
  */
 public interface Device {
     /**
@@ -31,7 +30,7 @@
 
     /**
      * Get the device attachment points.
-     *
+     * <p/>
      * Add requirement for Iteration order? Latest observed port first.
      *
      * @return the device attachment points.
@@ -40,7 +39,7 @@
 
     /**
      * Get the device last seen time.
-     *
+     * <p/>
      * TODO: what is the time definition?
      *
      * @return the device last seen time.
diff --git a/src/main/java/net/onrc/onos/core/topology/DeviceEvent.java b/src/main/java/net/onrc/onos/core/topology/DeviceEvent.java
index f7331a0..48d50e4 100644
--- a/src/main/java/net/onrc/onos/core/topology/DeviceEvent.java
+++ b/src/main/java/net/onrc/onos/core/topology/DeviceEvent.java
@@ -12,16 +12,15 @@
 
 /**
  * Self-contained Device event(s) Object
- *
+ * <p/>
  * Device event differ from other events.
  * Device Event represent add/remove of attachmentPoint or ipAddress.
  * Not add/remove of the DeviceObject itself.
- *
+ * <p/>
  * Multiple attachmentPoints can be specified to batch events into 1 object.
  * Each should be treated as independent events.
- *
+ * <p/>
  * TODO: We probably want common base class/interface for Self-Contained Event Object
- *
  */
 public class DeviceEvent {
     private final MACAddress mac;
@@ -34,24 +33,24 @@
      */
     @Deprecated
     public DeviceEvent() {
-	mac = null;
+        mac = null;
     }
 
     public DeviceEvent(MACAddress mac) {
-	if (mac == null) {
-	    throw new IllegalArgumentException("Device mac cannot be null");
-	}
-	this.mac = mac;
-	this.attachmentPoints = new LinkedList<>();
-	this.ipAddresses = new HashSet<>();
+        if (mac == null) {
+            throw new IllegalArgumentException("Device mac cannot be null");
+        }
+        this.mac = mac;
+        this.attachmentPoints = new LinkedList<>();
+        this.ipAddresses = new HashSet<>();
     }
 
     public MACAddress getMac() {
-	return mac;
+        return mac;
     }
 
     public List<SwitchPort> getAttachmentPoints() {
-	return attachmentPoints;
+        return attachmentPoints;
     }
 
     public Set<InetAddress> getIpAddresses() {
@@ -59,46 +58,46 @@
     }
 
     public void setAttachmentPoints(List<SwitchPort> attachmentPoints) {
-	this.attachmentPoints = attachmentPoints;
+        this.attachmentPoints = attachmentPoints;
     }
 
     public void addAttachmentPoint(SwitchPort attachmentPoint) {
-	// may need to maintain uniqness
-	this.attachmentPoints.add(0, attachmentPoint);
+        // may need to maintain uniqness
+        this.attachmentPoints.add(0, attachmentPoint);
     }
 
 
     public boolean addIpAddress(InetAddress addr) {
-	return this.ipAddresses.add(addr);
+        return this.ipAddresses.add(addr);
     }
 
     public boolean removeIpAddress(InetAddress addr) {
-	return this.ipAddresses.remove(addr);
+        return this.ipAddresses.remove(addr);
     }
 
     @Override
     public String toString() {
-	return "[DeviceEvent " + mac + " attachmentPoints:" + attachmentPoints + " ipAddr:" + ipAddresses + "]";
+        return "[DeviceEvent " + mac + " attachmentPoints:" + attachmentPoints + " ipAddr:" + ipAddresses + "]";
     }
 
     // Assuming mac is unique cluster-wide
     public static ByteBuffer getDeviceID(final byte[] mac) {
-	return (ByteBuffer) ByteBuffer.allocate(2 + mac.length).putChar('D').put(mac).flip();
+        return (ByteBuffer) ByteBuffer.allocate(2 + mac.length).putChar('D').put(mac).flip();
     }
 
     public byte[] getID() {
-	return getDeviceID(mac.toBytes()).array();
+        return getDeviceID(mac.toBytes()).array();
     }
 
     public ByteBuffer getIDasByteBuffer() {
-	return getDeviceID(mac.toBytes());
+        return getDeviceID(mac.toBytes());
     }
 
-	public long getLastSeenTime() {
-		return lastSeenTime;
-	}
+    public long getLastSeenTime() {
+        return lastSeenTime;
+    }
 
-	public void setLastSeenTime(long lastSeenTime) {
-		this.lastSeenTime = lastSeenTime;
-	}
+    public void setLastSeenTime(long lastSeenTime) {
+        this.lastSeenTime = lastSeenTime;
+    }
 }
diff --git a/src/main/java/net/onrc/onos/core/topology/DeviceImpl.java b/src/main/java/net/onrc/onos/core/topology/DeviceImpl.java
index 5b96e08..6a4f16b 100644
--- a/src/main/java/net/onrc/onos/core/topology/DeviceImpl.java
+++ b/src/main/java/net/onrc/onos/core/topology/DeviceImpl.java
@@ -20,71 +20,75 @@
     private long lastSeenTime;
 
     public DeviceImpl(NetworkGraph graph, MACAddress mac) {
-		super(graph);
-		this.macAddr = mac;
-		this.attachmentPoints = new LinkedList<>();
-		this.ipAddresses = new HashSet<>();
+        super(graph);
+        this.macAddr = mac;
+        this.attachmentPoints = new LinkedList<>();
+        this.ipAddresses = new HashSet<>();
     }
 
     @Override
     public MACAddress getMacAddress() {
-    	return this.macAddr;
+        return this.macAddr;
     }
 
     @Override
     public Collection<InetAddress> getIpAddress() {
-    	return Collections.unmodifiableSet(ipAddresses);
+        return Collections.unmodifiableSet(ipAddresses);
     }
 
     @Override
     public Iterable<Port> getAttachmentPoints() {
-    	return Collections.unmodifiableList(this.attachmentPoints);
+        return Collections.unmodifiableList(this.attachmentPoints);
     }
 
     @Override
     public long getLastSeenTime() {
-    	return lastSeenTime;
+        return lastSeenTime;
     }
 
     @Override
     public String toString() {
-    	return macAddr.toString();
+        return macAddr.toString();
     }
-    
+
     void setLastSeenTime(long lastSeenTime) {
-    	this.lastSeenTime = lastSeenTime;
+        this.lastSeenTime = lastSeenTime;
     }
 
     /**
      * Only {@link TopologyManager} should use this method
+     *
      * @param p
      */
     void addAttachmentPoint(Port p) {
-    	this.attachmentPoints.remove(p);
-    	this.attachmentPoints.addFirst(p);
+        this.attachmentPoints.remove(p);
+        this.attachmentPoints.addFirst(p);
     }
 
     /**
      * Only {@link TopologyManager} should use this method
+     *
      * @param p
      */
     boolean removeAttachmentPoint(Port p) {
-    	return this.attachmentPoints.remove(p);
+        return this.attachmentPoints.remove(p);
     }
 
     /**
      * Only {@link TopologyManager} should use this method
+     *
      * @param p
      */
     boolean addIpAddress(InetAddress addr) {
-    	return this.ipAddresses.add(addr);
+        return this.ipAddresses.add(addr);
     }
 
     /**
      * Only {@link TopologyManager} should use this method
+     *
      * @param p
      */
     boolean removeIpAddress(InetAddress addr) {
-    	return this.ipAddresses.remove(addr);
+        return this.ipAddresses.remove(addr);
     }
 }
diff --git a/src/main/java/net/onrc/onos/core/topology/INetworkGraphListener.java b/src/main/java/net/onrc/onos/core/topology/INetworkGraphListener.java
index c64b126..9e53222 100644
--- a/src/main/java/net/onrc/onos/core/topology/INetworkGraphListener.java
+++ b/src/main/java/net/onrc/onos/core/topology/INetworkGraphListener.java
@@ -9,36 +9,36 @@
 public interface INetworkGraphListener {
     /**
      * Network Graph events.
-     *
+     * <p/>
      * The recommended ordering rules for applying/processing the events is:
-     *    (a) Process "added" events before "removed" events.
-     *    (b) The ordering of the "added" events should be:
-     *          addedSwitchEvents, addedPortEvents, addedLinkEvents,
-     *          addedDeviceEvents
-     *        The above ordering guarantees that adding a port for example
-     *        will be processed after the corresponding switch itself is added.
-     *    (c) The ordering of the "removed" events should be:
-     *          removedDeviceEvents, removedLinkEvents, removedPortEvents,
-     *          removedSwitchEvents
-     *      The above ordering guarantees that removing a port for example
-     *      will be processed before the corresponding switch itself is
-     *      removed.
+     * (a) Process "added" events before "removed" events.
+     * (b) The ordering of the "added" events should be:
+     * addedSwitchEvents, addedPortEvents, addedLinkEvents,
+     * addedDeviceEvents
+     * The above ordering guarantees that adding a port for example
+     * will be processed after the corresponding switch itself is added.
+     * (c) The ordering of the "removed" events should be:
+     * removedDeviceEvents, removedLinkEvents, removedPortEvents,
+     * removedSwitchEvents
+     * The above ordering guarantees that removing a port for example
+     * will be processed before the corresponding switch itself is
+     * removed.
      *
-     * @param addedSwitchEvents the Added Switch Events.
+     * @param addedSwitchEvents   the Added Switch Events.
      * @param removedSwitchEvents the Removed Switch Events.
-     * @param addedPortEvents the Added Port Events.
-     * @param removedPortEvents the Removed Port Events.
-     * @param addedLinkEvents the Added Link Events.
-     * @param removedLinkEvents the Removed Link Events.
-     * @param addedDeviceEvents the Added Device Events.
+     * @param addedPortEvents     the Added Port Events.
+     * @param removedPortEvents   the Removed Port Events.
+     * @param addedLinkEvents     the Added Link Events.
+     * @param removedLinkEvents   the Removed Link Events.
+     * @param addedDeviceEvents   the Added Device Events.
      * @param removedDeviceEvents the Removed Device Events.
      */
     public void networkGraphEvents(Collection<SwitchEvent> addedSwitchEvents,
-				   Collection<SwitchEvent> removedSwitchEvents,
-				   Collection<PortEvent> addedPortEvents,
-				   Collection<PortEvent> removedPortEvents,
-				   Collection<LinkEvent> addedLinkEvents,
-				   Collection<LinkEvent> removedLinkEvents,
-				   Collection<DeviceEvent> addedDeviceEvents,
-				   Collection<DeviceEvent> removedDeviceEvents);
+                                   Collection<SwitchEvent> removedSwitchEvents,
+                                   Collection<PortEvent> addedPortEvents,
+                                   Collection<PortEvent> removedPortEvents,
+                                   Collection<LinkEvent> addedLinkEvents,
+                                   Collection<LinkEvent> removedLinkEvents,
+                                   Collection<DeviceEvent> addedDeviceEvents,
+                                   Collection<DeviceEvent> removedDeviceEvents);
 }
diff --git a/src/main/java/net/onrc/onos/core/topology/INetworkGraphService.java b/src/main/java/net/onrc/onos/core/topology/INetworkGraphService.java
index 9d4cb3a..18eb785 100644
--- a/src/main/java/net/onrc/onos/core/topology/INetworkGraphService.java
+++ b/src/main/java/net/onrc/onos/core/topology/INetworkGraphService.java
@@ -6,13 +6,15 @@
  * Interface for providing the Network Graph Service to other modules.
  */
 public interface INetworkGraphService extends IFloodlightService {
-	/**
-	 * Allows a module to get a reference to the global network graph object.
-	 * @return
-	 */
+    /**
+     * Allows a module to get a reference to the global network graph object.
+     *
+     * @return
+     */
     public NetworkGraph getNetworkGraph();
 
     public void registerNetworkGraphListener(INetworkGraphListener listener);
+
     public void deregisterNetworkGraphListener(INetworkGraphListener listener);
 
     /**
@@ -20,6 +22,7 @@
      * the network graph.
      * TODO Figure out how to hide the southbound interface from
      * applications/modules that shouldn't touch it
+     *
      * @return
      */
     public NetworkGraphDiscoveryInterface getNetworkGraphDiscoveryInterface();
diff --git a/src/main/java/net/onrc/onos/core/topology/Link.java b/src/main/java/net/onrc/onos/core/topology/Link.java
index f73bccf..2acf7dc 100644
--- a/src/main/java/net/onrc/onos/core/topology/Link.java
+++ b/src/main/java/net/onrc/onos/core/topology/Link.java
@@ -2,10 +2,9 @@
 
 /**
  * Interface of Link Object exposed to the "NB" read-only Topology.
- *
+ * <p/>
  * Everything returned by these interfaces must be either Unmodifiable view,
  * immutable object, or a copy of the original "SB" In-memory Topology.
- *
  */
 public interface Link {
     /**
@@ -38,7 +37,7 @@
 
     /**
      * Get the last seen time for the link.
-     *
+     * <p/>
      * TODO: Not implemented yet.
      * TODO: what is the time definition?
      *
@@ -48,7 +47,7 @@
 
     /**
      * Get the link cost.
-     *
+     * <p/>
      * TODO: What is the unit?
      *
      * @param return the link cost.
@@ -57,7 +56,7 @@
 
     /**
      * Get the link capacity.
-     *
+     * <p/>
      * TODO: What is the unit?
      *
      * @return the link capacity.
diff --git a/src/main/java/net/onrc/onos/core/topology/LinkEvent.java b/src/main/java/net/onrc/onos/core/topology/LinkEvent.java
index bf43155..7434ad9 100644
--- a/src/main/java/net/onrc/onos/core/topology/LinkEvent.java
+++ b/src/main/java/net/onrc/onos/core/topology/LinkEvent.java
@@ -6,9 +6,8 @@
 
 /**
  * Self-contained Link event Object
- *
+ * <p/>
  * TODO: We probably want common base class/interface for Self-Contained Event Object
- *
  */
 public class LinkEvent {
     protected final SwitchPort src;
@@ -19,83 +18,83 @@
      */
     @Deprecated
     public LinkEvent() {
-	src = null;
-	dst = null;
+        src = null;
+        dst = null;
     }
 
     public LinkEvent(Long src_dpid, Long src_port_no, Long dst_dpid,
-	    Long dst_port_no) {
-	src = new SwitchPort(src_dpid, src_port_no);
-	dst = new SwitchPort(dst_dpid, dst_port_no);
+                     Long dst_port_no) {
+        src = new SwitchPort(src_dpid, src_port_no);
+        dst = new SwitchPort(dst_dpid, dst_port_no);
     }
 
     public LinkEvent(Link link) {
-	src = new SwitchPort(link.getSrcSwitch().getDpid(),
-		link.getSrcPort().getNumber());
-	dst = new SwitchPort(link.getDstSwitch().getDpid(),
-		link.getDstPort().getNumber());
+        src = new SwitchPort(link.getSrcSwitch().getDpid(),
+                link.getSrcPort().getNumber());
+        dst = new SwitchPort(link.getDstSwitch().getDpid(),
+                link.getDstPort().getNumber());
     }
 
     public SwitchPort getSrc() {
-	return src;
+        return src;
     }
 
     public SwitchPort getDst() {
-	return dst;
+        return dst;
     }
 
     @Override
     public String toString() {
-	return "[LinkEvent " + src + "->" + dst + "]";
+        return "[LinkEvent " + src + "->" + dst + "]";
     }
 
     public static final int LINKID_BYTES = 2 + PortEvent.PORTID_BYTES * 2;
 
     public static ByteBuffer getLinkID(Long src_dpid, Long src_port_no,
-	    Long dst_dpid, Long dst_port_no) {
-	return (ByteBuffer) ByteBuffer.allocate(LinkEvent.LINKID_BYTES).putChar('L')
-		.put(PortEvent.getPortID(src_dpid, src_port_no))
-		.put(PortEvent.getPortID(dst_dpid, dst_port_no)).flip();
+                                       Long dst_dpid, Long dst_port_no) {
+        return (ByteBuffer) ByteBuffer.allocate(LinkEvent.LINKID_BYTES).putChar('L')
+                .put(PortEvent.getPortID(src_dpid, src_port_no))
+                .put(PortEvent.getPortID(dst_dpid, dst_port_no)).flip();
     }
 
     public byte[] getID() {
-	return getLinkID(src.getDpid(), src.getNumber(),
-		dst.getDpid(), dst.getNumber()).array();
+        return getLinkID(src.getDpid(), src.getNumber(),
+                dst.getDpid(), dst.getNumber()).array();
     }
 
     public ByteBuffer getIDasByteBuffer() {
-	return getLinkID(src.getDpid(), src.getNumber(),
-		dst.getDpid(), dst.getNumber());
+        return getLinkID(src.getDpid(), src.getNumber(),
+                dst.getDpid(), dst.getNumber());
     }
 
     @Override
     public int hashCode() {
-	final int prime = 31;
-	int result = 1;
-	result = prime * result + ((dst == null) ? 0 : dst.hashCode());
-	result = prime * result + ((src == null) ? 0 : src.hashCode());
-	return result;
+        final int prime = 31;
+        int result = 1;
+        result = prime * result + ((dst == null) ? 0 : dst.hashCode());
+        result = prime * result + ((src == null) ? 0 : src.hashCode());
+        return result;
     }
 
     @Override
     public boolean equals(Object obj) {
-	if (this == obj)
-	    return true;
-	if (obj == null)
-	    return false;
-	if (getClass() != obj.getClass())
-	    return false;
-	LinkEvent other = (LinkEvent) obj;
-	if (dst == null) {
-	    if (other.dst != null)
-		return false;
-	} else if (!dst.equals(other.dst))
-	    return false;
-	if (src == null) {
-	    if (other.src != null)
-		return false;
-	} else if (!src.equals(other.src))
-	    return false;
-	return true;
+        if (this == obj)
+            return true;
+        if (obj == null)
+            return false;
+        if (getClass() != obj.getClass())
+            return false;
+        LinkEvent other = (LinkEvent) obj;
+        if (dst == null) {
+            if (other.dst != null)
+                return false;
+        } else if (!dst.equals(other.dst))
+            return false;
+        if (src == null) {
+            if (other.src != null)
+                return false;
+        } else if (!src.equals(other.src))
+            return false;
+        return true;
     }
 }
\ No newline at end of file
diff --git a/src/main/java/net/onrc/onos/core/topology/LinkImpl.java b/src/main/java/net/onrc/onos/core/topology/LinkImpl.java
index d95d4fd..4333e38 100644
--- a/src/main/java/net/onrc/onos/core/topology/LinkImpl.java
+++ b/src/main/java/net/onrc/onos/core/topology/LinkImpl.java
@@ -2,93 +2,94 @@
 
 /**
  * Link Object stored in In-memory Topology.
- *
+ * <p/>
  * TODO REMOVE following design memo: This object itself may hold the DBObject,
  * but this Object itself will not issue any read/write to the DataStore.
  */
 public class LinkImpl extends NetworkGraphObject implements Link {
-	protected Port srcPort;
-	protected Port dstPort;
+    protected Port srcPort;
+    protected Port dstPort;
 
-	protected static final Double DEFAULT_CAPACITY = Double.POSITIVE_INFINITY;
-	protected Double capacity = DEFAULT_CAPACITY;
+    protected static final Double DEFAULT_CAPACITY = Double.POSITIVE_INFINITY;
+    protected Double capacity = DEFAULT_CAPACITY;
 
-	protected static final int DEFAULT_COST = 1;
-	protected int cost = DEFAULT_COST;
+    protected static final int DEFAULT_COST = 1;
+    protected int cost = DEFAULT_COST;
 
-	/**
-	 * Constructor for when a link is read from the database and the Ports
-	 * already exist in the in-memory network graph.
-	 * @param graph
-	 * @param srcPort
-	 * @param dstPort
-	 */
-	public LinkImpl(NetworkGraph graph, Port srcPort, Port dstPort) {
-		super(graph);
-		this.srcPort = srcPort;
-		this.dstPort = dstPort;
-		setToPorts();
-	}
+    /**
+     * Constructor for when a link is read from the database and the Ports
+     * already exist in the in-memory network graph.
+     *
+     * @param graph
+     * @param srcPort
+     * @param dstPort
+     */
+    public LinkImpl(NetworkGraph graph, Port srcPort, Port dstPort) {
+        super(graph);
+        this.srcPort = srcPort;
+        this.dstPort = dstPort;
+        setToPorts();
+    }
 
-	@Override
-	public Switch getSrcSwitch() {
-		return srcPort.getSwitch();
-	}
+    @Override
+    public Switch getSrcSwitch() {
+        return srcPort.getSwitch();
+    }
 
-	@Override
-	public Port getSrcPort() {
-		return srcPort;
-	}
+    @Override
+    public Port getSrcPort() {
+        return srcPort;
+    }
 
-	@Override
-	public Switch getDstSwitch() {
-		return dstPort.getSwitch();
-	}
+    @Override
+    public Switch getDstSwitch() {
+        return dstPort.getSwitch();
+    }
 
-	@Override
-	public Port getDstPort() {
-		return dstPort;
-	}
+    @Override
+    public Port getDstPort() {
+        return dstPort;
+    }
 
-	protected void setToPorts() {
-		((PortImpl)srcPort).setOutgoingLink(this);
-		((PortImpl)dstPort).setIncomingLink(this);
-	}
+    protected void setToPorts() {
+        ((PortImpl) srcPort).setOutgoingLink(this);
+        ((PortImpl) dstPort).setIncomingLink(this);
+    }
 
-	protected void unsetFromPorts() {
-		((PortImpl)srcPort).setOutgoingLink(null);
-		((PortImpl)dstPort).setIncomingLink(null);
-	}
+    protected void unsetFromPorts() {
+        ((PortImpl) srcPort).setOutgoingLink(null);
+        ((PortImpl) dstPort).setIncomingLink(null);
+    }
 
-	@Override
-	public long getLastSeenTime() {
-		// TODO Auto-generated method stub
-		return 0;
-	}
+    @Override
+    public long getLastSeenTime() {
+        // TODO Auto-generated method stub
+        return 0;
+    }
 
-	@Override
-	public int getCost() {
-		return cost;
-	}
+    @Override
+    public int getCost() {
+        return cost;
+    }
 
-	public void setCost(int cost) {
-		this.cost = cost;
-	}
+    public void setCost(int cost) {
+        this.cost = cost;
+    }
 
-	@Override
-	public Double getCapacity() {
-		return capacity;
-	}
+    @Override
+    public Double getCapacity() {
+        return capacity;
+    }
 
-	public void setCapacity(Double capacity) {
-		this.capacity = capacity;
-	}
+    public void setCapacity(Double capacity) {
+        this.capacity = capacity;
+    }
 
-	@Override
-	public String toString() {
-		return String.format("%s --(cap:%f Mbps)--> %s",
-				getSrcPort().toString(),
-				getCapacity(),
-				getDstPort().toString());
-	}
+    @Override
+    public String toString() {
+        return String.format("%s --(cap:%f Mbps)--> %s",
+                getSrcPort().toString(),
+                getCapacity(),
+                getDstPort().toString());
+    }
 }
diff --git a/src/main/java/net/onrc/onos/core/topology/NetworkGraph.java b/src/main/java/net/onrc/onos/core/topology/NetworkGraph.java
index 4e83263..3c583b4 100644
--- a/src/main/java/net/onrc/onos/core/topology/NetworkGraph.java
+++ b/src/main/java/net/onrc/onos/core/topology/NetworkGraph.java
@@ -28,7 +28,7 @@
     /**
      * Get the port on a switch.
      *
-     * @param dpid the switch DPID.
+     * @param dpid   the switch DPID.
      * @param number the switch port number.
      * @return the switch port if found, otherwise null.
      */
@@ -37,7 +37,7 @@
     /**
      * Get the outgoing link for a switch and a port.
      *
-     * @param dpid the switch DPID.
+     * @param dpid   the switch DPID.
      * @param number the switch port number.
      * @return the outgoing link if found, otherwise null.
      */
@@ -47,18 +47,18 @@
      * Get the outgoing link from a switch and a port to another switch and
      * a port.
      *
-     * @param srcDpid the source switch DPID.
+     * @param srcDpid   the source switch DPID.
      * @param srcNumber the source switch port number.
-     * @param dstDpid the destination switch DPID.
+     * @param dstDpid   the destination switch DPID.
      * @param dstNumber the destination switch port number.
      * @return the outgoing link if found, otherwise null.
      */
     public Link getLink(Long srcDpid, Long srcNumber, Long dstDpid,
-			Long dstNumber);
+                        Long dstNumber);
 
     /**
      * Get all links in the network.
-     *
+     * <p/>
      * TODO: Not clear if this method is needed. Remove if not used.
      *
      * @return all links in the network.
@@ -80,15 +80,15 @@
      * @return the network device for the MAC address if found, otherwise null.
      */
     public Device getDeviceByMac(MACAddress address);
-	
+
     /**
-     * Acquire a read lock on the entire topology. The topology will not 
-     * change while readers have the lock. Must be released using 
+     * Acquire a read lock on the entire topology. The topology will not
+     * change while readers have the lock. Must be released using
      * {@link releaseReadLock()}. This method will block until a read lock is
      * available.
      */
     public void acquireReadLock();
-	
+
     /**
      * Release the read lock on the topology.
      */
diff --git a/src/main/java/net/onrc/onos/core/topology/NetworkGraphDatastore.java b/src/main/java/net/onrc/onos/core/topology/NetworkGraphDatastore.java
index 8488297..488915f 100644
--- a/src/main/java/net/onrc/onos/core/topology/NetworkGraphDatastore.java
+++ b/src/main/java/net/onrc/onos/core/topology/NetworkGraphDatastore.java
@@ -26,203 +26,202 @@
  * mutate the graph. This class will maintain the invariants of the network
  * graph. The southbound discovery modules will use this interface to update
  * the network graph as they learn about the state of the network.
- *
+ * <p/>
  * Modification to the Network Map by this module will:
  * 1. Writes to Cluster-wide DataStore.
  * 2. Update ONOS instance In-memory Network Map.
  * 3. Send-out Notification. (TBD)
- *    (XXX: To update other instances In-memory Network Map,
- *          notification should be triggered here.
- *          But if we want to aggregate notification to minimize notification,
- *          It might be better for the caller to trigger notification.)
- *
+ * (XXX: To update other instances In-memory Network Map,
+ * notification should be triggered here.
+ * But if we want to aggregate notification to minimize notification,
+ * It might be better for the caller to trigger notification.)
  */
 public class NetworkGraphDatastore {
-	private static final Logger log = LoggerFactory.getLogger(NetworkGraphDatastore.class);
+    private static final Logger log = LoggerFactory.getLogger(NetworkGraphDatastore.class);
 
-	/**
-	 * Add a switch to the database.
-	 *
-	 * @param sw the switch to add.
-	 * @param portEvents the corresponding switch ports to add.
-	 * @return true on success, otherwise false.
-	 */
-	public boolean addSwitch(SwitchEvent sw,
-				 Collection<PortEvent> portEvents) {
-		log.debug("Adding switch {}", sw);
-		ArrayList<WriteOp> groupOp = new ArrayList<>();
+    /**
+     * Add a switch to the database.
+     *
+     * @param sw         the switch to add.
+     * @param portEvents the corresponding switch ports to add.
+     * @return true on success, otherwise false.
+     */
+    public boolean addSwitch(SwitchEvent sw,
+                             Collection<PortEvent> portEvents) {
+        log.debug("Adding switch {}", sw);
+        ArrayList<WriteOp> groupOp = new ArrayList<>();
 
-		KVSwitch rcSwitch = new KVSwitch(sw.getDpid());
-		rcSwitch.setStatus(KVSwitch.STATUS.ACTIVE);
+        KVSwitch rcSwitch = new KVSwitch(sw.getDpid());
+        rcSwitch.setStatus(KVSwitch.STATUS.ACTIVE);
 
-		IKVClient client = DataStoreClient.getClient();
+        IKVClient client = DataStoreClient.getClient();
 
-		// XXX Is ForceCreating Switch on DB OK here?
-		// If ForceCreating, who ever is calling this method needs
-		// to assure that DPID is unique cluster-wide, etc.
-		groupOp.add(rcSwitch.forceCreateOp(client));
+        // XXX Is ForceCreating Switch on DB OK here?
+        // If ForceCreating, who ever is calling this method needs
+        // to assure that DPID is unique cluster-wide, etc.
+        groupOp.add(rcSwitch.forceCreateOp(client));
 
-		for (PortEvent portEvent : portEvents) {
-			KVPort rcPort = new KVPort(sw.getDpid(), portEvent.getNumber());
-			rcPort.setStatus(KVPort.STATUS.ACTIVE);
+        for (PortEvent portEvent : portEvents) {
+            KVPort rcPort = new KVPort(sw.getDpid(), portEvent.getNumber());
+            rcPort.setStatus(KVPort.STATUS.ACTIVE);
 
-			groupOp.add(rcPort.forceCreateOp(client));
-		}
+            groupOp.add(rcPort.forceCreateOp(client));
+        }
 
-		boolean failed = KVObject.multiWrite(groupOp);
+        boolean failed = KVObject.multiWrite(groupOp);
 
-		if (failed) {
-		    log.error("Adding Switch {} and its ports failed.", sw.getDpid());
-		    for (WriteOp op : groupOp) {
-			log.debug("Operation:{} for {} - Result:{}", op.getOp(), op.getObject(), op.getStatus() );
+        if (failed) {
+            log.error("Adding Switch {} and its ports failed.", sw.getDpid());
+            for (WriteOp op : groupOp) {
+                log.debug("Operation:{} for {} - Result:{}", op.getOp(), op.getObject(), op.getStatus());
 
-			// If we changed the operation from ForceCreate to
-			// Conditional operation (Create/Update) then we should retry here.
-		    }
-		}
-		return !failed;
-	}
+                // If we changed the operation from ForceCreate to
+                // Conditional operation (Create/Update) then we should retry here.
+            }
+        }
+        return !failed;
+    }
 
-	/**
-	 * Update a switch as inactive in the database.
-	 *
-	 * @param sw the switch to update.
-	 * @param portEvents the corresponding switch ports to update.
-	 * @return true on success, otherwise false.
-	 */
-	public boolean deactivateSwitch(SwitchEvent sw,
-					Collection<PortEvent> portEvents) {
-		log.debug("Deactivating switch {}", sw);
-		KVSwitch rcSwitch = new KVSwitch(sw.getDpid());
+    /**
+     * Update a switch as inactive in the database.
+     *
+     * @param sw         the switch to update.
+     * @param portEvents the corresponding switch ports to update.
+     * @return true on success, otherwise false.
+     */
+    public boolean deactivateSwitch(SwitchEvent sw,
+                                    Collection<PortEvent> portEvents) {
+        log.debug("Deactivating switch {}", sw);
+        KVSwitch rcSwitch = new KVSwitch(sw.getDpid());
 
-		IKVClient client = DataStoreClient.getClient();
+        IKVClient client = DataStoreClient.getClient();
 
-		List<WriteOp> groupOp = new ArrayList<>();
-		rcSwitch.setStatus(KVSwitch.STATUS.INACTIVE);
+        List<WriteOp> groupOp = new ArrayList<>();
+        rcSwitch.setStatus(KVSwitch.STATUS.INACTIVE);
 
-		groupOp.add(rcSwitch.forceCreateOp(client));
+        groupOp.add(rcSwitch.forceCreateOp(client));
 
-		for (PortEvent portEvent : portEvents) {
-			KVPort rcPort = new KVPort(sw.getDpid(), portEvent.getNumber());
-			rcPort.setStatus(KVPort.STATUS.INACTIVE);
+        for (PortEvent portEvent : portEvents) {
+            KVPort rcPort = new KVPort(sw.getDpid(), portEvent.getNumber());
+            rcPort.setStatus(KVPort.STATUS.INACTIVE);
 
-			groupOp.add(rcPort.forceCreateOp(client));
-		}
+            groupOp.add(rcPort.forceCreateOp(client));
+        }
 
-		boolean failed = KVObject.multiWrite(groupOp);
+        boolean failed = KVObject.multiWrite(groupOp);
 
-		return !failed;
-	}
+        return !failed;
+    }
 
-	/**
-	 * Add a port to the database.
-	 *
-	 * @param port the port to add.
-	 * @return true on success, otherwise false.
-	 */
-	public boolean addPort(PortEvent port) {
-		log.debug("Adding port {}", port);
+    /**
+     * Add a port to the database.
+     *
+     * @param port the port to add.
+     * @return true on success, otherwise false.
+     */
+    public boolean addPort(PortEvent port) {
+        log.debug("Adding port {}", port);
 
-		KVPort rcPort = new KVPort(port.getDpid(), port.getNumber());
-		rcPort.setStatus(KVPort.STATUS.ACTIVE);
-		rcPort.forceCreate();
-		// TODO add description into KVPort
-		//rcPort.setDescription(port.getDescription());
+        KVPort rcPort = new KVPort(port.getDpid(), port.getNumber());
+        rcPort.setStatus(KVPort.STATUS.ACTIVE);
+        rcPort.forceCreate();
+        // TODO add description into KVPort
+        //rcPort.setDescription(port.getDescription());
 
-		return true;
-	}
+        return true;
+    }
 
-	/**
-	 * Update a port as inactive in the database.
-	 *
-	 * @param port the port to update.
-	 * @return true on success, otherwise false.
-	 */
-	public boolean deactivatePort(PortEvent port) {
-		log.debug("Deactivating port {}", port);
+    /**
+     * Update a port as inactive in the database.
+     *
+     * @param port the port to update.
+     * @return true on success, otherwise false.
+     */
+    public boolean deactivatePort(PortEvent port) {
+        log.debug("Deactivating port {}", port);
 
-		KVPort rcPort = new KVPort(port.getDpid(), port.getNumber());
-		rcPort.setStatus(STATUS.INACTIVE);
+        KVPort rcPort = new KVPort(port.getDpid(), port.getNumber());
+        rcPort.setStatus(STATUS.INACTIVE);
 
-		rcPort.forceCreate();
+        rcPort.forceCreate();
 
-		return true;
-	}
+        return true;
+    }
 
-	/**
-	 * Add a link to the database.
-	 *
-	 * @param link the link to add.
-	 * @return true on success, otherwise false.
-	 */
-	public boolean addLink(LinkEvent link) {
-		log.debug("Adding link {}", link);
+    /**
+     * Add a link to the database.
+     *
+     * @param link the link to add.
+     * @return true on success, otherwise false.
+     */
+    public boolean addLink(LinkEvent link) {
+        log.debug("Adding link {}", link);
 
-		KVLink rcLink = new KVLink(link.getSrc().getDpid(),
-					   link.getSrc().getNumber(),
-					   link.getDst().getDpid(),
-					   link.getDst().getNumber());
+        KVLink rcLink = new KVLink(link.getSrc().getDpid(),
+                link.getSrc().getNumber(),
+                link.getDst().getDpid(),
+                link.getDst().getNumber());
 
-		// XXX This method is called only by discovery,
-		// which means what we are trying to write currently is the truth
-		// so we can force write here
-		//
-		// TODO: We need to check for errors
-		rcLink.setStatus(KVLink.STATUS.ACTIVE);
-		rcLink.forceCreate();
+        // XXX This method is called only by discovery,
+        // which means what we are trying to write currently is the truth
+        // so we can force write here
+        //
+        // TODO: We need to check for errors
+        rcLink.setStatus(KVLink.STATUS.ACTIVE);
+        rcLink.forceCreate();
 
-		return true;					// Success
-	}
+        return true;                    // Success
+    }
 
-	public boolean removeLink(LinkEvent linkEvent) {
-		log.debug("Removing link {}", linkEvent);
+    public boolean removeLink(LinkEvent linkEvent) {
+        log.debug("Removing link {}", linkEvent);
 
-		KVLink rcLink = new KVLink(linkEvent.getSrc().getDpid(), linkEvent.getSrc().getNumber(),
-				linkEvent.getDst().getDpid(), linkEvent.getDst().getNumber());
-		rcLink.forceDelete();
+        KVLink rcLink = new KVLink(linkEvent.getSrc().getDpid(), linkEvent.getSrc().getNumber(),
+                linkEvent.getDst().getDpid(), linkEvent.getDst().getNumber());
+        rcLink.forceDelete();
 
-		return true;
-	}
+        return true;
+    }
 
-	/**
-	 * Add a device to the database.
-	 *
-	 * @param device the device to add.
-	 * @return true on success, otherwise false.
-	 */
-	public boolean addDevice(DeviceEvent device) {
-		log.debug("Adding device into DB. mac {}", device.getMac());
+    /**
+     * Add a device to the database.
+     *
+     * @param device the device to add.
+     * @return true on success, otherwise false.
+     */
+    public boolean addDevice(DeviceEvent device) {
+        log.debug("Adding device into DB. mac {}", device.getMac());
 
-		KVDevice rcDevice = new KVDevice(device.getMac().toBytes());
-		rcDevice.setLastSeenTime(device.getLastSeenTime());
-		
-		for(SwitchPort sp : device.getAttachmentPoints()) {
-			byte[] portId = KVPort.getPortID(sp.getDpid(), sp.getNumber());		
-			rcDevice.addPortId(portId);
-		}
-		
-		for(InetAddress addr : device.getIpAddresses()) {
-			//It assume only one ip on a device now.
-			rcDevice.setIp(InetAddresses.coerceToInteger(addr));	
-		}
+        KVDevice rcDevice = new KVDevice(device.getMac().toBytes());
+        rcDevice.setLastSeenTime(device.getLastSeenTime());
 
-		rcDevice.forceCreate();
-		
-		return true;
-	}
+        for (SwitchPort sp : device.getAttachmentPoints()) {
+            byte[] portId = KVPort.getPortID(sp.getDpid(), sp.getNumber());
+            rcDevice.addPortId(portId);
+        }
 
-	/**
-	 * Remove a device from the database.
-	 *
-	 * @param device the device to remove.
-	 * @return true on success, otherwise false.
-	 */
-	public boolean removeDevice(DeviceEvent device) {
-		log.debug("Removing device into DB. mac {}", device.getMac());
-		
-		KVDevice rcDevice = new KVDevice(device.getMac().toBytes());
-		rcDevice.forceDelete();
-		
-		return true;
-	}
+        for (InetAddress addr : device.getIpAddresses()) {
+            //It assume only one ip on a device now.
+            rcDevice.setIp(InetAddresses.coerceToInteger(addr));
+        }
+
+        rcDevice.forceCreate();
+
+        return true;
+    }
+
+    /**
+     * Remove a device from the database.
+     *
+     * @param device the device to remove.
+     * @return true on success, otherwise false.
+     */
+    public boolean removeDevice(DeviceEvent device) {
+        log.debug("Removing device into DB. mac {}", device.getMac());
+
+        KVDevice rcDevice = new KVDevice(device.getMac().toBytes());
+        rcDevice.forceDelete();
+
+        return true;
+    }
 }
diff --git a/src/main/java/net/onrc/onos/core/topology/NetworkGraphDiscoveryInterface.java b/src/main/java/net/onrc/onos/core/topology/NetworkGraphDiscoveryInterface.java
index 14ef0ea..219417f 100644
--- a/src/main/java/net/onrc/onos/core/topology/NetworkGraphDiscoveryInterface.java
+++ b/src/main/java/net/onrc/onos/core/topology/NetworkGraphDiscoveryInterface.java
@@ -11,10 +11,10 @@
      * Switch discovered event.
      *
      * @param switchEvent the switch event.
-     * @param portEvents the corresponding port events for the switch.
+     * @param portEvents  the corresponding port events for the switch.
      */
     public void putSwitchDiscoveryEvent(SwitchEvent switchEvent,
-					Collection<PortEvent> portEvents);
+                                        Collection<PortEvent> portEvents);
 
     /**
      * Switch removed event.
diff --git a/src/main/java/net/onrc/onos/core/topology/NetworkGraphImpl.java b/src/main/java/net/onrc/onos/core/topology/NetworkGraphImpl.java
index 902ffa6..a60e390 100644
--- a/src/main/java/net/onrc/onos/core/topology/NetworkGraphImpl.java
+++ b/src/main/java/net/onrc/onos/core/topology/NetworkGraphImpl.java
@@ -18,143 +18,143 @@
 import org.slf4j.LoggerFactory;
 
 public class NetworkGraphImpl implements NetworkGraph {
-	@SuppressWarnings("unused")
-	private static final Logger log = LoggerFactory.getLogger(NetworkGraphImpl.class);
+    @SuppressWarnings("unused")
+    private static final Logger log = LoggerFactory.getLogger(NetworkGraphImpl.class);
 
-	// DPID -> Switch
-	private ConcurrentMap<Long, Switch> switches;
+    // DPID -> Switch
+    private ConcurrentMap<Long, Switch> switches;
 
-	private ConcurrentMap<InetAddress, Set<Device>> addr2Device;
-	private ConcurrentMap<MACAddress, Device> mac2Device;
+    private ConcurrentMap<InetAddress, Set<Device>> addr2Device;
+    private ConcurrentMap<MACAddress, Device> mac2Device;
 
-	private ReadWriteLock readWriteLock = new ReentrantReadWriteLock();
-	private Lock readLock = readWriteLock.readLock();
-	// TODO use the write lock after refactor
-	private Lock writeLock = readWriteLock.writeLock();
+    private ReadWriteLock readWriteLock = new ReentrantReadWriteLock();
+    private Lock readLock = readWriteLock.readLock();
+    // TODO use the write lock after refactor
+    private Lock writeLock = readWriteLock.writeLock();
 
-	public NetworkGraphImpl() {
-		// TODO: Does these object need to be stored in Concurrent Collection?
-		switches = new ConcurrentHashMap<>();
-		addr2Device = new ConcurrentHashMap<>();
-		mac2Device = new ConcurrentHashMap<>();
-	}
+    public NetworkGraphImpl() {
+        // TODO: Does these object need to be stored in Concurrent Collection?
+        switches = new ConcurrentHashMap<>();
+        addr2Device = new ConcurrentHashMap<>();
+        mac2Device = new ConcurrentHashMap<>();
+    }
 
-	@Override
-	public Switch getSwitch(Long dpid) {
-		// TODO Check if it is safe to directly return this Object.
-		return switches.get(dpid);
-	}
+    @Override
+    public Switch getSwitch(Long dpid) {
+        // TODO Check if it is safe to directly return this Object.
+        return switches.get(dpid);
+    }
 
-	protected void putSwitch(Switch sw) {
-		switches.put(sw.getDpid(), sw);
-	}
+    protected void putSwitch(Switch sw) {
+        switches.put(sw.getDpid(), sw);
+    }
 
-	protected void removeSwitch(Long dpid) {
-		switches.remove(dpid);
-	}
+    protected void removeSwitch(Long dpid) {
+        switches.remove(dpid);
+    }
 
-	@Override
-	public Iterable<Switch> getSwitches() {
-		// TODO Check if it is safe to directly return this Object.
-		return Collections.unmodifiableCollection(switches.values());
-	}
+    @Override
+    public Iterable<Switch> getSwitches() {
+        // TODO Check if it is safe to directly return this Object.
+        return Collections.unmodifiableCollection(switches.values());
+    }
 
-	@Override
-	public Port getPort(Long dpid, Long number) {
-	    Switch sw = getSwitch(dpid);
-	    if (sw != null) {
-		return sw.getPort(number);
-	    }
-	    return null;
-	}
+    @Override
+    public Port getPort(Long dpid, Long number) {
+        Switch sw = getSwitch(dpid);
+        if (sw != null) {
+            return sw.getPort(number);
+        }
+        return null;
+    }
 
-	@Override
-	public Link getLink(Long dpid, Long number) {
-	    Port srcPort = getPort(dpid, number);
-	    if (srcPort == null)
-		return null;
-	    return srcPort.getOutgoingLink();
-	}
+    @Override
+    public Link getLink(Long dpid, Long number) {
+        Port srcPort = getPort(dpid, number);
+        if (srcPort == null)
+            return null;
+        return srcPort.getOutgoingLink();
+    }
 
-	@Override
-	public Link getLink(Long srcDpid, Long srcNumber, Long dstDpid,
-			    Long dstNumber) {
-	    Link link = getLink(srcDpid, srcNumber);
-	    if (link == null)
-		return null;
-	    if (!link.getDstSwitch().getDpid().equals(dstDpid))
-		return null;
-	    if (!link.getDstPort().getNumber().equals(dstNumber))
-		return null;
-	    return link;
-	}
+    @Override
+    public Link getLink(Long srcDpid, Long srcNumber, Long dstDpid,
+                        Long dstNumber) {
+        Link link = getLink(srcDpid, srcNumber);
+        if (link == null)
+            return null;
+        if (!link.getDstSwitch().getDpid().equals(dstDpid))
+            return null;
+        if (!link.getDstPort().getNumber().equals(dstNumber))
+            return null;
+        return link;
+    }
 
-	@Override
-	public Iterable<Link> getLinks() {
-		List<Link> linklist = new LinkedList<>();
+    @Override
+    public Iterable<Link> getLinks() {
+        List<Link> linklist = new LinkedList<>();
 
-		for (Switch sw : switches.values()) {
-			Iterable<Link> links = sw.getOutgoingLinks();
-			for (Link l : links) {
-				linklist.add(l);
-			}
-		}
-		return linklist;
-	}
+        for (Switch sw : switches.values()) {
+            Iterable<Link> links = sw.getOutgoingLinks();
+            for (Link l : links) {
+                linklist.add(l);
+            }
+        }
+        return linklist;
+    }
 
-	@Override
-	public Iterable<Device> getDevicesByIp(InetAddress ipAddress) {
-		Set<Device> devices = addr2Device.get(ipAddress);
-		if (devices == null) {
-			return Collections.emptySet();
-		}
-		return Collections.unmodifiableCollection(devices);
-	}
+    @Override
+    public Iterable<Device> getDevicesByIp(InetAddress ipAddress) {
+        Set<Device> devices = addr2Device.get(ipAddress);
+        if (devices == null) {
+            return Collections.emptySet();
+        }
+        return Collections.unmodifiableCollection(devices);
+    }
 
-	@Override
-	public Device getDeviceByMac(MACAddress address) {
-		return mac2Device.get(address);
-	}
+    @Override
+    public Device getDeviceByMac(MACAddress address) {
+        return mac2Device.get(address);
+    }
 
-	protected void putDevice(Device device) {
-	    mac2Device.put(device.getMacAddress(), device);
-	    for (InetAddress ipAddr : device.getIpAddress()) {
-		Set<Device> devices = addr2Device.get(ipAddr);
-		if (devices == null) {
-		    devices = new HashSet<>();
-		    addr2Device.put(ipAddr, devices);
-		}
-		devices.add(device);
-	    }
-	}
+    protected void putDevice(Device device) {
+        mac2Device.put(device.getMacAddress(), device);
+        for (InetAddress ipAddr : device.getIpAddress()) {
+            Set<Device> devices = addr2Device.get(ipAddr);
+            if (devices == null) {
+                devices = new HashSet<>();
+                addr2Device.put(ipAddr, devices);
+            }
+            devices.add(device);
+        }
+    }
 
-	protected void removeDevice(Device device) {
-	    mac2Device.remove(device.getMacAddress());
-	    for (InetAddress ipAddr : device.getIpAddress()) {
-		Set<Device> devices = addr2Device.get(ipAddr);
-		if (devices != null) {
-		    devices.remove(device);
-		    if (devices.isEmpty())
-			addr2Device.remove(ipAddr);
-		}
-	    }
-	}
+    protected void removeDevice(Device device) {
+        mac2Device.remove(device.getMacAddress());
+        for (InetAddress ipAddr : device.getIpAddress()) {
+            Set<Device> devices = addr2Device.get(ipAddr);
+            if (devices != null) {
+                devices.remove(device);
+                if (devices.isEmpty())
+                    addr2Device.remove(ipAddr);
+            }
+        }
+    }
 
-	@Override
-	public void acquireReadLock() {
-		readLock.lock();
-	}
+    @Override
+    public void acquireReadLock() {
+        readLock.lock();
+    }
 
-	@Override
-	public void releaseReadLock() {
-		readLock.unlock();
-	}
+    @Override
+    public void releaseReadLock() {
+        readLock.unlock();
+    }
 
-	protected void acquireWriteLock() {
-		writeLock.lock();
-	}
+    protected void acquireWriteLock() {
+        writeLock.lock();
+    }
 
-	protected void releaseWriteLock() {
-		writeLock.unlock();
-	}
+    protected void releaseWriteLock() {
+        writeLock.unlock();
+    }
 }
diff --git a/src/main/java/net/onrc/onos/core/topology/NetworkGraphModule.java b/src/main/java/net/onrc/onos/core/topology/NetworkGraphModule.java
index c693df5..77981d6 100644
--- a/src/main/java/net/onrc/onos/core/topology/NetworkGraphModule.java
+++ b/src/main/java/net/onrc/onos/core/topology/NetworkGraphModule.java
@@ -18,80 +18,80 @@
 
 public class NetworkGraphModule implements IFloodlightModule, INetworkGraphService {
 
-	// This is initialized as a module for now
+    // This is initialized as a module for now
 
-	private TopologyManager topologyManager;
-	//private NetworkGraphDatastore southboundNetworkGraph;
-	private IDatagridService datagridService;
-	private IControllerRegistryService registryService;
+    private TopologyManager topologyManager;
+    //private NetworkGraphDatastore southboundNetworkGraph;
+    private IDatagridService datagridService;
+    private IControllerRegistryService registryService;
 
-	private CopyOnWriteArrayList<INetworkGraphListener> networkGraphListeners;
+    private CopyOnWriteArrayList<INetworkGraphListener> networkGraphListeners;
 
-	private IRestApiService restApi;
+    private IRestApiService restApi;
 
-	@Override
-	public Collection<Class<? extends IFloodlightService>> getModuleServices() {
-		List<Class<? extends IFloodlightService>> services =
-				new ArrayList<Class<? extends IFloodlightService>>();
-		services.add(INetworkGraphService.class);
-		return services;
-	}
+    @Override
+    public Collection<Class<? extends IFloodlightService>> getModuleServices() {
+        List<Class<? extends IFloodlightService>> services =
+                new ArrayList<Class<? extends IFloodlightService>>();
+        services.add(INetworkGraphService.class);
+        return services;
+    }
 
-	@Override
-	public Map<Class<? extends IFloodlightService>, IFloodlightService>
-			getServiceImpls() {
-		Map<Class<? extends IFloodlightService>, IFloodlightService> impls =
-				new HashMap<Class<? extends IFloodlightService>, IFloodlightService>();
-		impls.put(INetworkGraphService.class, this);
-		return impls;
-	}
+    @Override
+    public Map<Class<? extends IFloodlightService>, IFloodlightService>
+    getServiceImpls() {
+        Map<Class<? extends IFloodlightService>, IFloodlightService> impls =
+                new HashMap<Class<? extends IFloodlightService>, IFloodlightService>();
+        impls.put(INetworkGraphService.class, this);
+        return impls;
+    }
 
-	@Override
-	public Collection<Class<? extends IFloodlightService>> getModuleDependencies() {
-		List<Class<? extends IFloodlightService>> dependencies =
-				new ArrayList<Class<? extends IFloodlightService>>();
-		dependencies.add(IDatagridService.class);
-		dependencies.add(IRestApiService.class);
-		dependencies.add(IControllerRegistryService.class);
-		return dependencies;
-	}
+    @Override
+    public Collection<Class<? extends IFloodlightService>> getModuleDependencies() {
+        List<Class<? extends IFloodlightService>> dependencies =
+                new ArrayList<Class<? extends IFloodlightService>>();
+        dependencies.add(IDatagridService.class);
+        dependencies.add(IRestApiService.class);
+        dependencies.add(IControllerRegistryService.class);
+        return dependencies;
+    }
 
-	@Override
-	public void init(FloodlightModuleContext context)
-			throws FloodlightModuleException {
-		restApi = context.getServiceImpl(IRestApiService.class);
-		datagridService = context.getServiceImpl(IDatagridService.class);
-		registryService = context.getServiceImpl(IControllerRegistryService.class);
+    @Override
+    public void init(FloodlightModuleContext context)
+            throws FloodlightModuleException {
+        restApi = context.getServiceImpl(IRestApiService.class);
+        datagridService = context.getServiceImpl(IDatagridService.class);
+        registryService = context.getServiceImpl(IControllerRegistryService.class);
 
-		networkGraphListeners = new CopyOnWriteArrayList<>();
-		topologyManager = new TopologyManager(registryService, networkGraphListeners);
-		//southboundNetworkGraph = new NetworkGraphDatastore(networkGraph);
-	}
+        networkGraphListeners = new CopyOnWriteArrayList<>();
+        topologyManager = new TopologyManager(registryService, networkGraphListeners);
+        //southboundNetworkGraph = new NetworkGraphDatastore(networkGraph);
+    }
 
-	@Override
-	public void startUp(FloodlightModuleContext context) {
-		restApi.addRestletRoutable(new NetworkGraphWebRoutable());
-		topologyManager.startup(datagridService);
-	}
+    @Override
+    public void startUp(FloodlightModuleContext context) {
+        restApi.addRestletRoutable(new NetworkGraphWebRoutable());
+        topologyManager.startup(datagridService);
+    }
 
-	@Override
-	public NetworkGraph getNetworkGraph() {
-		return topologyManager.getNetworkGraph();
-	}
+    @Override
+    public NetworkGraph getNetworkGraph() {
+        return topologyManager.getNetworkGraph();
+    }
 
-	@Override
-	public NetworkGraphDiscoveryInterface getNetworkGraphDiscoveryInterface() {
-		return topologyManager;
-	}
+    @Override
+    public NetworkGraphDiscoveryInterface getNetworkGraphDiscoveryInterface() {
+        return topologyManager;
+    }
 
-	@Override
-	public void registerNetworkGraphListener(INetworkGraphListener listener) {
-	    networkGraphListeners.addIfAbsent(listener);
-	}
+    @Override
+    public void registerNetworkGraphListener(INetworkGraphListener listener) {
+        networkGraphListeners.addIfAbsent(listener);
+    }
 
-	@Override
-	public void deregisterNetworkGraphListener(INetworkGraphListener listener) {
-	    networkGraphListeners.remove(listener);
-	}
+    @Override
+    public void deregisterNetworkGraphListener(INetworkGraphListener listener) {
+        networkGraphListeners.remove(listener);
+    }
 
 }
diff --git a/src/main/java/net/onrc/onos/core/topology/NetworkGraphObject.java b/src/main/java/net/onrc/onos/core/topology/NetworkGraphObject.java
index fde4a44..bef0e11 100644
--- a/src/main/java/net/onrc/onos/core/topology/NetworkGraphObject.java
+++ b/src/main/java/net/onrc/onos/core/topology/NetworkGraphObject.java
@@ -3,10 +3,10 @@
 
 public class NetworkGraphObject {
 
-	protected final NetworkGraph graph;
-	
-	public NetworkGraphObject(NetworkGraph graph) {
-		this.graph = graph;
-	}
+    protected final NetworkGraph graph;
+
+    public NetworkGraphObject(NetworkGraph graph) {
+        this.graph = graph;
+    }
 
 }
diff --git a/src/main/java/net/onrc/onos/core/topology/NetworkGraphPublisher.java b/src/main/java/net/onrc/onos/core/topology/NetworkGraphPublisher.java
index fef71e7..bc72e00 100644
--- a/src/main/java/net/onrc/onos/core/topology/NetworkGraphPublisher.java
+++ b/src/main/java/net/onrc/onos/core/topology/NetworkGraphPublisher.java
@@ -37,13 +37,12 @@
  * The NetworkGraphPublisher subscribes to topology network events from the
  * discovery modules. These events are reformatted and relayed to the topology
  * part of the network graph
- *
  */
 public class NetworkGraphPublisher implements /*IOFSwitchListener,*/
-                                    IOFSwitchPortListener,
-                                    ILinkDiscoveryListener,
-                                    IFloodlightModule,
-                                    IOnosDeviceListener {
+        IOFSwitchPortListener,
+        ILinkDiscoveryListener,
+        IFloodlightModule,
+        IOnosDeviceListener {
     private static final Logger log =
             LoggerFactory.getLogger(NetworkGraphPublisher.class);
 
@@ -96,7 +95,7 @@
                 log.trace("Checking for inactive switches");
             }
             // For each switch check if a controller exists in controller registry
-            for (Switch sw: switches) {
+            for (Switch sw : switches) {
                 try {
                     String controller =
                             registryService.getControllerForSwitch(sw.getDpid());
@@ -115,7 +114,8 @@
          * Second half of the switch cleanup operation. If the registry grants
          * control of a switch, we can be sure no other instance is writing
          * this switch to the network graph, so we can remove it now.
-         * @param dpid the dpid of the switch we requested control for
+         *
+         * @param dpid       the dpid of the switch we requested control for
          * @param hasControl whether we got control or not
          */
         @Override
@@ -139,17 +139,17 @@
                 (long) update.getDstPort());
 
         switch (update.getOperation()) {
-        case LINK_ADDED:
-            networkGraphDiscoveryInterface.putLinkDiscoveryEvent(linkEvent);
-            break;
-        case LINK_UPDATED:
-            // We don't use the LINK_UPDATED event (unsure what it means)
-            break;
-        case LINK_REMOVED:
-            networkGraphDiscoveryInterface.removeLinkDiscoveryEvent(linkEvent);
-            break;
-        default:
-            break;
+            case LINK_ADDED:
+                networkGraphDiscoveryInterface.putLinkDiscoveryEvent(linkEvent);
+                break;
+            case LINK_UPDATED:
+                // We don't use the LINK_UPDATED event (unsure what it means)
+                break;
+            case LINK_REMOVED:
+                networkGraphDiscoveryInterface.removeLinkDiscoveryEvent(linkEvent);
+                break;
+            default:
+                break;
         }
     }
 
@@ -180,7 +180,7 @@
             portEvents.add(new PortEvent(sw.getId(), (long) port.getPortNumber()));
         }
         networkGraphDiscoveryInterface
-        .putSwitchDiscoveryEvent(switchEvent, portEvents);
+                .putSwitchDiscoveryEvent(switchEvent, portEvents);
 
         for (OFPhysicalPort port : sw.getPorts()) {
             // Allow links to be discovered on this port now that it's
@@ -222,7 +222,7 @@
 
     @Override
     public Collection<Class<? extends IFloodlightService>>
-                getModuleDependencies() {
+    getModuleDependencies() {
         Collection<Class<? extends IFloodlightService>> l =
                 new ArrayList<Class<? extends IFloodlightService>>();
         l.add(IFloodlightProviderService.class);
diff --git a/src/main/java/net/onrc/onos/core/topology/Path.java b/src/main/java/net/onrc/onos/core/topology/Path.java
index 1d15fc7..9c5118d 100644
--- a/src/main/java/net/onrc/onos/core/topology/Path.java
+++ b/src/main/java/net/onrc/onos/core/topology/Path.java
@@ -5,20 +5,21 @@
 
 /**
  * Base class for Path representation
+ *
  * @author Toshio Koide (t-koide@onlab.us)
  */
 public class Path extends LinkedList<LinkEvent> {
-	private static final long serialVersionUID = 7127274096495173415L;
+    private static final long serialVersionUID = 7127274096495173415L;
 
-	@Override
-	public String toString() {
-		StringBuilder builder = new StringBuilder();
-		Iterator<LinkEvent> i = this.iterator();
-		while (i.hasNext()) {
-			builder.append(i.next().toString());
-			if (i.hasNext())
-				builder.append(", ");
-		}
-		return builder.toString();
-	}
+    @Override
+    public String toString() {
+        StringBuilder builder = new StringBuilder();
+        Iterator<LinkEvent> i = this.iterator();
+        while (i.hasNext()) {
+            builder.append(i.next().toString());
+            if (i.hasNext())
+                builder.append(", ");
+        }
+        return builder.toString();
+    }
 }
diff --git a/src/main/java/net/onrc/onos/core/topology/Port.java b/src/main/java/net/onrc/onos/core/topology/Port.java
index e9f6bb8..216d4b8 100644
--- a/src/main/java/net/onrc/onos/core/topology/Port.java
+++ b/src/main/java/net/onrc/onos/core/topology/Port.java
@@ -1,24 +1,26 @@
 package net.onrc.onos.core.topology;
 
 
-
 /**
  * Interface of Port Object exposed to the "NB" read-only Topology.
- *
+ * <p/>
  * Everything returned by these interfaces must be either Unmodifiable view,
  * immutable object, or a copy of the original "SB" In-memory Topology.
- *
  */
 public interface Port {
-	public Long getDpid();
-	public Long getNumber();
-	public Long getHardwareAddress();
-	public String getDescription();
+    public Long getDpid();
 
-	public Switch getSwitch();
+    public Long getNumber();
 
-	public Link getOutgoingLink();
-	public Link getIncomingLink();
+    public Long getHardwareAddress();
 
-	public Iterable<Device> getDevices();
+    public String getDescription();
+
+    public Switch getSwitch();
+
+    public Link getOutgoingLink();
+
+    public Link getIncomingLink();
+
+    public Iterable<Device> getDevices();
 }
diff --git a/src/main/java/net/onrc/onos/core/topology/PortEvent.java b/src/main/java/net/onrc/onos/core/topology/PortEvent.java
index 65d0b94..2a18c08 100644
--- a/src/main/java/net/onrc/onos/core/topology/PortEvent.java
+++ b/src/main/java/net/onrc/onos/core/topology/PortEvent.java
@@ -4,23 +4,22 @@
 
 /**
  * Self-contained Port event Object
- *
+ * <p/>
  * TODO: We probably want common base class/interface for Self-Contained Event Object
- *
  */
 public class PortEvent {
     public static class SwitchPort {
-	public final Long dpid;
-	public final Long number;
+        public final Long dpid;
+        public final Long number;
 
-	/**
-	 * Default constructor for Serializer to use.
-	 */
-	@Deprecated
-	public SwitchPort() {
-	    dpid = null;
-	    number = null;
-	}
+        /**
+         * Default constructor for Serializer to use.
+         */
+        @Deprecated
+        public SwitchPort() {
+            dpid = null;
+            number = null;
+        }
 
         public SwitchPort(Long dpid, Long number) {
             this.dpid = dpid;
@@ -46,29 +45,29 @@
             int result = 1;
             result = prime * result + ((dpid == null) ? 0 : dpid.hashCode());
             result = prime * result
-        	    + ((number == null) ? 0 : number.hashCode());
+                    + ((number == null) ? 0 : number.hashCode());
             return result;
         }
 
         @Override
         public boolean equals(Object obj) {
             if (this == obj)
-        	return true;
+                return true;
             if (obj == null)
-        	return false;
+                return false;
             if (getClass() != obj.getClass())
-        	return false;
+                return false;
             SwitchPort other = (SwitchPort) obj;
             if (dpid == null) {
-        	if (other.dpid != null)
-        	    return false;
+                if (other.dpid != null)
+                    return false;
             } else if (!dpid.equals(other.dpid))
-        	return false;
+                return false;
             if (number == null) {
-        	if (other.number != null)
-        	    return false;
+                if (other.number != null)
+                    return false;
             } else if (!number.equals(other.number))
-        	return false;
+                return false;
             return true;
         }
     }
@@ -82,44 +81,44 @@
      */
     @Deprecated
     public PortEvent() {
-	id = null;
+        id = null;
     }
 
     public PortEvent(Long dpid, Long number) {
-	this.id = new SwitchPort(dpid, number);
+        this.id = new SwitchPort(dpid, number);
     }
 
     public Long getDpid() {
-	return id.dpid;
+        return id.dpid;
     }
 
     public Long getNumber() {
-	return id.number;
+        return id.number;
     }
 
     @Override
     public String toString() {
-	return "[PortEvent 0x" + Long.toHexString(id.dpid) + "@" + id.number + "]";
+        return "[PortEvent 0x" + Long.toHexString(id.dpid) + "@" + id.number + "]";
     }
 
     public static final int PORTID_BYTES = SwitchEvent.SWITCHID_BYTES + 2 + 8;
 
     public static ByteBuffer getPortID(Long dpid, Long number) {
-	if (dpid == null) {
-	    throw new IllegalArgumentException("dpid cannot be null");
-	}
-	if (number == null) {
-	    throw new IllegalArgumentException("number cannot be null");
-	}
-	return (ByteBuffer) ByteBuffer.allocate(PortEvent.PORTID_BYTES).putChar('S').putLong(dpid)
-		.putChar('P').putLong(number).flip();
+        if (dpid == null) {
+            throw new IllegalArgumentException("dpid cannot be null");
+        }
+        if (number == null) {
+            throw new IllegalArgumentException("number cannot be null");
+        }
+        return (ByteBuffer) ByteBuffer.allocate(PortEvent.PORTID_BYTES).putChar('S').putLong(dpid)
+                .putChar('P').putLong(number).flip();
     }
 
     public byte[] getID() {
-	return getPortID(getDpid(), getNumber()).array();
+        return getPortID(getDpid(), getNumber()).array();
     }
 
     public ByteBuffer getIDasByteBuffer() {
-	return getPortID(getDpid(), getNumber());
+        return getPortID(getDpid(), getNumber());
     }
 }
diff --git a/src/main/java/net/onrc/onos/core/topology/PortImpl.java b/src/main/java/net/onrc/onos/core/topology/PortImpl.java
index cd7d82b..32646d0 100644
--- a/src/main/java/net/onrc/onos/core/topology/PortImpl.java
+++ b/src/main/java/net/onrc/onos/core/topology/PortImpl.java
@@ -6,108 +6,106 @@
 
 /**
  * Port Object stored in In-memory Topology.
- *
+ * <p/>
  * TODO REMOVE following design memo: This object itself may hold the DBObject,
  * but this Object itself will not issue any read/write to the DataStore.
  */
 public class PortImpl extends NetworkGraphObject implements Port {
 
-	private Switch sw;
+    private Switch sw;
 
-	private Long number;
-	private String description;
+    private Long number;
+    private String description;
 
-	protected Link outgoingLink;
-	protected Link incomingLink;
-	// These needs to be ConcurrentCollecton if allowing Graph to be accessed Concurrently
-	protected Set<Device> devices;
+    protected Link outgoingLink;
+    protected Link incomingLink;
+    // These needs to be ConcurrentCollecton if allowing Graph to be accessed Concurrently
+    protected Set<Device> devices;
 
-	public PortImpl(NetworkGraph graph, Switch parentSwitch, Long number) {
-		super(graph);
-		this.sw = parentSwitch;
-		this.number = number;
-		this.devices = new HashSet<>();
-	}
+    public PortImpl(NetworkGraph graph, Switch parentSwitch, Long number) {
+        super(graph);
+        this.sw = parentSwitch;
+        this.number = number;
+        this.devices = new HashSet<>();
+    }
 
-	@Override
-	public Long getDpid() {
-	    return sw.getDpid();
-	}
+    @Override
+    public Long getDpid() {
+        return sw.getDpid();
+    }
 
-	@Override
-	public Long getNumber() {
-		return number;
-	}
+    @Override
+    public Long getNumber() {
+        return number;
+    }
 
-	@Override
-	public String getDescription() {
-		return description;
-	}
+    @Override
+    public String getDescription() {
+        return description;
+    }
 
-	public void setDescription(String description) {
-		this.description = description;
-	}
+    public void setDescription(String description) {
+        this.description = description;
+    }
 
-	@Override
-	public Long getHardwareAddress() {
-		// TODO Auto-generated method stub
-		return 0L;
-	}
+    @Override
+    public Long getHardwareAddress() {
+        // TODO Auto-generated method stub
+        return 0L;
+    }
 
-	@Override
-	public Switch getSwitch() {
-		return sw;
-	}
+    @Override
+    public Switch getSwitch() {
+        return sw;
+    }
 
-	@Override
-	public Link getOutgoingLink() {
-		return outgoingLink;
-	}
+    @Override
+    public Link getOutgoingLink() {
+        return outgoingLink;
+    }
 
-	@Override
-	public Link getIncomingLink() {
-		return incomingLink;
-	}
+    @Override
+    public Link getIncomingLink() {
+        return incomingLink;
+    }
 
-	@Override
-	public Iterable<Device> getDevices() {
-	    return Collections.unmodifiableSet(this.devices);
-	}
+    @Override
+    public Iterable<Device> getDevices() {
+        return Collections.unmodifiableSet(this.devices);
+    }
 
-	public void setOutgoingLink(Link link) {
-		outgoingLink = link;
-	}
+    public void setOutgoingLink(Link link) {
+        outgoingLink = link;
+    }
 
-	public void setIncomingLink(Link link) {
-		incomingLink = link;
-	}
+    public void setIncomingLink(Link link) {
+        incomingLink = link;
+    }
 
-	/**
-	 *
-	 * @param d
-	 * @return true if successfully added
-	 */
-	public boolean addDevice(Device d) {
-	    return this.devices.add(d);
-	}
+    /**
+     * @param d
+     * @return true if successfully added
+     */
+    public boolean addDevice(Device d) {
+        return this.devices.add(d);
+    }
 
-	/**
-	 *
-	 * @param d
-	 * @return true if device existed and was removed
-	 */
-	public boolean removeDevice(Device d) {
-	    return this.devices.remove(d);
-	}
+    /**
+     * @param d
+     * @return true if device existed and was removed
+     */
+    public boolean removeDevice(Device d) {
+        return this.devices.remove(d);
+    }
 
-	public void removeAllDevice() {
-	    this.devices.clear();
-	}
+    public void removeAllDevice() {
+        this.devices.clear();
+    }
 
-	@Override
-	public String toString() {
-		return String.format("%d:%d",
-				getSwitch().getDpid(),
-				getNumber());
-	}
+    @Override
+    public String toString() {
+        return String.format("%d:%d",
+                getSwitch().getDpid(),
+                getNumber());
+    }
 }
diff --git a/src/main/java/net/onrc/onos/core/topology/Switch.java b/src/main/java/net/onrc/onos/core/topology/Switch.java
index 0b97dfa..d9796be 100644
--- a/src/main/java/net/onrc/onos/core/topology/Switch.java
+++ b/src/main/java/net/onrc/onos/core/topology/Switch.java
@@ -4,28 +4,28 @@
 
 /**
  * Interface of Switch Object exposed to the "NB" read-only Topology.
- *
+ * <p/>
  * Everything returned by these interfaces must be either Unmodifiable view,
  * immutable object, or a copy of the original "SB" In-memory Topology.
- *
  */
 public interface Switch {
-	public Long getDpid();
+    public Long getDpid();
 
-	public Collection<Port> getPorts();
+    public Collection<Port> getPorts();
 
-	public Port getPort(Long number);
+    public Port getPort(Long number);
 
 
-	// Graph traversal API
-	// XXX What is the Definition of neighbor? Link exist in both direction or one-way is sufficient to be a neighbor, etc.
-	public Iterable<Switch> getNeighbors();
+    // Graph traversal API
+    // XXX What is the Definition of neighbor? Link exist in both direction or one-way is sufficient to be a neighbor, etc.
+    public Iterable<Switch> getNeighbors();
 
-	public Iterable<Link> getOutgoingLinks();
-	public Iterable<Link> getIncomingLinks();
+    public Iterable<Link> getOutgoingLinks();
 
-	public Link getLinkToNeighbor(Long dpid);
+    public Iterable<Link> getIncomingLinks();
 
-	// XXX Iterable or Collection?
-	public Collection<Device> getDevices();
+    public Link getLinkToNeighbor(Long dpid);
+
+    // XXX Iterable or Collection?
+    public Collection<Device> getDevices();
 }
diff --git a/src/main/java/net/onrc/onos/core/topology/SwitchEvent.java b/src/main/java/net/onrc/onos/core/topology/SwitchEvent.java
index b36eba2..7ed65d8 100644
--- a/src/main/java/net/onrc/onos/core/topology/SwitchEvent.java
+++ b/src/main/java/net/onrc/onos/core/topology/SwitchEvent.java
@@ -4,9 +4,8 @@
 
 /**
  * Self-contained Switch Object
- *
+ * <p/>
  * TODO: We probably want common base class/interface for Self-Contained Event Object
- *
  */
 public class SwitchEvent {
     protected final Long dpid;
@@ -16,36 +15,36 @@
      */
     @Deprecated
     public SwitchEvent() {
-	dpid = null;
+        dpid = null;
     }
 
     public SwitchEvent(Long dpid) {
-	this.dpid = dpid;
+        this.dpid = dpid;
     }
 
     public Long getDpid() {
-	return dpid;
+        return dpid;
     }
 
     @Override
     public String toString() {
-	return "[SwitchEvent 0x" + Long.toHexString(dpid) + "]";
+        return "[SwitchEvent 0x" + Long.toHexString(dpid) + "]";
     }
 
     public static final int SWITCHID_BYTES = 2 + 8;
 
     public static ByteBuffer getSwitchID(Long dpid) {
-	if (dpid == null) {
-	    throw new IllegalArgumentException("dpid cannot be null");
-	}
-	return (ByteBuffer) ByteBuffer.allocate(SwitchEvent.SWITCHID_BYTES).putChar('S').putLong(dpid).flip();
+        if (dpid == null) {
+            throw new IllegalArgumentException("dpid cannot be null");
+        }
+        return (ByteBuffer) ByteBuffer.allocate(SwitchEvent.SWITCHID_BYTES).putChar('S').putLong(dpid).flip();
     }
 
     public byte[] getID() {
-	return getSwitchID(dpid).array();
+        return getSwitchID(dpid).array();
     }
 
     public ByteBuffer getIDasByteBuffer() {
-	return getSwitchID(dpid);
+        return getSwitchID(dpid);
     }
 }
diff --git a/src/main/java/net/onrc/onos/core/topology/SwitchImpl.java b/src/main/java/net/onrc/onos/core/topology/SwitchImpl.java
index 8a45b76..3fe053c 100644
--- a/src/main/java/net/onrc/onos/core/topology/SwitchImpl.java
+++ b/src/main/java/net/onrc/onos/core/topology/SwitchImpl.java
@@ -12,111 +12,111 @@
 
 /**
  * Switch Object stored in In-memory Topology.
- *
+ * <p/>
  * TODO REMOVE following design memo: This object itself may hold the DBObject,
  * but this Object itself will not issue any read/write to the DataStore.
  */
 public class SwitchImpl extends NetworkGraphObject implements Switch {
 
-	private Long dpid;
-	// These needs to be ConcurrentCollecton if allowing Graph to be accessed Concurrently
-	private final Map<Long, Port> ports;
+    private Long dpid;
+    // These needs to be ConcurrentCollecton if allowing Graph to be accessed Concurrently
+    private final Map<Long, Port> ports;
 
-	public SwitchImpl(NetworkGraph graph, Long dpid) {
-		super(graph);
-		this.dpid = dpid;
-		ports = new HashMap<Long, Port>();
-	}
+    public SwitchImpl(NetworkGraph graph, Long dpid) {
+        super(graph);
+        this.dpid = dpid;
+        ports = new HashMap<Long, Port>();
+    }
 
-	@Override
-	public Long getDpid() {
-		return dpid;
-	}
+    @Override
+    public Long getDpid() {
+        return dpid;
+    }
 
-	@Override
-	public Collection<Port> getPorts() {
-		return Collections.unmodifiableCollection(ports.values());
-	}
+    @Override
+    public Collection<Port> getPorts() {
+        return Collections.unmodifiableCollection(ports.values());
+    }
 
-	@Override
-	public Port getPort(Long number) {
-		return ports.get(number);
-	}
+    @Override
+    public Port getPort(Long number) {
+        return ports.get(number);
+    }
 
-	@Override
-	public Iterable<Switch> getNeighbors() {
-		Set<Switch> neighbors = new HashSet<>();
-		for (Link link : getOutgoingLinks()) {
-		    neighbors.add(link.getDstSwitch());
-		}
-		// XXX should incoming considered neighbor?
-		for (Link link : getIncomingLinks()) {
-		    neighbors.add(link.getSrcSwitch());
-		}
-		return neighbors;
-	}
+    @Override
+    public Iterable<Switch> getNeighbors() {
+        Set<Switch> neighbors = new HashSet<>();
+        for (Link link : getOutgoingLinks()) {
+            neighbors.add(link.getDstSwitch());
+        }
+        // XXX should incoming considered neighbor?
+        for (Link link : getIncomingLinks()) {
+            neighbors.add(link.getSrcSwitch());
+        }
+        return neighbors;
+    }
 
-	@Override
-	public Link getLinkToNeighbor(Long neighborDpid) {
-		for (Link link : getOutgoingLinks()) {
-			if (link.getDstSwitch().getDpid().equals(neighborDpid) ) {
-				return link;
-			}
-		}
-		return null;
-	}
+    @Override
+    public Link getLinkToNeighbor(Long neighborDpid) {
+        for (Link link : getOutgoingLinks()) {
+            if (link.getDstSwitch().getDpid().equals(neighborDpid)) {
+                return link;
+            }
+        }
+        return null;
+    }
 
-	@Override
-	public Collection<Device> getDevices() {
-		// TODO Should switch also store a list of attached devices to avoid
-		// calculating this every time?
-		List<Device> devices = new ArrayList<Device>();
+    @Override
+    public Collection<Device> getDevices() {
+        // TODO Should switch also store a list of attached devices to avoid
+        // calculating this every time?
+        List<Device> devices = new ArrayList<Device>();
 
-		for (Port port : ports.values()) {
-			for (Device device : port.getDevices()) {
-				devices.add(device);
-			}
-		}
+        for (Port port : ports.values()) {
+            for (Device device : port.getDevices()) {
+                devices.add(device);
+            }
+        }
 
-		return devices;
-	}
+        return devices;
+    }
 
-	public void addPort(Port port) {
-		this.ports.put(port.getNumber(), port);
-	}
+    public void addPort(Port port) {
+        this.ports.put(port.getNumber(), port);
+    }
 
-	public Port removePort(Port port) {
-	    Port p = this.ports.remove(port.getNumber());
-	    return p;
-	}
+    public Port removePort(Port port) {
+        Port p = this.ports.remove(port.getNumber());
+        return p;
+    }
 
-	public Port addPort(Long portNumber) {
-		PortImpl port = new PortImpl(graph, this, portNumber);
-		ports.put(port.getNumber(), port);
-		return port;
-	}
+    public Port addPort(Long portNumber) {
+        PortImpl port = new PortImpl(graph, this, portNumber);
+        ports.put(port.getNumber(), port);
+        return port;
+    }
 
-	@Override
-	public Iterable<Link> getOutgoingLinks() {
-		LinkedList<Link> links = new LinkedList<Link>();
-		for (Port port: getPorts()) {
-			Link link = port.getOutgoingLink();
-			if (link != null) {
-				links.add(link);
-			}
-		}
-		return links;
-	}
+    @Override
+    public Iterable<Link> getOutgoingLinks() {
+        LinkedList<Link> links = new LinkedList<Link>();
+        for (Port port : getPorts()) {
+            Link link = port.getOutgoingLink();
+            if (link != null) {
+                links.add(link);
+            }
+        }
+        return links;
+    }
 
-	@Override
-	public Iterable<Link> getIncomingLinks() {
-		LinkedList<Link> links = new LinkedList<Link>();
-		for (Port port: getPorts()) {
-			Link link = port.getIncomingLink();
-			if (link != null) {
-				links.add(link);
-			}
-		}
-		return links;
-	}
+    @Override
+    public Iterable<Link> getIncomingLinks() {
+        LinkedList<Link> links = new LinkedList<Link>();
+        for (Port port : getPorts()) {
+            Link link = port.getIncomingLink();
+            if (link != null) {
+                links.add(link);
+            }
+        }
+        return links;
+    }
 }
diff --git a/src/main/java/net/onrc/onos/core/topology/TopologyEvent.java b/src/main/java/net/onrc/onos/core/topology/TopologyEvent.java
index 84cd5cb..4f3dd20 100644
--- a/src/main/java/net/onrc/onos/core/topology/TopologyEvent.java
+++ b/src/main/java/net/onrc/onos/core/topology/TopologyEvent.java
@@ -2,16 +2,16 @@
 
 /**
  * Self-contained Topology event Object
- *
+ * <p/>
  * TODO: For now the topology event contains one of the following events:
  * Switch, Port, Link, Device. In the future it will contain multiple events
  * in a single transaction.
  */
 public class TopologyEvent {
-    SwitchEvent switchEvent = null;		// Set for Switch event
-    PortEvent portEvent = null;			// Set for Port event
-    LinkEvent linkEvent = null;			// Set for Link event
-    DeviceEvent deviceEvent = null;		// Set for Device event
+    SwitchEvent switchEvent = null;        // Set for Switch event
+    PortEvent portEvent = null;            // Set for Port event
+    LinkEvent linkEvent = null;            // Set for Link event
+    DeviceEvent deviceEvent = null;        // Set for Device event
 
     /**
      * Default constructor.
@@ -25,7 +25,7 @@
      * @param switchEvent the Switch event to use.
      */
     TopologyEvent(SwitchEvent switchEvent) {
-	this.switchEvent = switchEvent;
+        this.switchEvent = switchEvent;
     }
 
     /**
@@ -34,7 +34,7 @@
      * @param portEvent the Port event to use.
      */
     TopologyEvent(PortEvent portEvent) {
-	this.portEvent = portEvent;
+        this.portEvent = portEvent;
     }
 
     /**
@@ -43,7 +43,7 @@
      * @param linkEvent the Link event to use.
      */
     TopologyEvent(LinkEvent linkEvent) {
-	this.linkEvent = linkEvent;
+        this.linkEvent = linkEvent;
     }
 
     /**
@@ -52,7 +52,7 @@
      * @param deviceEvent the Device event to use.
      */
     TopologyEvent(DeviceEvent deviceEvent) {
-	this.deviceEvent = deviceEvent;
+        this.deviceEvent = deviceEvent;
     }
 
     /**
@@ -62,15 +62,15 @@
      */
     @Override
     public String toString() {
-	if (switchEvent != null)
-	    return switchEvent.toString();
-	if (portEvent != null)
-	    return portEvent.toString();
-	if (linkEvent != null)
-	    return linkEvent.toString();
-	if (deviceEvent != null)
-	    return deviceEvent.toString();
-	return "[Empty TopologyEvent]";
+        if (switchEvent != null)
+            return switchEvent.toString();
+        if (portEvent != null)
+            return portEvent.toString();
+        if (linkEvent != null)
+            return linkEvent.toString();
+        if (deviceEvent != null)
+            return deviceEvent.toString();
+        return "[Empty TopologyEvent]";
     }
 
     /**
@@ -79,14 +79,14 @@
      * @return the Topology event ID.
      */
     public byte[] getID() {
-	if (switchEvent != null)
-	    return switchEvent.getID();
-	if (portEvent != null)
-	    return portEvent.getID();
-	if (linkEvent != null)
-	    return linkEvent.getID();
-	if (deviceEvent != null)
-	    return deviceEvent.getID();
-	return null;
+        if (switchEvent != null)
+            return switchEvent.getID();
+        if (portEvent != null)
+            return portEvent.getID();
+        if (linkEvent != null)
+            return linkEvent.getID();
+        if (deviceEvent != null)
+            return deviceEvent.getID();
+        return null;
     }
 }
diff --git a/src/main/java/net/onrc/onos/core/topology/TopologyManager.java b/src/main/java/net/onrc/onos/core/topology/TopologyManager.java
index b12eaae..4788641 100644
--- a/src/main/java/net/onrc/onos/core/topology/TopologyManager.java
+++ b/src/main/java/net/onrc/onos/core/topology/TopologyManager.java
@@ -29,22 +29,21 @@
 
 /**
  * The "NB" read-only Network Map.
- *
+ * <p/>
  * - Maintain Invariant/Relationships between Topology Objects.
- *
+ * <p/>
  * TODO To be synchronized based on TopologyEvent Notification.
- *
+ * <p/>
  * TODO TBD: Caller is expected to maintain parent/child calling order. Parent
  * Object must exist before adding sub component(Add Switch -> Port).
- *
+ * <p/>
  * TODO TBD: This class may delay the requested change to handle event
  * re-ordering. e.g.) Link Add came in, but Switch was not there.
- *
  */
 public class TopologyManager implements NetworkGraphDiscoveryInterface {
 
     private static final Logger log = LoggerFactory
-	    .getLogger(TopologyManager.class);
+            .getLogger(TopologyManager.class);
 
     private IEventChannel<byte[], TopologyEvent> eventChannel;
     public static final String EVENT_CHANNEL_NAME = "onos.topology";
@@ -60,11 +59,11 @@
     // NOTE: Switch Events are not affected by the event reordering.
     //
     private Map<ByteBuffer, PortEvent> reorderedAddedPortEvents =
-	new HashMap<ByteBuffer, PortEvent>();
+            new HashMap<ByteBuffer, PortEvent>();
     private Map<ByteBuffer, LinkEvent> reorderedAddedLinkEvents =
-	new HashMap<ByteBuffer, LinkEvent>();
+            new HashMap<ByteBuffer, LinkEvent>();
     private Map<ByteBuffer, DeviceEvent> reorderedAddedDeviceEvents =
-	new HashMap<ByteBuffer, DeviceEvent>();
+            new HashMap<ByteBuffer, DeviceEvent>();
 
     //
     // Local state for keeping track of locally discovered events so we can
@@ -77,11 +76,11 @@
     //    and Device events.
     //
     private Map<Long, Map<ByteBuffer, PortEvent>> discoveredAddedPortEvents =
-	new HashMap<>();
+            new HashMap<>();
     private Map<Long, Map<ByteBuffer, LinkEvent>> discoveredAddedLinkEvents =
-	new HashMap<>();
+            new HashMap<>();
     private Map<Long, Map<ByteBuffer, DeviceEvent>> discoveredAddedDeviceEvents =
-	new HashMap<>();
+            new HashMap<>();
 
     //
     // Local state for keeping track of the application event notifications
@@ -98,15 +97,15 @@
     /**
      * Constructor.
      *
-     * @param registryService the Registry Service to use.
+     * @param registryService       the Registry Service to use.
      * @param networkGraphListeners the collection of Network Graph Listeners
-     * to use.
+     *                              to use.
      */
     public TopologyManager(IControllerRegistryService registryService,
-			   CopyOnWriteArrayList<INetworkGraphListener> networkGraphListeners) {
-	datastore = new NetworkGraphDatastore();
-	this.registryService = registryService;
-	this.networkGraphListeners = networkGraphListeners;
+                           CopyOnWriteArrayList<INetworkGraphListener> networkGraphListeners) {
+        datastore = new NetworkGraphDatastore();
+        this.registryService = registryService;
+        this.networkGraphListeners = networkGraphListeners;
     }
 
     /**
@@ -115,247 +114,246 @@
      * @return the Network Graph.
      */
     NetworkGraph getNetworkGraph() {
-	return networkGraph;
+        return networkGraph;
     }
 
     /**
      * Event handler class.
      */
     private class EventHandler extends Thread implements
-	IEventChannelListener<byte[], TopologyEvent> {
-	private BlockingQueue<EventEntry<TopologyEvent>> topologyEvents =
-	    new LinkedBlockingQueue<EventEntry<TopologyEvent>>();
+            IEventChannelListener<byte[], TopologyEvent> {
+        private BlockingQueue<EventEntry<TopologyEvent>> topologyEvents =
+                new LinkedBlockingQueue<EventEntry<TopologyEvent>>();
 
-	/**
-	 * Startup processing.
-	 */
-	private void startup() {
-	    //
-	    // TODO: Read all state from the database:
-	    //
-	    // Collection<EventEntry<TopologyEvent>> collection =
-	    //    readWholeTopologyFromDB();
-	    //
-	    // For now, as a shortcut we read it from the datagrid
-	    //
-	    Collection<TopologyEvent> topologyEvents =
-		eventChannel.getAllEntries();
-	    Collection<EventEntry<TopologyEvent>> collection =
-		new LinkedList<EventEntry<TopologyEvent>>();
+        /**
+         * Startup processing.
+         */
+        private void startup() {
+            //
+            // TODO: Read all state from the database:
+            //
+            // Collection<EventEntry<TopologyEvent>> collection =
+            //    readWholeTopologyFromDB();
+            //
+            // For now, as a shortcut we read it from the datagrid
+            //
+            Collection<TopologyEvent> topologyEvents =
+                    eventChannel.getAllEntries();
+            Collection<EventEntry<TopologyEvent>> collection =
+                    new LinkedList<EventEntry<TopologyEvent>>();
 
-	    for (TopologyEvent topologyEvent : topologyEvents) {
-		EventEntry<TopologyEvent> eventEntry =
-		    new EventEntry<TopologyEvent>(EventEntry.Type.ENTRY_ADD,
-						  topologyEvent);
-		collection.add(eventEntry);
-	    }
-	    processEvents(collection);
-	}
+            for (TopologyEvent topologyEvent : topologyEvents) {
+                EventEntry<TopologyEvent> eventEntry =
+                        new EventEntry<TopologyEvent>(EventEntry.Type.ENTRY_ADD,
+                                topologyEvent);
+                collection.add(eventEntry);
+            }
+            processEvents(collection);
+        }
 
-	/**
-	 * Run the thread.
-	 */
-	@Override
-	public void run() {
-	    Collection<EventEntry<TopologyEvent>> collection =
-		new LinkedList<EventEntry<TopologyEvent>>();
+        /**
+         * Run the thread.
+         */
+        @Override
+        public void run() {
+            Collection<EventEntry<TopologyEvent>> collection =
+                    new LinkedList<EventEntry<TopologyEvent>>();
 
-	    this.setName("TopologyManager.EventHandler " + this.getId());
-	    startup();
+            this.setName("TopologyManager.EventHandler " + this.getId());
+            startup();
 
-	    //
-	    // The main loop
-	    //
-	    try {
-		while (true) {
-		    EventEntry<TopologyEvent> eventEntry = topologyEvents.take();
-		    collection.add(eventEntry);
-		    topologyEvents.drainTo(collection);
+            //
+            // The main loop
+            //
+            try {
+                while (true) {
+                    EventEntry<TopologyEvent> eventEntry = topologyEvents.take();
+                    collection.add(eventEntry);
+                    topologyEvents.drainTo(collection);
 
-		    processEvents(collection);
-		    collection.clear();
-		}
-	    } catch (Exception exception) {
-		log.debug("Exception processing Topology Events: ", exception);
-	    }
-	}
+                    processEvents(collection);
+                    collection.clear();
+                }
+            } catch (Exception exception) {
+                log.debug("Exception processing Topology Events: ", exception);
+            }
+        }
 
-	/**
-	 * Process all topology events.
-	 *
-	 * @param events the events to process.
-	 */
-	private void processEvents(Collection<EventEntry<TopologyEvent>> events) {
-	    // Local state for computing the final set of events
-	    Map<ByteBuffer, SwitchEvent> addedSwitchEvents = new HashMap<>();
-	    Map<ByteBuffer, SwitchEvent> removedSwitchEvents = new HashMap<>();
-	    Map<ByteBuffer, PortEvent> addedPortEvents = new HashMap<>();
-	    Map<ByteBuffer, PortEvent> removedPortEvents = new HashMap<>();
-	    Map<ByteBuffer, LinkEvent> addedLinkEvents = new HashMap<>();
-	    Map<ByteBuffer, LinkEvent> removedLinkEvents = new HashMap<>();
-	    Map<ByteBuffer, DeviceEvent> addedDeviceEvents = new HashMap<>();
-	    Map<ByteBuffer, DeviceEvent> removedDeviceEvents = new HashMap<>();
+        /**
+         * Process all topology events.
+         *
+         * @param events the events to process.
+         */
+        private void processEvents(Collection<EventEntry<TopologyEvent>> events) {
+            // Local state for computing the final set of events
+            Map<ByteBuffer, SwitchEvent> addedSwitchEvents = new HashMap<>();
+            Map<ByteBuffer, SwitchEvent> removedSwitchEvents = new HashMap<>();
+            Map<ByteBuffer, PortEvent> addedPortEvents = new HashMap<>();
+            Map<ByteBuffer, PortEvent> removedPortEvents = new HashMap<>();
+            Map<ByteBuffer, LinkEvent> addedLinkEvents = new HashMap<>();
+            Map<ByteBuffer, LinkEvent> removedLinkEvents = new HashMap<>();
+            Map<ByteBuffer, DeviceEvent> addedDeviceEvents = new HashMap<>();
+            Map<ByteBuffer, DeviceEvent> removedDeviceEvents = new HashMap<>();
 
-	    //
-	    // Classify and suppress matching events
-	    //
-	    for (EventEntry<TopologyEvent> event : events) {
-		TopologyEvent topologyEvent = event.eventData();
-		SwitchEvent switchEvent = topologyEvent.switchEvent;
-		PortEvent portEvent = topologyEvent.portEvent;
-		LinkEvent linkEvent = topologyEvent.linkEvent;
-		DeviceEvent deviceEvent = topologyEvent.deviceEvent;
+            //
+            // Classify and suppress matching events
+            //
+            for (EventEntry<TopologyEvent> event : events) {
+                TopologyEvent topologyEvent = event.eventData();
+                SwitchEvent switchEvent = topologyEvent.switchEvent;
+                PortEvent portEvent = topologyEvent.portEvent;
+                LinkEvent linkEvent = topologyEvent.linkEvent;
+                DeviceEvent deviceEvent = topologyEvent.deviceEvent;
 
-		//
-		// Extract the events
-		//
-		switch (event.eventType()) {
-		case ENTRY_ADD:
-		    log.debug("Topology event ENTRY_ADD: {}", topologyEvent);
-		    if (switchEvent != null) {
-			ByteBuffer id = switchEvent.getIDasByteBuffer();
-			addedSwitchEvents.put(id, switchEvent);
-			removedSwitchEvents.remove(id);
-			// Switch Events are not affected by event reordering
-		    }
-		    if (portEvent != null) {
-			ByteBuffer id = portEvent.getIDasByteBuffer();
-			addedPortEvents.put(id, portEvent);
-			removedPortEvents.remove(id);
-			reorderedAddedPortEvents.remove(id);
-		    }
-		    if (linkEvent != null) {
-			ByteBuffer id = linkEvent.getIDasByteBuffer();
-			addedLinkEvents.put(id, linkEvent);
-			removedLinkEvents.remove(id);
-			reorderedAddedLinkEvents.remove(id);
-		    }
-		    if (deviceEvent != null) {
-			ByteBuffer id = deviceEvent.getIDasByteBuffer();
-			addedDeviceEvents.put(id, deviceEvent);
-			removedDeviceEvents.remove(id);
-			reorderedAddedDeviceEvents.remove(id);
-		    }
-		    break;
-		case ENTRY_REMOVE:
-		    log.debug("Topology event ENTRY_REMOVE: {}", topologyEvent);
-		    if (switchEvent != null) {
-			ByteBuffer id = switchEvent.getIDasByteBuffer();
-			addedSwitchEvents.remove(id);
-			removedSwitchEvents.put(id, switchEvent);
-			// Switch Events are not affected by event reordering
-		    }
-		    if (portEvent != null) {
-			ByteBuffer id = portEvent.getIDasByteBuffer();
-			addedPortEvents.remove(id);
-			removedPortEvents.put(id, portEvent);
-			reorderedAddedPortEvents.remove(id);
-		    }
-		    if (linkEvent != null) {
-			ByteBuffer id = linkEvent.getIDasByteBuffer();
-			addedLinkEvents.remove(id);
-			removedLinkEvents.put(id, linkEvent);
-			reorderedAddedLinkEvents.remove(id);
-		    }
-		    if (deviceEvent != null) {
-			ByteBuffer id = deviceEvent.getIDasByteBuffer();
-			addedDeviceEvents.remove(id);
-			removedDeviceEvents.put(id, deviceEvent);
-			reorderedAddedDeviceEvents.remove(id);
-		    }
-		    break;
-		}
-	    }
+                //
+                // Extract the events
+                //
+                switch (event.eventType()) {
+                    case ENTRY_ADD:
+                        log.debug("Topology event ENTRY_ADD: {}", topologyEvent);
+                        if (switchEvent != null) {
+                            ByteBuffer id = switchEvent.getIDasByteBuffer();
+                            addedSwitchEvents.put(id, switchEvent);
+                            removedSwitchEvents.remove(id);
+                            // Switch Events are not affected by event reordering
+                        }
+                        if (portEvent != null) {
+                            ByteBuffer id = portEvent.getIDasByteBuffer();
+                            addedPortEvents.put(id, portEvent);
+                            removedPortEvents.remove(id);
+                            reorderedAddedPortEvents.remove(id);
+                        }
+                        if (linkEvent != null) {
+                            ByteBuffer id = linkEvent.getIDasByteBuffer();
+                            addedLinkEvents.put(id, linkEvent);
+                            removedLinkEvents.remove(id);
+                            reorderedAddedLinkEvents.remove(id);
+                        }
+                        if (deviceEvent != null) {
+                            ByteBuffer id = deviceEvent.getIDasByteBuffer();
+                            addedDeviceEvents.put(id, deviceEvent);
+                            removedDeviceEvents.remove(id);
+                            reorderedAddedDeviceEvents.remove(id);
+                        }
+                        break;
+                    case ENTRY_REMOVE:
+                        log.debug("Topology event ENTRY_REMOVE: {}", topologyEvent);
+                        if (switchEvent != null) {
+                            ByteBuffer id = switchEvent.getIDasByteBuffer();
+                            addedSwitchEvents.remove(id);
+                            removedSwitchEvents.put(id, switchEvent);
+                            // Switch Events are not affected by event reordering
+                        }
+                        if (portEvent != null) {
+                            ByteBuffer id = portEvent.getIDasByteBuffer();
+                            addedPortEvents.remove(id);
+                            removedPortEvents.put(id, portEvent);
+                            reorderedAddedPortEvents.remove(id);
+                        }
+                        if (linkEvent != null) {
+                            ByteBuffer id = linkEvent.getIDasByteBuffer();
+                            addedLinkEvents.remove(id);
+                            removedLinkEvents.put(id, linkEvent);
+                            reorderedAddedLinkEvents.remove(id);
+                        }
+                        if (deviceEvent != null) {
+                            ByteBuffer id = deviceEvent.getIDasByteBuffer();
+                            addedDeviceEvents.remove(id);
+                            removedDeviceEvents.put(id, deviceEvent);
+                            reorderedAddedDeviceEvents.remove(id);
+                        }
+                        break;
+                }
+            }
 
-	    //
-	    // Lock the Network Graph while it is modified
-	    //
-	    networkGraph.acquireWriteLock();
+            //
+            // Lock the Network Graph while it is modified
+            //
+            networkGraph.acquireWriteLock();
 
-	    try {
-    	    	//
-		// Apply the classified events.
-		//
-		// Apply the "add" events in the proper order:
-		//   switch, port, link, device
-		//
-    	    	for (SwitchEvent switchEvent : addedSwitchEvents.values())
-    	    	    addSwitch(switchEvent);
-    	    	for (PortEvent portEvent : addedPortEvents.values())
-    	    	    addPort(portEvent);
-    	    	for (LinkEvent linkEvent : addedLinkEvents.values())
-    	    	    addLink(linkEvent);
-    	    	for (DeviceEvent deviceEvent : addedDeviceEvents.values())
-    	    	    addDevice(deviceEvent);
-    	    	//
-    	    	// Apply the "remove" events in the reverse order:
-    	    	//   device, link, port, switch
-    	    	//
-    	    	for (DeviceEvent deviceEvent : removedDeviceEvents.values())
-    	    	    removeDevice(deviceEvent);
-    	    	for (LinkEvent linkEvent : removedLinkEvents.values())
-    	    	    removeLink(linkEvent);
-    	    	for (PortEvent portEvent : removedPortEvents.values())
-    	    	    removePort(portEvent);
-    	    	for (SwitchEvent switchEvent : removedSwitchEvents.values())
-    	    	    removeSwitch(switchEvent);
+            try {
+                //
+                // Apply the classified events.
+                //
+                // Apply the "add" events in the proper order:
+                //   switch, port, link, device
+                //
+                for (SwitchEvent switchEvent : addedSwitchEvents.values())
+                    addSwitch(switchEvent);
+                for (PortEvent portEvent : addedPortEvents.values())
+                    addPort(portEvent);
+                for (LinkEvent linkEvent : addedLinkEvents.values())
+                    addLink(linkEvent);
+                for (DeviceEvent deviceEvent : addedDeviceEvents.values())
+                    addDevice(deviceEvent);
+                //
+                // Apply the "remove" events in the reverse order:
+                //   device, link, port, switch
+                //
+                for (DeviceEvent deviceEvent : removedDeviceEvents.values())
+                    removeDevice(deviceEvent);
+                for (LinkEvent linkEvent : removedLinkEvents.values())
+                    removeLink(linkEvent);
+                for (PortEvent portEvent : removedPortEvents.values())
+                    removePort(portEvent);
+                for (SwitchEvent switchEvent : removedSwitchEvents.values())
+                    removeSwitch(switchEvent);
 
-    	    	//
-    	    	// Apply reordered events
-    	    	//
-    	    	applyReorderedEvents(! addedSwitchEvents.isEmpty(),
-    	    				! addedPortEvents.isEmpty());
+                //
+                // Apply reordered events
+                //
+                applyReorderedEvents(!addedSwitchEvents.isEmpty(),
+                        !addedPortEvents.isEmpty());
 
-	    }
-    	    finally {
-    		//
-    		// Network Graph modifications completed: Release the lock
-    		//
-    		networkGraph.releaseWriteLock();
-	    }
+            } finally {
+                //
+                // Network Graph modifications completed: Release the lock
+                //
+                networkGraph.releaseWriteLock();
+            }
 
-	    //
-	    // Dispatch the Topology Notification Events to the applications
-	    //
-	    dispatchNetworkGraphEvents();
-	}
+            //
+            // Dispatch the Topology Notification Events to the applications
+            //
+            dispatchNetworkGraphEvents();
+        }
 
-	/**
-	 * Receive a notification that an entry is added.
-	 *
-	 * @param value the value for the entry.
-	 */
-	@Override
-	public void entryAdded(TopologyEvent value) {
-	    EventEntry<TopologyEvent> eventEntry =
-		new EventEntry<TopologyEvent>(EventEntry.Type.ENTRY_ADD,
-					      value);
-	    topologyEvents.add(eventEntry);
-	}
+        /**
+         * Receive a notification that an entry is added.
+         *
+         * @param value the value for the entry.
+         */
+        @Override
+        public void entryAdded(TopologyEvent value) {
+            EventEntry<TopologyEvent> eventEntry =
+                    new EventEntry<TopologyEvent>(EventEntry.Type.ENTRY_ADD,
+                            value);
+            topologyEvents.add(eventEntry);
+        }
 
-	/**
-	 * Receive a notification that an entry is removed.
-	 *
-	 * @param value the value for the entry.
-	 */
-	@Override
-	public void entryRemoved(TopologyEvent value) {
-	    EventEntry<TopologyEvent> eventEntry =
-		new EventEntry<TopologyEvent>(EventEntry.Type.ENTRY_REMOVE,
-					      value);
-	    topologyEvents.add(eventEntry);
-	}
+        /**
+         * Receive a notification that an entry is removed.
+         *
+         * @param value the value for the entry.
+         */
+        @Override
+        public void entryRemoved(TopologyEvent value) {
+            EventEntry<TopologyEvent> eventEntry =
+                    new EventEntry<TopologyEvent>(EventEntry.Type.ENTRY_REMOVE,
+                            value);
+            topologyEvents.add(eventEntry);
+        }
 
-	/**
-	 * Receive a notification that an entry is updated.
-	 *
-	 * @param value the value for the entry.
-	 */
-	@Override
-	public void entryUpdated(TopologyEvent value) {
-	    // NOTE: The ADD and UPDATE events are processed in same way
-	    entryAdded(value);
-	}
+        /**
+         * Receive a notification that an entry is updated.
+         *
+         * @param value the value for the entry.
+         */
+        @Override
+        public void entryUpdated(TopologyEvent value) {
+            // NOTE: The ADD and UPDATE events are processed in same way
+            entryAdded(value);
+        }
     }
 
     /**
@@ -364,175 +362,175 @@
      * @param datagridService the datagrid service to use.
      */
     void startup(IDatagridService datagridService) {
-	eventChannel = datagridService.addListener(EVENT_CHANNEL_NAME,
-						   eventHandler,
-						   byte[].class,
-						   TopologyEvent.class);
-	eventHandler.start();
+        eventChannel = datagridService.addListener(EVENT_CHANNEL_NAME,
+                eventHandler,
+                byte[].class,
+                TopologyEvent.class);
+        eventHandler.start();
     }
 
     /**
      * Dispatch Network Graph Events to the listeners.
      */
     private void dispatchNetworkGraphEvents() {
-	if (apiAddedSwitchEvents.isEmpty() &&
-	    apiRemovedSwitchEvents.isEmpty() &&
-	    apiAddedPortEvents.isEmpty() &&
-	    apiRemovedPortEvents.isEmpty() &&
-	    apiAddedLinkEvents.isEmpty() &&
-	    apiRemovedLinkEvents.isEmpty() &&
-	    apiAddedDeviceEvents.isEmpty() &&
-	    apiRemovedDeviceEvents.isEmpty()) {
-	    return;		// No events to dispatch
-	}
+        if (apiAddedSwitchEvents.isEmpty() &&
+                apiRemovedSwitchEvents.isEmpty() &&
+                apiAddedPortEvents.isEmpty() &&
+                apiRemovedPortEvents.isEmpty() &&
+                apiAddedLinkEvents.isEmpty() &&
+                apiRemovedLinkEvents.isEmpty() &&
+                apiAddedDeviceEvents.isEmpty() &&
+                apiRemovedDeviceEvents.isEmpty()) {
+            return;        // No events to dispatch
+        }
 
-	if (log.isDebugEnabled()) {
-	    //
-	    // Debug statements
-	    // TODO: Those statements should be removed in the future
-	    //
-	    for (SwitchEvent switchEvent : apiAddedSwitchEvents)
-		log.debug("Dispatch Network Graph Event: ADDED {}", switchEvent);
-	    for (SwitchEvent switchEvent : apiRemovedSwitchEvents)
-		log.debug("Dispatch Network Graph Event: REMOVED {}", switchEvent);
-	    for (PortEvent portEvent : apiAddedPortEvents)
-		log.debug("Dispatch Network Graph Event: ADDED {}", portEvent);
-	    for (PortEvent portEvent : apiRemovedPortEvents)
-		log.debug("Dispatch Network Graph Event: REMOVED {}", portEvent);
-	    for (LinkEvent linkEvent : apiAddedLinkEvents)
-		log.debug("Dispatch Network Graph Event: ADDED {}", linkEvent);
-	    for (LinkEvent linkEvent : apiRemovedLinkEvents)
-		log.debug("Dispatch Network Graph Event: REMOVED {}", linkEvent);
-	    for (DeviceEvent deviceEvent : apiAddedDeviceEvents)
-		log.debug("Dispatch Network Graph Event: ADDED {}", deviceEvent);
-	    for (DeviceEvent deviceEvent : apiRemovedDeviceEvents)
-		log.debug("Dispatch Network Graph Event: REMOVED {}", deviceEvent);
-	}
+        if (log.isDebugEnabled()) {
+            //
+            // Debug statements
+            // TODO: Those statements should be removed in the future
+            //
+            for (SwitchEvent switchEvent : apiAddedSwitchEvents)
+                log.debug("Dispatch Network Graph Event: ADDED {}", switchEvent);
+            for (SwitchEvent switchEvent : apiRemovedSwitchEvents)
+                log.debug("Dispatch Network Graph Event: REMOVED {}", switchEvent);
+            for (PortEvent portEvent : apiAddedPortEvents)
+                log.debug("Dispatch Network Graph Event: ADDED {}", portEvent);
+            for (PortEvent portEvent : apiRemovedPortEvents)
+                log.debug("Dispatch Network Graph Event: REMOVED {}", portEvent);
+            for (LinkEvent linkEvent : apiAddedLinkEvents)
+                log.debug("Dispatch Network Graph Event: ADDED {}", linkEvent);
+            for (LinkEvent linkEvent : apiRemovedLinkEvents)
+                log.debug("Dispatch Network Graph Event: REMOVED {}", linkEvent);
+            for (DeviceEvent deviceEvent : apiAddedDeviceEvents)
+                log.debug("Dispatch Network Graph Event: ADDED {}", deviceEvent);
+            for (DeviceEvent deviceEvent : apiRemovedDeviceEvents)
+                log.debug("Dispatch Network Graph Event: REMOVED {}", deviceEvent);
+        }
 
-	// Deliver the events
-	for (INetworkGraphListener listener : this.networkGraphListeners) {
-	    // TODO: Should copy before handing them over to listener?
-	    listener.networkGraphEvents(apiAddedSwitchEvents,
-					apiRemovedSwitchEvents,
-					apiAddedPortEvents,
-					apiRemovedPortEvents,
-					apiAddedLinkEvents,
-					apiRemovedLinkEvents,
-					apiAddedDeviceEvents,
-					apiRemovedDeviceEvents);
-	}
+        // Deliver the events
+        for (INetworkGraphListener listener : this.networkGraphListeners) {
+            // TODO: Should copy before handing them over to listener?
+            listener.networkGraphEvents(apiAddedSwitchEvents,
+                    apiRemovedSwitchEvents,
+                    apiAddedPortEvents,
+                    apiRemovedPortEvents,
+                    apiAddedLinkEvents,
+                    apiRemovedLinkEvents,
+                    apiAddedDeviceEvents,
+                    apiRemovedDeviceEvents);
+        }
 
-	//
-	// Cleanup
-	//
-	apiAddedSwitchEvents.clear();
-	apiRemovedSwitchEvents.clear();
-	apiAddedPortEvents.clear();
-	apiRemovedPortEvents.clear();
-	apiAddedLinkEvents.clear();
-	apiRemovedLinkEvents.clear();
-	apiAddedDeviceEvents.clear();
-	apiRemovedDeviceEvents.clear();
+        //
+        // Cleanup
+        //
+        apiAddedSwitchEvents.clear();
+        apiRemovedSwitchEvents.clear();
+        apiAddedPortEvents.clear();
+        apiRemovedPortEvents.clear();
+        apiAddedLinkEvents.clear();
+        apiRemovedLinkEvents.clear();
+        apiAddedDeviceEvents.clear();
+        apiRemovedDeviceEvents.clear();
     }
 
     /**
      * Apply reordered events.
      *
      * @param hasAddedSwitchEvents true if there were Added Switch Events.
-     * @param hasAddedPortEvents true if there were Added Port Events.
+     * @param hasAddedPortEvents   true if there were Added Port Events.
      */
     private void applyReorderedEvents(boolean hasAddedSwitchEvents,
-				      boolean hasAddedPortEvents) {
-	if (! (hasAddedSwitchEvents || hasAddedPortEvents))
-	    return;		// Nothing to do
+                                      boolean hasAddedPortEvents) {
+        if (!(hasAddedSwitchEvents || hasAddedPortEvents))
+            return;        // Nothing to do
 
-	//
-	// Try to apply the reordered events.
-	//
-	// NOTE: For simplicity we try to apply all events of a particular
-	// type if any "parent" type event was processed:
-	//  - Apply reordered Port Events if Switches were added
-	//  - Apply reordered Link and Device Events if Switches or Ports
-	//    were added
-	//
+        //
+        // Try to apply the reordered events.
+        //
+        // NOTE: For simplicity we try to apply all events of a particular
+        // type if any "parent" type event was processed:
+        //  - Apply reordered Port Events if Switches were added
+        //  - Apply reordered Link and Device Events if Switches or Ports
+        //    were added
+        //
 
-	//
-	// Apply reordered Port Events if Switches were added
-	//
-	if (hasAddedSwitchEvents) {
-	    Map<ByteBuffer, PortEvent> portEvents = reorderedAddedPortEvents;
-	    reorderedAddedPortEvents = new HashMap<>();
-	    for (PortEvent portEvent : portEvents.values())
-		addPort(portEvent);
-	}
-	//
-	// Apply reordered Link and Device Events if Switches or Ports
-	// were added.
-	//
-	Map<ByteBuffer, LinkEvent> linkEvents = reorderedAddedLinkEvents;
-	reorderedAddedLinkEvents = new HashMap<>();
-	for (LinkEvent linkEvent : linkEvents.values())
-	    addLink(linkEvent);
-	//
-	Map<ByteBuffer, DeviceEvent> deviceEvents = reorderedAddedDeviceEvents;
-	reorderedAddedDeviceEvents = new HashMap<>();
-	for (DeviceEvent deviceEvent : deviceEvents.values())
-	    addDevice(deviceEvent);
+        //
+        // Apply reordered Port Events if Switches were added
+        //
+        if (hasAddedSwitchEvents) {
+            Map<ByteBuffer, PortEvent> portEvents = reorderedAddedPortEvents;
+            reorderedAddedPortEvents = new HashMap<>();
+            for (PortEvent portEvent : portEvents.values())
+                addPort(portEvent);
+        }
+        //
+        // Apply reordered Link and Device Events if Switches or Ports
+        // were added.
+        //
+        Map<ByteBuffer, LinkEvent> linkEvents = reorderedAddedLinkEvents;
+        reorderedAddedLinkEvents = new HashMap<>();
+        for (LinkEvent linkEvent : linkEvents.values())
+            addLink(linkEvent);
+        //
+        Map<ByteBuffer, DeviceEvent> deviceEvents = reorderedAddedDeviceEvents;
+        reorderedAddedDeviceEvents = new HashMap<>();
+        for (DeviceEvent deviceEvent : deviceEvents.values())
+            addDevice(deviceEvent);
     }
 
     /**
      * Switch discovered event.
      *
      * @param switchEvent the switch event.
-     * @param portEvents the corresponding port events for the switch.
+     * @param portEvents  the corresponding port events for the switch.
      */
     @Override
     public void putSwitchDiscoveryEvent(SwitchEvent switchEvent,
-					Collection<PortEvent> portEvents) {
-	if (datastore.addSwitch(switchEvent, portEvents)) {
-	    // Send out notification
-	    TopologyEvent topologyEvent = new TopologyEvent(switchEvent);
-	    eventChannel.addEntry(topologyEvent.getID(), topologyEvent);
-	    
-	    // Send out notification for each port
-	    for (PortEvent portEvent : portEvents) {
-		topologyEvent = new TopologyEvent(portEvent);
-		eventChannel.addEntry(topologyEvent.getID(), topologyEvent);
-	    }
+                                        Collection<PortEvent> portEvents) {
+        if (datastore.addSwitch(switchEvent, portEvents)) {
+            // Send out notification
+            TopologyEvent topologyEvent = new TopologyEvent(switchEvent);
+            eventChannel.addEntry(topologyEvent.getID(), topologyEvent);
 
-	    //
-	    // Keep track of the added ports
-	    //
-	    // Get the old Port Events
-	    Map<ByteBuffer, PortEvent> oldPortEvents =
-		discoveredAddedPortEvents.get(switchEvent.getDpid());
-	    if (oldPortEvents == null)
-		oldPortEvents = new HashMap<>();
+            // Send out notification for each port
+            for (PortEvent portEvent : portEvents) {
+                topologyEvent = new TopologyEvent(portEvent);
+                eventChannel.addEntry(topologyEvent.getID(), topologyEvent);
+            }
 
-	    // Store the new Port Events in the local cache
-	    Map<ByteBuffer, PortEvent> newPortEvents = new HashMap<>();
-	    for (PortEvent portEvent : portEvents) {
-		ByteBuffer id = portEvent.getIDasByteBuffer();
-		newPortEvents.put(id, portEvent);
-	    }
-	    discoveredAddedPortEvents.put(switchEvent.getDpid(),
-					  newPortEvents);
+            //
+            // Keep track of the added ports
+            //
+            // Get the old Port Events
+            Map<ByteBuffer, PortEvent> oldPortEvents =
+                    discoveredAddedPortEvents.get(switchEvent.getDpid());
+            if (oldPortEvents == null)
+                oldPortEvents = new HashMap<>();
 
-	    //
-	    // Extract the removed ports
-	    //
-	    List<PortEvent> removedPortEvents = new LinkedList<>();
-	    for (Map.Entry<ByteBuffer, PortEvent> entry : oldPortEvents.entrySet()) {
-		ByteBuffer key = entry.getKey();
-		PortEvent portEvent = entry.getValue();
-		if (! newPortEvents.containsKey(key))
-		    removedPortEvents.add(portEvent);
-	    }
+            // Store the new Port Events in the local cache
+            Map<ByteBuffer, PortEvent> newPortEvents = new HashMap<>();
+            for (PortEvent portEvent : portEvents) {
+                ByteBuffer id = portEvent.getIDasByteBuffer();
+                newPortEvents.put(id, portEvent);
+            }
+            discoveredAddedPortEvents.put(switchEvent.getDpid(),
+                    newPortEvents);
 
-	    // Cleanup old removed ports
-	    for (PortEvent portEvent : removedPortEvents)
-		removePortDiscoveryEvent(portEvent);
-	}
+            //
+            // Extract the removed ports
+            //
+            List<PortEvent> removedPortEvents = new LinkedList<>();
+            for (Map.Entry<ByteBuffer, PortEvent> entry : oldPortEvents.entrySet()) {
+                ByteBuffer key = entry.getKey();
+                PortEvent portEvent = entry.getValue();
+                if (!newPortEvents.containsKey(key))
+                    removedPortEvents.add(portEvent);
+            }
+
+            // Cleanup old removed ports
+            for (PortEvent portEvent : removedPortEvents)
+                removePortDiscoveryEvent(portEvent);
+        }
     }
 
     /**
@@ -542,47 +540,47 @@
      */
     @Override
     public void removeSwitchDiscoveryEvent(SwitchEvent switchEvent) {
-	// Get the old Port Events
-	Map<ByteBuffer, PortEvent> oldPortEvents =
-	    discoveredAddedPortEvents.get(switchEvent.getDpid());
-	if (oldPortEvents == null)
-	    oldPortEvents = new HashMap<>();
+        // Get the old Port Events
+        Map<ByteBuffer, PortEvent> oldPortEvents =
+                discoveredAddedPortEvents.get(switchEvent.getDpid());
+        if (oldPortEvents == null)
+            oldPortEvents = new HashMap<>();
 
-	if (datastore.deactivateSwitch(switchEvent, oldPortEvents.values())) {
-	    // Send out notification
-	    eventChannel.removeEntry(switchEvent.getID());
+        if (datastore.deactivateSwitch(switchEvent, oldPortEvents.values())) {
+            // Send out notification
+            eventChannel.removeEntry(switchEvent.getID());
 
-	    //
-	    // Send out notification for each port.
-	    //
-	    // NOTE: We don't use removePortDiscoveryEvent() for the cleanup,
-	    // because it will attempt to remove the port from the database,
-	    // and the deactiveSwitch() call above already removed all ports.
-	    //
-	    for (PortEvent portEvent : oldPortEvents.values())
-		eventChannel.removeEntry(portEvent.getID());
-	    discoveredAddedPortEvents.remove(switchEvent.getDpid());
+            //
+            // Send out notification for each port.
+            //
+            // NOTE: We don't use removePortDiscoveryEvent() for the cleanup,
+            // because it will attempt to remove the port from the database,
+            // and the deactiveSwitch() call above already removed all ports.
+            //
+            for (PortEvent portEvent : oldPortEvents.values())
+                eventChannel.removeEntry(portEvent.getID());
+            discoveredAddedPortEvents.remove(switchEvent.getDpid());
 
-	    // Cleanup for each link
-	    Map<ByteBuffer, LinkEvent> oldLinkEvents =
-		discoveredAddedLinkEvents.get(switchEvent.getDpid());
-	    if (oldLinkEvents != null) {
-		for (LinkEvent linkEvent : new ArrayList<>(oldLinkEvents.values())) {
-		    removeLinkDiscoveryEvent(linkEvent);
-		}
-		discoveredAddedLinkEvents.remove(switchEvent.getDpid());
-	    }
+            // Cleanup for each link
+            Map<ByteBuffer, LinkEvent> oldLinkEvents =
+                    discoveredAddedLinkEvents.get(switchEvent.getDpid());
+            if (oldLinkEvents != null) {
+                for (LinkEvent linkEvent : new ArrayList<>(oldLinkEvents.values())) {
+                    removeLinkDiscoveryEvent(linkEvent);
+                }
+                discoveredAddedLinkEvents.remove(switchEvent.getDpid());
+            }
 
-	    // Cleanup for each device
-	    Map<ByteBuffer, DeviceEvent> oldDeviceEvents =
-		discoveredAddedDeviceEvents.get(switchEvent.getDpid());
-	    if (oldDeviceEvents != null) {
-		for (DeviceEvent deviceEvent : new ArrayList<>(oldDeviceEvents.values())) {
-		    removeDeviceDiscoveryEvent(deviceEvent);
-		}
-		discoveredAddedDeviceEvents.remove(switchEvent.getDpid());
-	    }
-	}
+            // Cleanup for each device
+            Map<ByteBuffer, DeviceEvent> oldDeviceEvents =
+                    discoveredAddedDeviceEvents.get(switchEvent.getDpid());
+            if (oldDeviceEvents != null) {
+                for (DeviceEvent deviceEvent : new ArrayList<>(oldDeviceEvents.values())) {
+                    removeDeviceDiscoveryEvent(deviceEvent);
+                }
+                discoveredAddedDeviceEvents.remove(switchEvent.getDpid());
+            }
+        }
     }
 
     /**
@@ -592,22 +590,22 @@
      */
     @Override
     public void putPortDiscoveryEvent(PortEvent portEvent) {
-	if (datastore.addPort(portEvent)) {
-	    // Send out notification
-	    TopologyEvent topologyEvent = new TopologyEvent(portEvent);
-	    eventChannel.addEntry(topologyEvent.getID(), topologyEvent);
+        if (datastore.addPort(portEvent)) {
+            // Send out notification
+            TopologyEvent topologyEvent = new TopologyEvent(portEvent);
+            eventChannel.addEntry(topologyEvent.getID(), topologyEvent);
 
-	    // Store the new Port Event in the local cache
-	    Map<ByteBuffer, PortEvent> oldPortEvents =
-		discoveredAddedPortEvents.get(portEvent.getDpid());
-	    if (oldPortEvents == null) {
-		oldPortEvents = new HashMap<>();
-		discoveredAddedPortEvents.put(portEvent.getDpid(),
-					      oldPortEvents);
-	    }
-	    ByteBuffer id = portEvent.getIDasByteBuffer();
-	    oldPortEvents.put(id, portEvent);
-	}
+            // Store the new Port Event in the local cache
+            Map<ByteBuffer, PortEvent> oldPortEvents =
+                    discoveredAddedPortEvents.get(portEvent.getDpid());
+            if (oldPortEvents == null) {
+                oldPortEvents = new HashMap<>();
+                discoveredAddedPortEvents.put(portEvent.getDpid(),
+                        oldPortEvents);
+            }
+            ByteBuffer id = portEvent.getIDasByteBuffer();
+            oldPortEvents.put(id, portEvent);
+        }
     }
 
     /**
@@ -617,49 +615,49 @@
      */
     @Override
     public void removePortDiscoveryEvent(PortEvent portEvent) {
-	if (datastore.deactivatePort(portEvent)) {
-	    // Send out notification
-	    eventChannel.removeEntry(portEvent.getID());
+        if (datastore.deactivatePort(portEvent)) {
+            // Send out notification
+            eventChannel.removeEntry(portEvent.getID());
 
-	    // Cleanup the Port Event from the local cache
-	    Map<ByteBuffer, PortEvent> oldPortEvents =
-		discoveredAddedPortEvents.get(portEvent.getDpid());
-	    if (oldPortEvents != null) {
-		ByteBuffer id = portEvent.getIDasByteBuffer();
-		oldPortEvents.remove(id);
-	    }
+            // Cleanup the Port Event from the local cache
+            Map<ByteBuffer, PortEvent> oldPortEvents =
+                    discoveredAddedPortEvents.get(portEvent.getDpid());
+            if (oldPortEvents != null) {
+                ByteBuffer id = portEvent.getIDasByteBuffer();
+                oldPortEvents.remove(id);
+            }
 
-	    // Cleanup for the incoming link
-	    Map<ByteBuffer, LinkEvent> oldLinkEvents =
-		discoveredAddedLinkEvents.get(portEvent.getDpid());
-	    if (oldLinkEvents != null) {
-		for (LinkEvent linkEvent : new ArrayList<>(oldLinkEvents.values())) {
-		    if (linkEvent.getDst().equals(portEvent.id)) {
-			removeLinkDiscoveryEvent(linkEvent);
-			// XXX If we change our model to allow multiple Link on
-			// a Port, this loop must be fixed to allow continuing.
-			break;
-		    }
-		}
-	    }
+            // Cleanup for the incoming link
+            Map<ByteBuffer, LinkEvent> oldLinkEvents =
+                    discoveredAddedLinkEvents.get(portEvent.getDpid());
+            if (oldLinkEvents != null) {
+                for (LinkEvent linkEvent : new ArrayList<>(oldLinkEvents.values())) {
+                    if (linkEvent.getDst().equals(portEvent.id)) {
+                        removeLinkDiscoveryEvent(linkEvent);
+                        // XXX If we change our model to allow multiple Link on
+                        // a Port, this loop must be fixed to allow continuing.
+                        break;
+                    }
+                }
+            }
 
-	    // Cleanup for the connected devices
-	    // TODO: The implementation below is probably wrong
-	    List<DeviceEvent> removedDeviceEvents = new LinkedList<>();
-	    Map<ByteBuffer, DeviceEvent> oldDeviceEvents =
-		discoveredAddedDeviceEvents.get(portEvent.getDpid());
-	    if (oldDeviceEvents != null) {
-		for (DeviceEvent deviceEvent : new ArrayList<>(oldDeviceEvents.values())) {
-		    for (SwitchPort swp : deviceEvent.getAttachmentPoints()) {
-			if (swp.equals(portEvent.id)) {
-			    removedDeviceEvents.add(deviceEvent);
-			}
-		    }
-		}
-		for (DeviceEvent deviceEvent : removedDeviceEvents)
-		    removeDeviceDiscoveryEvent(deviceEvent);
-	    }
-	}
+            // Cleanup for the connected devices
+            // TODO: The implementation below is probably wrong
+            List<DeviceEvent> removedDeviceEvents = new LinkedList<>();
+            Map<ByteBuffer, DeviceEvent> oldDeviceEvents =
+                    discoveredAddedDeviceEvents.get(portEvent.getDpid());
+            if (oldDeviceEvents != null) {
+                for (DeviceEvent deviceEvent : new ArrayList<>(oldDeviceEvents.values())) {
+                    for (SwitchPort swp : deviceEvent.getAttachmentPoints()) {
+                        if (swp.equals(portEvent.id)) {
+                            removedDeviceEvents.add(deviceEvent);
+                        }
+                    }
+                }
+                for (DeviceEvent deviceEvent : removedDeviceEvents)
+                    removeDeviceDiscoveryEvent(deviceEvent);
+            }
+        }
     }
 
     /**
@@ -669,22 +667,22 @@
      */
     @Override
     public void putLinkDiscoveryEvent(LinkEvent linkEvent) {
-	if (datastore.addLink(linkEvent)) {
-	    // Send out notification
-	    TopologyEvent topologyEvent = new TopologyEvent(linkEvent);
-	    eventChannel.addEntry(topologyEvent.getID(), topologyEvent);
+        if (datastore.addLink(linkEvent)) {
+            // Send out notification
+            TopologyEvent topologyEvent = new TopologyEvent(linkEvent);
+            eventChannel.addEntry(topologyEvent.getID(), topologyEvent);
 
-	    // Store the new Link Event in the local cache
-	    Map<ByteBuffer, LinkEvent> oldLinkEvents =
-		discoveredAddedLinkEvents.get(linkEvent.getDst().getDpid());
-	    if (oldLinkEvents == null) {
-		oldLinkEvents = new HashMap<>();
-		discoveredAddedLinkEvents.put(linkEvent.getDst().getDpid(),
-					      oldLinkEvents);
-	    }
-	    ByteBuffer id = linkEvent.getIDasByteBuffer();
-	    oldLinkEvents.put(id, linkEvent);
-	}
+            // Store the new Link Event in the local cache
+            Map<ByteBuffer, LinkEvent> oldLinkEvents =
+                    discoveredAddedLinkEvents.get(linkEvent.getDst().getDpid());
+            if (oldLinkEvents == null) {
+                oldLinkEvents = new HashMap<>();
+                discoveredAddedLinkEvents.put(linkEvent.getDst().getDpid(),
+                        oldLinkEvents);
+            }
+            ByteBuffer id = linkEvent.getIDasByteBuffer();
+            oldLinkEvents.put(id, linkEvent);
+        }
     }
 
     /**
@@ -694,18 +692,18 @@
      */
     @Override
     public void removeLinkDiscoveryEvent(LinkEvent linkEvent) {
-	if (datastore.removeLink(linkEvent)) {
-	    // Send out notification
-	    eventChannel.removeEntry(linkEvent.getID());
+        if (datastore.removeLink(linkEvent)) {
+            // Send out notification
+            eventChannel.removeEntry(linkEvent.getID());
 
-	    // Cleanup the Link Event from the local cache
-	    Map<ByteBuffer, LinkEvent> oldLinkEvents =
-		discoveredAddedLinkEvents.get(linkEvent.getDst().getDpid());
-	    if (oldLinkEvents != null) {
-		ByteBuffer id = linkEvent.getIDasByteBuffer();
-		oldLinkEvents.remove(id);
-	    }
-	}
+            // Cleanup the Link Event from the local cache
+            Map<ByteBuffer, LinkEvent> oldLinkEvents =
+                    discoveredAddedLinkEvents.get(linkEvent.getDst().getDpid());
+            if (oldLinkEvents != null) {
+                ByteBuffer id = linkEvent.getIDasByteBuffer();
+                oldLinkEvents.remove(id);
+            }
+        }
     }
 
     /**
@@ -715,26 +713,26 @@
      */
     @Override
     public void putDeviceDiscoveryEvent(DeviceEvent deviceEvent) {
-	if (datastore.addDevice(deviceEvent)) {
-	    // Send out notification
-	    TopologyEvent topologyEvent = new TopologyEvent(deviceEvent);
-	    eventChannel.addEntry(topologyEvent.getID(), topologyEvent);
-	    log.debug("Put the device info into the cache of the graph. mac {}", deviceEvent.getMac());
-	    
-	    // Store the new Device Event in the local cache
-	    // TODO: The implementation below is probably wrong
-	    for (SwitchPort swp : deviceEvent.getAttachmentPoints()) {
-		Map<ByteBuffer, DeviceEvent> oldDeviceEvents =
-		    discoveredAddedDeviceEvents.get(swp.getDpid());
-		if (oldDeviceEvents == null) {
-		    oldDeviceEvents = new HashMap<>();
-		    discoveredAddedDeviceEvents.put(swp.getDpid(),
-						    oldDeviceEvents);
-		}
-		ByteBuffer id = deviceEvent.getIDasByteBuffer();
-		oldDeviceEvents.put(id, deviceEvent);
-	    }
-	}
+        if (datastore.addDevice(deviceEvent)) {
+            // Send out notification
+            TopologyEvent topologyEvent = new TopologyEvent(deviceEvent);
+            eventChannel.addEntry(topologyEvent.getID(), topologyEvent);
+            log.debug("Put the device info into the cache of the graph. mac {}", deviceEvent.getMac());
+
+            // Store the new Device Event in the local cache
+            // TODO: The implementation below is probably wrong
+            for (SwitchPort swp : deviceEvent.getAttachmentPoints()) {
+                Map<ByteBuffer, DeviceEvent> oldDeviceEvents =
+                        discoveredAddedDeviceEvents.get(swp.getDpid());
+                if (oldDeviceEvents == null) {
+                    oldDeviceEvents = new HashMap<>();
+                    discoveredAddedDeviceEvents.put(swp.getDpid(),
+                            oldDeviceEvents);
+                }
+                ByteBuffer id = deviceEvent.getIDasByteBuffer();
+                oldDeviceEvents.put(id, deviceEvent);
+            }
+        }
     }
 
     /**
@@ -744,22 +742,22 @@
      */
     @Override
     public void removeDeviceDiscoveryEvent(DeviceEvent deviceEvent) {
-	if (datastore.removeDevice(deviceEvent)) {
-	    // Send out notification
-	    eventChannel.removeEntry(deviceEvent.getID());
-	    log.debug("Remove the device info into the cache of the graph. mac {}", deviceEvent.getMac());
+        if (datastore.removeDevice(deviceEvent)) {
+            // Send out notification
+            eventChannel.removeEntry(deviceEvent.getID());
+            log.debug("Remove the device info into the cache of the graph. mac {}", deviceEvent.getMac());
 
-	    // Cleanup the Device Event from the local cache
-	    // TODO: The implementation below is probably wrong
-	    ByteBuffer id = ByteBuffer.wrap(deviceEvent.getID());
-	    for (SwitchPort swp : deviceEvent.getAttachmentPoints()) {
-		Map<ByteBuffer, DeviceEvent> oldDeviceEvents =
-		    discoveredAddedDeviceEvents.get(swp.getDpid());
-		if (oldDeviceEvents != null) {
-		    oldDeviceEvents.remove(id);
-		}
-	    }
-	}
+            // Cleanup the Device Event from the local cache
+            // TODO: The implementation below is probably wrong
+            ByteBuffer id = ByteBuffer.wrap(deviceEvent.getID());
+            for (SwitchPort swp : deviceEvent.getAttachmentPoints()) {
+                Map<ByteBuffer, DeviceEvent> oldDeviceEvents =
+                        discoveredAddedDeviceEvents.get(swp.getDpid());
+                if (oldDeviceEvents != null) {
+                    oldDeviceEvents.remove(id);
+                }
+            }
+        }
     }
 
     /**
@@ -768,15 +766,15 @@
      * @param switchEvent the Switch Event with the switch to add.
      */
     private void addSwitch(SwitchEvent switchEvent) {
-	Switch sw = networkGraph.getSwitch(switchEvent.getDpid());
-	if (sw == null) {
-	    sw = new SwitchImpl(networkGraph, switchEvent.getDpid());
-	    networkGraph.putSwitch(sw);
-	} else {
-	    // TODO: Update the switch attributes
-	    // TODO: Nothing to do for now
-	}
-	apiAddedSwitchEvents.add(switchEvent);
+        Switch sw = networkGraph.getSwitch(switchEvent.getDpid());
+        if (sw == null) {
+            sw = new SwitchImpl(networkGraph, switchEvent.getDpid());
+            networkGraph.putSwitch(sw);
+        } else {
+            // TODO: Update the switch attributes
+            // TODO: Nothing to do for now
+        }
+        apiAddedSwitchEvents.add(switchEvent);
     }
 
     /**
@@ -785,28 +783,28 @@
      * @param switchEvent the Switch Event with the switch to remove.
      */
     private void removeSwitch(SwitchEvent switchEvent) {
-	Switch sw = networkGraph.getSwitch(switchEvent.getDpid());
-	if (sw == null) {
-	    log.warn("Switch {} already removed, ignoring", switchEvent);
-	    return;
-	}
+        Switch sw = networkGraph.getSwitch(switchEvent.getDpid());
+        if (sw == null) {
+            log.warn("Switch {} already removed, ignoring", switchEvent);
+            return;
+        }
 
-	//
-	// Remove all Ports on the Switch
-	//
-	ArrayList<PortEvent> portsToRemove = new ArrayList<>();
-	for (Port port : sw.getPorts()) {
-	    log.warn("Port {} on Switch {} should be removed prior to removing Switch. Removing Port now.",
-		     port, switchEvent);
-	    PortEvent portEvent = new PortEvent(port.getDpid(),
-						port.getNumber());
-	    portsToRemove.add(portEvent);
-	}
-	for (PortEvent portEvent : portsToRemove)
-	    removePort(portEvent);
+        //
+        // Remove all Ports on the Switch
+        //
+        ArrayList<PortEvent> portsToRemove = new ArrayList<>();
+        for (Port port : sw.getPorts()) {
+            log.warn("Port {} on Switch {} should be removed prior to removing Switch. Removing Port now.",
+                    port, switchEvent);
+            PortEvent portEvent = new PortEvent(port.getDpid(),
+                    port.getNumber());
+            portsToRemove.add(portEvent);
+        }
+        for (PortEvent portEvent : portsToRemove)
+            removePort(portEvent);
 
-	networkGraph.removeSwitch(switchEvent.getDpid());
-	apiRemovedSwitchEvents.add(switchEvent);
+        networkGraph.removeSwitch(switchEvent.getDpid());
+        apiRemovedSwitchEvents.add(switchEvent);
     }
 
     /**
@@ -815,23 +813,23 @@
      * @param portEvent the Port Event with the port to add.
      */
     private void addPort(PortEvent portEvent) {
-	Switch sw = networkGraph.getSwitch(portEvent.getDpid());
-	if (sw == null) {
-	    // Reordered event: delay the event in local cache
-	    ByteBuffer id = portEvent.getIDasByteBuffer();
-	    reorderedAddedPortEvents.put(id, portEvent);
-	    return;
-	}
-	SwitchImpl switchImpl = getSwitchImpl(sw);
+        Switch sw = networkGraph.getSwitch(portEvent.getDpid());
+        if (sw == null) {
+            // Reordered event: delay the event in local cache
+            ByteBuffer id = portEvent.getIDasByteBuffer();
+            reorderedAddedPortEvents.put(id, portEvent);
+            return;
+        }
+        SwitchImpl switchImpl = getSwitchImpl(sw);
 
-	Port port = sw.getPort(portEvent.getNumber());
-	if (port == null) {
-	    port = new PortImpl(networkGraph, sw, portEvent.getNumber());
-	    switchImpl.addPort(port);
-	} else {
-	    // TODO: Update the port attributes
-	}
-	apiAddedPortEvents.add(portEvent);
+        Port port = sw.getPort(portEvent.getNumber());
+        if (port == null) {
+            port = new PortImpl(networkGraph, sw, portEvent.getNumber());
+            switchImpl.addPort(port);
+        } else {
+            // TODO: Update the port attributes
+        }
+        apiAddedPortEvents.add(portEvent);
     }
 
     /**
@@ -840,59 +838,59 @@
      * @param portEvent the Port Event with the port to remove.
      */
     private void removePort(PortEvent portEvent) {
-	Switch sw = networkGraph.getSwitch(portEvent.getDpid());
-	if (sw == null) {
-	    log.warn("Parent Switch for Port {} already removed, ignoring",
-		     portEvent);
-	    return;
-	}
+        Switch sw = networkGraph.getSwitch(portEvent.getDpid());
+        if (sw == null) {
+            log.warn("Parent Switch for Port {} already removed, ignoring",
+                    portEvent);
+            return;
+        }
 
-	Port port = sw.getPort(portEvent.getNumber());
-	if (port == null) {
-	    log.warn("Port {} already removed, ignoring", portEvent);
-	    return;
-	}
+        Port port = sw.getPort(portEvent.getNumber());
+        if (port == null) {
+            log.warn("Port {} already removed, ignoring", portEvent);
+            return;
+        }
 
-	//
-	// Remove all Devices attached to the Port
-	//
-	ArrayList<DeviceEvent> devicesToRemove = new ArrayList<>();
-	for (Device device : port.getDevices()) {
-	    log.debug("Removing Device {} on Port {}", device, portEvent);
-	    DeviceEvent deviceEvent = new DeviceEvent(device.getMacAddress());
-	    SwitchPort switchPort = new SwitchPort(port.getSwitch().getDpid(),
-						   port.getNumber());
-	    deviceEvent.addAttachmentPoint(switchPort);
-	    devicesToRemove.add(deviceEvent);
-	}
-	for (DeviceEvent deviceEvent : devicesToRemove)
-	    removeDevice(deviceEvent);
+        //
+        // Remove all Devices attached to the Port
+        //
+        ArrayList<DeviceEvent> devicesToRemove = new ArrayList<>();
+        for (Device device : port.getDevices()) {
+            log.debug("Removing Device {} on Port {}", device, portEvent);
+            DeviceEvent deviceEvent = new DeviceEvent(device.getMacAddress());
+            SwitchPort switchPort = new SwitchPort(port.getSwitch().getDpid(),
+                    port.getNumber());
+            deviceEvent.addAttachmentPoint(switchPort);
+            devicesToRemove.add(deviceEvent);
+        }
+        for (DeviceEvent deviceEvent : devicesToRemove)
+            removeDevice(deviceEvent);
 
-	//
-	// Remove all Links connected to the Port
-	//
-	Set<Link> links = new HashSet<>();
-	links.add(port.getOutgoingLink());
-	links.add(port.getIncomingLink());
-	ArrayList<LinkEvent> linksToRemove = new ArrayList<>();
-	for (Link link : links) {
-	    if (link == null)
-		continue;
-	    log.debug("Removing Link {} on Port {}", link, portEvent);
-	    LinkEvent linkEvent = new LinkEvent(link.getSrcSwitch().getDpid(),
-						link.getSrcPort().getNumber(),
-						link.getDstSwitch().getDpid(),
-						link.getDstPort().getNumber());
-	    linksToRemove.add(linkEvent);
-	}
-	for (LinkEvent linkEvent : linksToRemove)
-	    removeLink(linkEvent);
+        //
+        // Remove all Links connected to the Port
+        //
+        Set<Link> links = new HashSet<>();
+        links.add(port.getOutgoingLink());
+        links.add(port.getIncomingLink());
+        ArrayList<LinkEvent> linksToRemove = new ArrayList<>();
+        for (Link link : links) {
+            if (link == null)
+                continue;
+            log.debug("Removing Link {} on Port {}", link, portEvent);
+            LinkEvent linkEvent = new LinkEvent(link.getSrcSwitch().getDpid(),
+                    link.getSrcPort().getNumber(),
+                    link.getDstSwitch().getDpid(),
+                    link.getDstPort().getNumber());
+            linksToRemove.add(linkEvent);
+        }
+        for (LinkEvent linkEvent : linksToRemove)
+            removeLink(linkEvent);
 
-	// Remove the Port from the Switch
-	SwitchImpl switchImpl = getSwitchImpl(sw);
-	switchImpl.removePort(port);
+        // Remove the Port from the Switch
+        SwitchImpl switchImpl = getSwitchImpl(sw);
+        switchImpl.removePort(port);
 
-	apiRemovedPortEvents.add(portEvent);
+        apiRemovedPortEvents.add(portEvent);
     }
 
     /**
@@ -901,52 +899,52 @@
      * @param linkEvent the Link Event with the link to add.
      */
     private void addLink(LinkEvent linkEvent) {
-	Port srcPort = networkGraph.getPort(linkEvent.getSrc().dpid,
-					    linkEvent.getSrc().number);
-	Port dstPort = networkGraph.getPort(linkEvent.getDst().dpid,
-					    linkEvent.getDst().number);
-	if ((srcPort == null) || (dstPort == null)) {
-	    // Reordered event: delay the event in local cache
-	    ByteBuffer id = linkEvent.getIDasByteBuffer();
-	    reorderedAddedLinkEvents.put(id, linkEvent);
-	    return;
-	}
+        Port srcPort = networkGraph.getPort(linkEvent.getSrc().dpid,
+                linkEvent.getSrc().number);
+        Port dstPort = networkGraph.getPort(linkEvent.getDst().dpid,
+                linkEvent.getDst().number);
+        if ((srcPort == null) || (dstPort == null)) {
+            // Reordered event: delay the event in local cache
+            ByteBuffer id = linkEvent.getIDasByteBuffer();
+            reorderedAddedLinkEvents.put(id, linkEvent);
+            return;
+        }
 
-	// Get the Link instance from the Destination Port Incoming Link
-	Link link = dstPort.getIncomingLink();
-	assert(link == srcPort.getOutgoingLink());
-	if (link == null) {
-	    link = new LinkImpl(networkGraph, srcPort, dstPort);
-	    PortImpl srcPortImpl = getPortImpl(srcPort);
-	    PortImpl dstPortImpl = getPortImpl(dstPort);
-	    srcPortImpl.setOutgoingLink(link);
-	    dstPortImpl.setIncomingLink(link);
+        // Get the Link instance from the Destination Port Incoming Link
+        Link link = dstPort.getIncomingLink();
+        assert (link == srcPort.getOutgoingLink());
+        if (link == null) {
+            link = new LinkImpl(networkGraph, srcPort, dstPort);
+            PortImpl srcPortImpl = getPortImpl(srcPort);
+            PortImpl dstPortImpl = getPortImpl(dstPort);
+            srcPortImpl.setOutgoingLink(link);
+            dstPortImpl.setIncomingLink(link);
 
-	    // Remove all Devices attached to the Ports
-	    ArrayList<DeviceEvent> devicesToRemove = new ArrayList<>();
-	    ArrayList<Port> ports = new ArrayList<>();
-	    ports.add(srcPort);
-	    ports.add(dstPort);
-	    for (Port port : ports) {
-		for (Device device : port.getDevices()) {
-		    log.error("Device {} on Port {} should have been removed prior to adding Link {}",
-			      device, port, linkEvent);
-		    DeviceEvent deviceEvent =
-			new DeviceEvent(device.getMacAddress());
-		    SwitchPort switchPort =
-			new SwitchPort(port.getSwitch().getDpid(),
-				       port.getNumber());
-		    deviceEvent.addAttachmentPoint(switchPort);
-		    devicesToRemove.add(deviceEvent);
-		}
-	    }
-	    for (DeviceEvent deviceEvent : devicesToRemove)
-		removeDevice(deviceEvent);
-	} else {
-	    // TODO: Update the link attributes
-	}
+            // Remove all Devices attached to the Ports
+            ArrayList<DeviceEvent> devicesToRemove = new ArrayList<>();
+            ArrayList<Port> ports = new ArrayList<>();
+            ports.add(srcPort);
+            ports.add(dstPort);
+            for (Port port : ports) {
+                for (Device device : port.getDevices()) {
+                    log.error("Device {} on Port {} should have been removed prior to adding Link {}",
+                            device, port, linkEvent);
+                    DeviceEvent deviceEvent =
+                            new DeviceEvent(device.getMacAddress());
+                    SwitchPort switchPort =
+                            new SwitchPort(port.getSwitch().getDpid(),
+                                    port.getNumber());
+                    deviceEvent.addAttachmentPoint(switchPort);
+                    devicesToRemove.add(deviceEvent);
+                }
+            }
+            for (DeviceEvent deviceEvent : devicesToRemove)
+                removeDevice(deviceEvent);
+        } else {
+            // TODO: Update the link attributes
+        }
 
-	apiAddedLinkEvents.add(linkEvent);
+        apiAddedLinkEvents.add(linkEvent);
     }
 
     /**
@@ -955,43 +953,43 @@
      * @param linkEvent the Link Event with the link to remove.
      */
     private void removeLink(LinkEvent linkEvent) {
-	Port srcPort = networkGraph.getPort(linkEvent.getSrc().dpid,
-					    linkEvent.getSrc().number);
-	if (srcPort == null) {
-	    log.warn("Src Port for Link {} already removed, ignoring",
-		     linkEvent);
-	    return;
-	}
+        Port srcPort = networkGraph.getPort(linkEvent.getSrc().dpid,
+                linkEvent.getSrc().number);
+        if (srcPort == null) {
+            log.warn("Src Port for Link {} already removed, ignoring",
+                    linkEvent);
+            return;
+        }
 
-	Port dstPort = networkGraph.getPort(linkEvent.getDst().dpid,
-					    linkEvent.getDst().number);
-	if (dstPort == null) {
-	    log.warn("Dst Port for Link {} already removed, ignoring",
-		     linkEvent);
-	    return;
-	}
+        Port dstPort = networkGraph.getPort(linkEvent.getDst().dpid,
+                linkEvent.getDst().number);
+        if (dstPort == null) {
+            log.warn("Dst Port for Link {} already removed, ignoring",
+                    linkEvent);
+            return;
+        }
 
-	//
-	// Remove the Link instance from the Destination Port Incoming Link
-	// and the Source Port Outgoing Link.
-	//
-	Link link = dstPort.getIncomingLink();
-	if (link == null) {
-	    log.warn("Link {} already removed on destination Port", linkEvent);
-	}
-	link = srcPort.getOutgoingLink();
-	if (link == null) {
-	    log.warn("Link {} already removed on src Port", linkEvent);
-	}
-	getPortImpl(dstPort).setIncomingLink(null);
-	getPortImpl(srcPort).setOutgoingLink(null);
+        //
+        // Remove the Link instance from the Destination Port Incoming Link
+        // and the Source Port Outgoing Link.
+        //
+        Link link = dstPort.getIncomingLink();
+        if (link == null) {
+            log.warn("Link {} already removed on destination Port", linkEvent);
+        }
+        link = srcPort.getOutgoingLink();
+        if (link == null) {
+            log.warn("Link {} already removed on src Port", linkEvent);
+        }
+        getPortImpl(dstPort).setIncomingLink(null);
+        getPortImpl(srcPort).setOutgoingLink(null);
 
-	apiRemovedLinkEvents.add(linkEvent);
+        apiRemovedLinkEvents.add(linkEvent);
     }
 
     /**
      * Add a device to the Network Graph.
-     *
+     * <p/>
      * TODO: Device-related work is incomplete.
      * TODO: Eventually, we might need to consider reordering
      * or addLink() and addDevice() events on the same port.
@@ -999,86 +997,86 @@
      * @param deviceEvent the Device Event with the device to add.
      */
     private void addDevice(DeviceEvent deviceEvent) {
-	Device device = networkGraph.getDeviceByMac(deviceEvent.getMac());
-	
-	if (device == null) {
-		log.debug("Existing device was not found in networkGraph. New device. mac {}", deviceEvent.getMac());
-	    device = new DeviceImpl(networkGraph, deviceEvent.getMac());
-	}
-	
-	DeviceImpl deviceImpl = getDeviceImpl(device);
+        Device device = networkGraph.getDeviceByMac(deviceEvent.getMac());
 
-	// Update the IP addresses
-	for (InetAddress ipAddr : deviceEvent.getIpAddresses())
-	    deviceImpl.addIpAddress(ipAddr);
+        if (device == null) {
+            log.debug("Existing device was not found in networkGraph. New device. mac {}", deviceEvent.getMac());
+            device = new DeviceImpl(networkGraph, deviceEvent.getMac());
+        }
 
-	// Process each attachment point
-	boolean attachmentFound = false;
-	for (SwitchPort swp : deviceEvent.getAttachmentPoints()) {
-	    // Attached Ports must exist
-	    Port port = networkGraph.getPort(swp.dpid, swp.number);
-	    if (port == null) {
-		// Reordered event: delay the event in local cache
-		ByteBuffer id = deviceEvent.getIDasByteBuffer();
-		reorderedAddedDeviceEvents.put(id, deviceEvent);
-		continue;
-	    }
-	    // Attached Ports must not have Link
-	    if (port.getOutgoingLink() != null ||
-		port.getIncomingLink() != null) {
-		log.warn("Link (Out:{},In:{}) exist on the attachment point, skipping mutation.",
-			 port.getOutgoingLink(),
-			 port.getIncomingLink());
-		continue;
-	    }
+        DeviceImpl deviceImpl = getDeviceImpl(device);
 
-	    // Add Device <-> Port attachment
-	    PortImpl portImpl = getPortImpl(port);
-	    portImpl.addDevice(device);
-	    deviceImpl.addAttachmentPoint(port);
-	    attachmentFound = true;
-	}
+        // Update the IP addresses
+        for (InetAddress ipAddr : deviceEvent.getIpAddresses())
+            deviceImpl.addIpAddress(ipAddr);
 
-	// Update the device in the Network Graph
-	if (attachmentFound) {
-    	log.debug("Storing the info into networkGraph. mac {}", deviceEvent.getMac());
-	    networkGraph.putDevice(device);
-	    apiAddedDeviceEvents.add(deviceEvent);
-	}
+        // Process each attachment point
+        boolean attachmentFound = false;
+        for (SwitchPort swp : deviceEvent.getAttachmentPoints()) {
+            // Attached Ports must exist
+            Port port = networkGraph.getPort(swp.dpid, swp.number);
+            if (port == null) {
+                // Reordered event: delay the event in local cache
+                ByteBuffer id = deviceEvent.getIDasByteBuffer();
+                reorderedAddedDeviceEvents.put(id, deviceEvent);
+                continue;
+            }
+            // Attached Ports must not have Link
+            if (port.getOutgoingLink() != null ||
+                    port.getIncomingLink() != null) {
+                log.warn("Link (Out:{},In:{}) exist on the attachment point, skipping mutation.",
+                        port.getOutgoingLink(),
+                        port.getIncomingLink());
+                continue;
+            }
+
+            // Add Device <-> Port attachment
+            PortImpl portImpl = getPortImpl(port);
+            portImpl.addDevice(device);
+            deviceImpl.addAttachmentPoint(port);
+            attachmentFound = true;
+        }
+
+        // Update the device in the Network Graph
+        if (attachmentFound) {
+            log.debug("Storing the info into networkGraph. mac {}", deviceEvent.getMac());
+            networkGraph.putDevice(device);
+            apiAddedDeviceEvents.add(deviceEvent);
+        }
     }
 
     /**
      * Remove a device from the Network Graph.
-     *
+     * <p/>
      * TODO: Device-related work is incomplete.
      *
      * @param deviceEvent the Device Event with the device to remove.
      */
     private void removeDevice(DeviceEvent deviceEvent) {
-	Device device = networkGraph.getDeviceByMac(deviceEvent.getMac());
-	if (device == null) {
-	    log.warn("Device {} already removed, ignoring", deviceEvent);
-	    return;
-	}
-	DeviceImpl deviceImpl = getDeviceImpl(device);
+        Device device = networkGraph.getDeviceByMac(deviceEvent.getMac());
+        if (device == null) {
+            log.warn("Device {} already removed, ignoring", deviceEvent);
+            return;
+        }
+        DeviceImpl deviceImpl = getDeviceImpl(device);
 
-	// Process each attachment point
-	for (SwitchPort swp : deviceEvent.getAttachmentPoints()) {
-	    // Attached Ports must exist
-	    Port port = networkGraph.getPort(swp.dpid, swp.number);
-	    if (port == null) {
-		log.warn("Port for the attachment point {} did not exist. skipping attachment point mutation", swp);
-		continue;
-	    }
+        // Process each attachment point
+        for (SwitchPort swp : deviceEvent.getAttachmentPoints()) {
+            // Attached Ports must exist
+            Port port = networkGraph.getPort(swp.dpid, swp.number);
+            if (port == null) {
+                log.warn("Port for the attachment point {} did not exist. skipping attachment point mutation", swp);
+                continue;
+            }
 
-	    // Remove Device <-> Port attachment
-	    PortImpl portImpl = getPortImpl(port);
-	    portImpl.removeDevice(device);
-	    deviceImpl.removeAttachmentPoint(port);
-	}
+            // Remove Device <-> Port attachment
+            PortImpl portImpl = getPortImpl(port);
+            portImpl.removeDevice(device);
+            deviceImpl.removeAttachmentPoint(port);
+        }
 
-	networkGraph.removeDevice(device);
-	apiRemovedDeviceEvents.add(deviceEvent);
+        networkGraph.removeDevice(device);
+        apiRemovedDeviceEvents.add(deviceEvent);
     }
 
     /**
@@ -1088,10 +1086,10 @@
      * @return the SwitchImpl-casted switch implementation.
      */
     private SwitchImpl getSwitchImpl(Switch sw) {
-	if (sw instanceof SwitchImpl) {
-	    return (SwitchImpl)sw;
-	}
-	throw new ClassCastException("SwitchImpl expected, but found: " + sw);
+        if (sw instanceof SwitchImpl) {
+            return (SwitchImpl) sw;
+        }
+        throw new ClassCastException("SwitchImpl expected, but found: " + sw);
     }
 
     /**
@@ -1101,10 +1099,10 @@
      * @return the PortImpl-casted port implementation.
      */
     private PortImpl getPortImpl(Port port) {
-	if (port instanceof PortImpl) {
-	    return (PortImpl)port;
-	}
-	throw new ClassCastException("PortImpl expected, but found: " + port);
+        if (port instanceof PortImpl) {
+            return (PortImpl) port;
+        }
+        throw new ClassCastException("PortImpl expected, but found: " + port);
     }
 
     /**
@@ -1114,10 +1112,10 @@
      * @return the LinkImpl-casted link implementation.
      */
     private LinkImpl getLinkImpl(Link link) {
-	if (link instanceof LinkImpl) {
-	    return (LinkImpl)link;
-	}
-	throw new ClassCastException("LinkImpl expected, but found: " + link);
+        if (link instanceof LinkImpl) {
+            return (LinkImpl) link;
+        }
+        throw new ClassCastException("LinkImpl expected, but found: " + link);
     }
 
     /**
@@ -1127,10 +1125,10 @@
      * @return the DeviceImpl-casted device implementation.
      */
     private DeviceImpl getDeviceImpl(Device device) {
-	if (device instanceof DeviceImpl) {
-	    return (DeviceImpl)device;
-	}
-	throw new ClassCastException("DeviceImpl expected, but found: " + device);
+        if (device instanceof DeviceImpl) {
+            return (DeviceImpl) device;
+        }
+        throw new ClassCastException("DeviceImpl expected, but found: " + device);
     }
 
     /**
@@ -1140,60 +1138,60 @@
      * the whole topology.
      */
     private Collection<EventEntry<TopologyEvent>> readWholeTopologyFromDB() {
-	Collection<EventEntry<TopologyEvent>> collection =
-	    new LinkedList<EventEntry<TopologyEvent>>();
+        Collection<EventEntry<TopologyEvent>> collection =
+                new LinkedList<EventEntry<TopologyEvent>>();
 
-	// XXX May need to clear whole topology first, depending on
-	// how we initially subscribe to replication events
+        // XXX May need to clear whole topology first, depending on
+        // how we initially subscribe to replication events
 
-	// Add all active switches
-	for (KVSwitch sw : KVSwitch.getAllSwitches()) {
-	    if (sw.getStatus() != KVSwitch.STATUS.ACTIVE) {
-		continue;
-	    }
+        // Add all active switches
+        for (KVSwitch sw : KVSwitch.getAllSwitches()) {
+            if (sw.getStatus() != KVSwitch.STATUS.ACTIVE) {
+                continue;
+            }
 
-	    SwitchEvent switchEvent = new SwitchEvent(sw.getDpid());
-	    TopologyEvent topologyEvent = new TopologyEvent(switchEvent);
-	    EventEntry<TopologyEvent> eventEntry =
-		new EventEntry<TopologyEvent>(EventEntry.Type.ENTRY_ADD,
-					      topologyEvent);
-	    collection.add(eventEntry);
-	}
+            SwitchEvent switchEvent = new SwitchEvent(sw.getDpid());
+            TopologyEvent topologyEvent = new TopologyEvent(switchEvent);
+            EventEntry<TopologyEvent> eventEntry =
+                    new EventEntry<TopologyEvent>(EventEntry.Type.ENTRY_ADD,
+                            topologyEvent);
+            collection.add(eventEntry);
+        }
 
-	// Add all active ports
-	for (KVPort p : KVPort.getAllPorts()) {
-	    if (p.getStatus() != KVPort.STATUS.ACTIVE) {
-		continue;
-	    }
+        // Add all active ports
+        for (KVPort p : KVPort.getAllPorts()) {
+            if (p.getStatus() != KVPort.STATUS.ACTIVE) {
+                continue;
+            }
 
-	    PortEvent portEvent = new PortEvent(p.getDpid(), p.getNumber());
-	    TopologyEvent topologyEvent = new TopologyEvent(portEvent);
-	    EventEntry<TopologyEvent> eventEntry =
-		new EventEntry<TopologyEvent>(EventEntry.Type.ENTRY_ADD,
-					      topologyEvent);
-	    collection.add(eventEntry);
-	}
+            PortEvent portEvent = new PortEvent(p.getDpid(), p.getNumber());
+            TopologyEvent topologyEvent = new TopologyEvent(portEvent);
+            EventEntry<TopologyEvent> eventEntry =
+                    new EventEntry<TopologyEvent>(EventEntry.Type.ENTRY_ADD,
+                            topologyEvent);
+            collection.add(eventEntry);
+        }
 
-	// TODO Is Device going to be in DB? If so, read from DB.
-	//	for (KVDevice d : KVDevice.getAllDevices()) {
-	//	    DeviceEvent devEvent = new DeviceEvent( MACAddress.valueOf(d.getMac()) );
-	//	    for (byte[] portId : d.getAllPortIds() ) {
-	//		devEvent.addAttachmentPoint( new SwitchPort( KVPort.getDpidFromKey(portId), KVPort.getNumberFromKey(portId) ));
-	//	    }
-	//	}
+        // TODO Is Device going to be in DB? If so, read from DB.
+        //      for (KVDevice d : KVDevice.getAllDevices()) {
+        //          DeviceEvent devEvent = new DeviceEvent( MACAddress.valueOf(d.getMac()) );
+        //          for (byte[] portId : d.getAllPortIds() ) {
+        //              devEvent.addAttachmentPoint( new SwitchPort( KVPort.getDpidFromKey(portId), KVPort.getNumberFromKey(portId) ));
+        //          }
+        //      }
 
-	for (KVLink l : KVLink.getAllLinks()) {
-	    LinkEvent linkEvent = new LinkEvent(l.getSrc().dpid,
-						l.getSrc().number,
-						l.getDst().dpid,
-						l.getDst().number);
-	    TopologyEvent topologyEvent = new TopologyEvent(linkEvent);
-	    EventEntry<TopologyEvent> eventEntry =
-		new EventEntry<TopologyEvent>(EventEntry.Type.ENTRY_ADD,
-					      topologyEvent);
-	    collection.add(eventEntry);
-	}
+        for (KVLink l : KVLink.getAllLinks()) {
+            LinkEvent linkEvent = new LinkEvent(l.getSrc().dpid,
+                    l.getSrc().number,
+                    l.getDst().dpid,
+                    l.getDst().number);
+            TopologyEvent topologyEvent = new TopologyEvent(linkEvent);
+            EventEntry<TopologyEvent> eventEntry =
+                    new EventEntry<TopologyEvent>(EventEntry.Type.ENTRY_ADD,
+                            topologyEvent);
+            collection.add(eventEntry);
+        }
 
-	return collection;
+        return collection;
     }
 }
diff --git a/src/main/java/net/onrc/onos/core/topology/serializers/LinkSerializer.java b/src/main/java/net/onrc/onos/core/topology/serializers/LinkSerializer.java
index 93bce90..61a3b34 100644
--- a/src/main/java/net/onrc/onos/core/topology/serializers/LinkSerializer.java
+++ b/src/main/java/net/onrc/onos/core/topology/serializers/LinkSerializer.java
@@ -12,24 +12,24 @@
 
 public class LinkSerializer extends SerializerBase<Link> {
 
-	public LinkSerializer() {
-		super(Link.class);
-	}
+    public LinkSerializer() {
+        super(Link.class);
+    }
 
-	@Override
-	public void serialize(Link link, JsonGenerator jsonGenerator, 
-			SerializerProvider serializerProvider)
-			throws IOException, JsonGenerationException {
-		jsonGenerator.writeStartObject();
-		jsonGenerator.writeStringField("src-switch", 
-				HexString.toHexString(link.getSrcSwitch().getDpid()));
-		jsonGenerator.writeNumberField("src-port", 
-				link.getSrcPort().getNumber());
-		jsonGenerator.writeStringField("dst-switch", 
-				HexString.toHexString(link.getDstSwitch().getDpid()));
-		jsonGenerator.writeNumberField("dst-port", 
-				link.getDstPort().getNumber());
-		jsonGenerator.writeEndObject();
-	}
+    @Override
+    public void serialize(Link link, JsonGenerator jsonGenerator,
+                          SerializerProvider serializerProvider)
+            throws IOException, JsonGenerationException {
+        jsonGenerator.writeStartObject();
+        jsonGenerator.writeStringField("src-switch",
+                HexString.toHexString(link.getSrcSwitch().getDpid()));
+        jsonGenerator.writeNumberField("src-port",
+                link.getSrcPort().getNumber());
+        jsonGenerator.writeStringField("dst-switch",
+                HexString.toHexString(link.getDstSwitch().getDpid()));
+        jsonGenerator.writeNumberField("dst-port",
+                link.getDstPort().getNumber());
+        jsonGenerator.writeEndObject();
+    }
 
 }
diff --git a/src/main/java/net/onrc/onos/core/topology/serializers/PortSerializer.java b/src/main/java/net/onrc/onos/core/topology/serializers/PortSerializer.java
index 25e64d0..ae75dff 100644
--- a/src/main/java/net/onrc/onos/core/topology/serializers/PortSerializer.java
+++ b/src/main/java/net/onrc/onos/core/topology/serializers/PortSerializer.java
@@ -11,21 +11,21 @@
 
 public class PortSerializer extends SerializerBase<Port> {
 
-	public PortSerializer() {
-		super(Port.class);
-	}
+    public PortSerializer() {
+        super(Port.class);
+    }
 
-	@Override
-	public void serialize(Port port, JsonGenerator jsonGenerator, 
-			SerializerProvider serializerProvider)
-			throws IOException, JsonProcessingException {
-		jsonGenerator.writeStartObject();
-		jsonGenerator.writeStringField("state", "ACTIVE");
-		jsonGenerator.writeNumberField("number", port.getNumber());
-		jsonGenerator.writeStringField("desc", port.getDescription());
-		jsonGenerator.writeArrayFieldStart("devices");
-		jsonGenerator.writeEndArray();
-		jsonGenerator.writeEndObject();
-	}
+    @Override
+    public void serialize(Port port, JsonGenerator jsonGenerator,
+                          SerializerProvider serializerProvider)
+            throws IOException, JsonProcessingException {
+        jsonGenerator.writeStartObject();
+        jsonGenerator.writeStringField("state", "ACTIVE");
+        jsonGenerator.writeNumberField("number", port.getNumber());
+        jsonGenerator.writeStringField("desc", port.getDescription());
+        jsonGenerator.writeArrayFieldStart("devices");
+        jsonGenerator.writeEndArray();
+        jsonGenerator.writeEndObject();
+    }
 
 }
diff --git a/src/main/java/net/onrc/onos/core/topology/serializers/SwitchSerializer.java b/src/main/java/net/onrc/onos/core/topology/serializers/SwitchSerializer.java
index e36d35c..00bdcad 100644
--- a/src/main/java/net/onrc/onos/core/topology/serializers/SwitchSerializer.java
+++ b/src/main/java/net/onrc/onos/core/topology/serializers/SwitchSerializer.java
@@ -13,24 +13,24 @@
 
 public class SwitchSerializer extends SerializerBase<Switch> {
 
-	public SwitchSerializer() {
-		super(Switch.class);
-	}
+    public SwitchSerializer() {
+        super(Switch.class);
+    }
 
-	@Override
-	public void serialize(Switch sw, JsonGenerator jsonGenerator,
-			SerializerProvider serializerProvider) throws IOException,
-			JsonProcessingException {
-		
-		jsonGenerator.writeStartObject();
-		jsonGenerator.writeStringField("dpid", HexString.toHexString(sw.getDpid()));
-		jsonGenerator.writeStringField("state", "ACTIVE");
-		jsonGenerator.writeArrayFieldStart("ports");
-		for (Port port : sw.getPorts()) {
-			jsonGenerator.writeObject(port);
-		}
-		jsonGenerator.writeEndArray();
-		jsonGenerator.writeEndObject();
-	}
+    @Override
+    public void serialize(Switch sw, JsonGenerator jsonGenerator,
+                          SerializerProvider serializerProvider) throws IOException,
+            JsonProcessingException {
+
+        jsonGenerator.writeStartObject();
+        jsonGenerator.writeStringField("dpid", HexString.toHexString(sw.getDpid()));
+        jsonGenerator.writeStringField("state", "ACTIVE");
+        jsonGenerator.writeArrayFieldStart("ports");
+        for (Port port : sw.getPorts()) {
+            jsonGenerator.writeObject(port);
+        }
+        jsonGenerator.writeEndArray();
+        jsonGenerator.writeEndObject();
+    }
 
 }
diff --git a/src/main/java/net/onrc/onos/core/topology/web/DatastoreLinksResource.java b/src/main/java/net/onrc/onos/core/topology/web/DatastoreLinksResource.java
index 4837055..0f3b85c 100644
--- a/src/main/java/net/onrc/onos/core/topology/web/DatastoreLinksResource.java
+++ b/src/main/java/net/onrc/onos/core/topology/web/DatastoreLinksResource.java
@@ -7,8 +7,8 @@
 
 public class DatastoreLinksResource extends ServerResource {
 
-	@Get("json")
-	public Iterable<KVLink> retrieve() {
-		return KVLink.getAllLinks();
-	}
+    @Get("json")
+    public Iterable<KVLink> retrieve() {
+        return KVLink.getAllLinks();
+    }
 }
diff --git a/src/main/java/net/onrc/onos/core/topology/web/DatastorePortsResource.java b/src/main/java/net/onrc/onos/core/topology/web/DatastorePortsResource.java
index 46eaf1a..2ffb476 100644
--- a/src/main/java/net/onrc/onos/core/topology/web/DatastorePortsResource.java
+++ b/src/main/java/net/onrc/onos/core/topology/web/DatastorePortsResource.java
@@ -7,8 +7,8 @@
 
 public class DatastorePortsResource extends ServerResource {
 
-	@Get("json")
-	public Iterable<KVPort> retrieve() {
-		return KVPort.getAllPorts();
-	}
+    @Get("json")
+    public Iterable<KVPort> retrieve() {
+        return KVPort.getAllPorts();
+    }
 }
diff --git a/src/main/java/net/onrc/onos/core/topology/web/DatastoreSwitchesResource.java b/src/main/java/net/onrc/onos/core/topology/web/DatastoreSwitchesResource.java
index fe2cfcd..9459764 100644
--- a/src/main/java/net/onrc/onos/core/topology/web/DatastoreSwitchesResource.java
+++ b/src/main/java/net/onrc/onos/core/topology/web/DatastoreSwitchesResource.java
@@ -6,10 +6,10 @@
 import org.restlet.resource.ServerResource;
 
 public class DatastoreSwitchesResource extends ServerResource {
-	
-	@Get("json")
-	public Iterable<KVSwitch> retrieve() {
-		return KVSwitch.getAllSwitches();
-	}
+
+    @Get("json")
+    public Iterable<KVSwitch> retrieve() {
+        return KVSwitch.getAllSwitches();
+    }
 
 }
diff --git a/src/main/java/net/onrc/onos/core/topology/web/NetworkGraphLinksResource.java b/src/main/java/net/onrc/onos/core/topology/web/NetworkGraphLinksResource.java
index 5886aa5..8d4bc93 100644
--- a/src/main/java/net/onrc/onos/core/topology/web/NetworkGraphLinksResource.java
+++ b/src/main/java/net/onrc/onos/core/topology/web/NetworkGraphLinksResource.java
@@ -15,29 +15,29 @@
 import org.slf4j.LoggerFactory;
 
 public class NetworkGraphLinksResource extends ServerResource {
-	
-	private static final Logger log = LoggerFactory.getLogger(NetworkGraphLinksResource.class);
 
-	@Get("json")
-	public String retrieve() {
-		INetworkGraphService networkGraphService = (INetworkGraphService) getContext().getAttributes().
-				get(INetworkGraphService.class.getCanonicalName());
-		
-		NetworkGraph graph = networkGraphService.getNetworkGraph();
+    private static final Logger log = LoggerFactory.getLogger(NetworkGraphLinksResource.class);
 
-		ObjectMapper mapper = new ObjectMapper();
-		SimpleModule module = new SimpleModule("module", new Version(1, 0, 0, null));
-		module.addSerializer(new LinkSerializer());
-		mapper.registerModule(module);
-		
-		try {
-			graph.acquireReadLock();
-			return mapper.writeValueAsString(graph.getLinks());
-		} catch (IOException e) {
-			log.error("Error writing link list to JSON", e);
-			return "";
-		} finally {
-		    graph.releaseReadLock();
-		}
-	}
+    @Get("json")
+    public String retrieve() {
+        INetworkGraphService networkGraphService = (INetworkGraphService) getContext().getAttributes().
+                get(INetworkGraphService.class.getCanonicalName());
+
+        NetworkGraph graph = networkGraphService.getNetworkGraph();
+
+        ObjectMapper mapper = new ObjectMapper();
+        SimpleModule module = new SimpleModule("module", new Version(1, 0, 0, null));
+        module.addSerializer(new LinkSerializer());
+        mapper.registerModule(module);
+
+        try {
+            graph.acquireReadLock();
+            return mapper.writeValueAsString(graph.getLinks());
+        } catch (IOException e) {
+            log.error("Error writing link list to JSON", e);
+            return "";
+        } finally {
+            graph.releaseReadLock();
+        }
+    }
 }
diff --git a/src/main/java/net/onrc/onos/core/topology/web/NetworkGraphShortestPathResource.java b/src/main/java/net/onrc/onos/core/topology/web/NetworkGraphShortestPathResource.java
index 1d4164b..6650efc 100644
--- a/src/main/java/net/onrc/onos/core/topology/web/NetworkGraphShortestPathResource.java
+++ b/src/main/java/net/onrc/onos/core/topology/web/NetworkGraphShortestPathResource.java
@@ -28,54 +28,54 @@
 
     @Get("json")
     public String retrieve() {
-	INetworkGraphService networkGraphService =
-	    (INetworkGraphService)getContext().getAttributes().
-	    get(INetworkGraphService.class.getCanonicalName());
+        INetworkGraphService networkGraphService =
+                (INetworkGraphService) getContext().getAttributes().
+                        get(INetworkGraphService.class.getCanonicalName());
 
-	NetworkGraph graph = networkGraphService.getNetworkGraph();
+        NetworkGraph graph = networkGraphService.getNetworkGraph();
 
-	ObjectMapper mapper = new ObjectMapper();
-	SimpleModule module = new SimpleModule("module", new Version(1, 0, 0, null));
-	module.addSerializer(new LinkSerializer());
-	mapper.registerModule(module);
+        ObjectMapper mapper = new ObjectMapper();
+        SimpleModule module = new SimpleModule("module", new Version(1, 0, 0, null));
+        module.addSerializer(new LinkSerializer());
+        mapper.registerModule(module);
 
-	//
-	// Fetch the attributes
-	//
-	String srcDpidStr = (String)getRequestAttributes().get("src-dpid");
-	String dstDpidStr = (String)getRequestAttributes().get("dst-dpid");
-	Dpid srcDpid = new Dpid(srcDpidStr);
-	Dpid dstDpid = new Dpid(dstDpidStr);
-	log.debug("Getting Shortest Path {}--{}", srcDpidStr, dstDpidStr);
+        //
+        // Fetch the attributes
+        //
+        String srcDpidStr = (String) getRequestAttributes().get("src-dpid");
+        String dstDpidStr = (String) getRequestAttributes().get("dst-dpid");
+        Dpid srcDpid = new Dpid(srcDpidStr);
+        Dpid dstDpid = new Dpid(dstDpidStr);
+        log.debug("Getting Shortest Path {}--{}", srcDpidStr, dstDpidStr);
 
-	//
-	// Do the Shortest Path computation and return the result: list of
-	// links.
-	//
-	try {
-	    graph.acquireReadLock();
-	    Switch srcSwitch = graph.getSwitch(srcDpid.value());
-	    Switch dstSwitch = graph.getSwitch(dstDpid.value());
-	    if ((srcSwitch == null) || (dstSwitch == null))
-		return "";
-	    ConstrainedBFSTree bfsTree = new ConstrainedBFSTree(srcSwitch);
-	    Path path = bfsTree.getPath(dstSwitch);
-	    List<Link> links = new LinkedList<>();
-	    for (LinkEvent linkEvent : path) {
-		Link link = graph.getLink(linkEvent.getSrc().getDpid(),
-					  linkEvent.getSrc().getNumber(),
-					  linkEvent.getDst().getDpid(),
-					  linkEvent.getDst().getNumber());
-		if (link == null)
-		    return "";
-		links.add(link);
-	    }
-	    return mapper.writeValueAsString(links);
-	} catch (IOException e) {
-	    log.error("Error writing Shortest Path to JSON", e);
-	    return "";
-	} finally {
-	    graph.releaseReadLock();
-	}
+        //
+        // Do the Shortest Path computation and return the result: list of
+        // links.
+        //
+        try {
+            graph.acquireReadLock();
+            Switch srcSwitch = graph.getSwitch(srcDpid.value());
+            Switch dstSwitch = graph.getSwitch(dstDpid.value());
+            if ((srcSwitch == null) || (dstSwitch == null))
+                return "";
+            ConstrainedBFSTree bfsTree = new ConstrainedBFSTree(srcSwitch);
+            Path path = bfsTree.getPath(dstSwitch);
+            List<Link> links = new LinkedList<>();
+            for (LinkEvent linkEvent : path) {
+                Link link = graph.getLink(linkEvent.getSrc().getDpid(),
+                        linkEvent.getSrc().getNumber(),
+                        linkEvent.getDst().getDpid(),
+                        linkEvent.getDst().getNumber());
+                if (link == null)
+                    return "";
+                links.add(link);
+            }
+            return mapper.writeValueAsString(links);
+        } catch (IOException e) {
+            log.error("Error writing Shortest Path to JSON", e);
+            return "";
+        } finally {
+            graph.releaseReadLock();
+        }
     }
 }
diff --git a/src/main/java/net/onrc/onos/core/topology/web/NetworkGraphSwitchesResource.java b/src/main/java/net/onrc/onos/core/topology/web/NetworkGraphSwitchesResource.java
index 059771f..3a053e5 100644
--- a/src/main/java/net/onrc/onos/core/topology/web/NetworkGraphSwitchesResource.java
+++ b/src/main/java/net/onrc/onos/core/topology/web/NetworkGraphSwitchesResource.java
@@ -16,30 +16,30 @@
 import org.slf4j.LoggerFactory;
 
 public class NetworkGraphSwitchesResource extends ServerResource {
-	
-	private static final Logger log = LoggerFactory.getLogger(NetworkGraphSwitchesResource.class);
 
-	@Get("json")
-	public String retrieve() {
-		INetworkGraphService networkGraphService = (INetworkGraphService) getContext().getAttributes().
-				get(INetworkGraphService.class.getCanonicalName());
-		
-		NetworkGraph graph = networkGraphService.getNetworkGraph();
-		
-		ObjectMapper mapper = new ObjectMapper();
-		SimpleModule module = new SimpleModule("module", new Version(1, 0, 0, null));
-		module.addSerializer(new SwitchSerializer());
-		module.addSerializer(new PortSerializer());
-		mapper.registerModule(module);
-		
-		try {
-			graph.acquireReadLock();
-			return mapper.writeValueAsString(graph.getSwitches());
-		} catch (IOException e) {
-			log.error("Error writing switch list to JSON", e);
-			return "";
-		} finally {
-			graph.releaseReadLock();
-		}
-	}
+    private static final Logger log = LoggerFactory.getLogger(NetworkGraphSwitchesResource.class);
+
+    @Get("json")
+    public String retrieve() {
+        INetworkGraphService networkGraphService = (INetworkGraphService) getContext().getAttributes().
+                get(INetworkGraphService.class.getCanonicalName());
+
+        NetworkGraph graph = networkGraphService.getNetworkGraph();
+
+        ObjectMapper mapper = new ObjectMapper();
+        SimpleModule module = new SimpleModule("module", new Version(1, 0, 0, null));
+        module.addSerializer(new SwitchSerializer());
+        module.addSerializer(new PortSerializer());
+        mapper.registerModule(module);
+
+        try {
+            graph.acquireReadLock();
+            return mapper.writeValueAsString(graph.getSwitches());
+        } catch (IOException e) {
+            log.error("Error writing switch list to JSON", e);
+            return "";
+        } finally {
+            graph.releaseReadLock();
+        }
+    }
 }
diff --git a/src/main/java/net/onrc/onos/core/topology/web/NetworkGraphWebRoutable.java b/src/main/java/net/onrc/onos/core/topology/web/NetworkGraphWebRoutable.java
index c6791e5..8f32f8a 100644
--- a/src/main/java/net/onrc/onos/core/topology/web/NetworkGraphWebRoutable.java
+++ b/src/main/java/net/onrc/onos/core/topology/web/NetworkGraphWebRoutable.java
@@ -8,33 +8,33 @@
 
 public class NetworkGraphWebRoutable implements RestletRoutable {
 
-	@Override
-	public Restlet getRestlet(Context context) {
-		Router router = new Router(context);
-		// leaving old path there for compatibility
-		router.attach("/rc/switches/json", DatastoreSwitchesResource.class);
-		router.attach("/rc/links/json", DatastoreLinksResource.class);
-		router.attach("/rc/ports/json", DatastorePortsResource.class);
+    @Override
+    public Restlet getRestlet(Context context) {
+        Router router = new Router(context);
+        // leaving old path there for compatibility
+        router.attach("/rc/switches/json", DatastoreSwitchesResource.class);
+        router.attach("/rc/links/json", DatastoreLinksResource.class);
+        router.attach("/rc/ports/json", DatastorePortsResource.class);
 
-                // debug API to dump datastore content
-                router.attach("/ds/switches/json", DatastoreSwitchesResource.class);
-                router.attach("/ds/links/json", DatastoreLinksResource.class);
-                router.attach("/ds/ports/json", DatastorePortsResource.class);
+        // debug API to dump datastore content
+        router.attach("/ds/switches/json", DatastoreSwitchesResource.class);
+        router.attach("/ds/links/json", DatastoreLinksResource.class);
+        router.attach("/ds/ports/json", DatastorePortsResource.class);
 
-		router.attach("/ng/switches/json", NetworkGraphSwitchesResource.class);
-		router.attach("/ng/links/json", NetworkGraphLinksResource.class);
-		router.attach("/ng/shortest-path/{src-dpid}/{dst-dpid}/json", NetworkGraphShortestPathResource.class);
-		
-		// Old URLs for compatibility
-		router.attach("/topology/switches/json", NetworkGraphSwitchesResource.class);
-		router.attach("/topology/links/json", NetworkGraphLinksResource.class);
-		
-		return router;
-	}
+        router.attach("/ng/switches/json", NetworkGraphSwitchesResource.class);
+        router.attach("/ng/links/json", NetworkGraphLinksResource.class);
+        router.attach("/ng/shortest-path/{src-dpid}/{dst-dpid}/json", NetworkGraphShortestPathResource.class);
 
-	@Override
-	public String basePath() {
-		return "/wm/onos";
-	}
+        // Old URLs for compatibility
+        router.attach("/topology/switches/json", NetworkGraphSwitchesResource.class);
+        router.attach("/topology/links/json", NetworkGraphLinksResource.class);
+
+        return router;
+    }
+
+    @Override
+    public String basePath() {
+        return "/wm/onos";
+    }
 
 }