Network Graph Refactoring: Northbound API cleanup
 * Renamed/shortened methods:
   Link.getSourcePort() -> getSrcPort()
   Link.getDestinationPort() -> getDstPort()
   Link.getSourceSwitch() -> getSrcSwitch()
   Link.getDestinationSwitch() -> getDstSwitch()

 * Added Javadoc comments

 * Removed deprecated and unused methods:
   Link.getSourceSwitchDpid()
   Link.getSorcePortNumber()
   Link.getDestinationSwitchDpid()
   Link.getDestinationPortNumber()
   NetworkGraph.getOutgoingLinksFromSwitch()
   NetworkGraph.getIncomingLinksFromSwitch()

 * Moved method LinkEvent.getLink(NetworkGraph graph)
   to NetworkGraph.getLink()

Change-Id: Ibedba53fc6cd04d77f508ee67d41b2cfa515d3fc
diff --git a/src/main/java/net/onrc/onos/ofcontroller/networkgraph/Link.java b/src/main/java/net/onrc/onos/ofcontroller/networkgraph/Link.java
index 4fd53af..996997a 100644
--- a/src/main/java/net/onrc/onos/ofcontroller/networkgraph/Link.java
+++ b/src/main/java/net/onrc/onos/ofcontroller/networkgraph/Link.java
@@ -8,25 +8,59 @@
  *
  */
 public interface Link {
-	public Port getSourcePort();
-	public Port getDestinationPort();
-	public Switch getSourceSwitch();
-	public Switch getDestinationSwitch();
+    /**
+     * Get the source switch for the link.
+     *
+     * @return the source switch for the link.
+     */
+    public Switch getSrcSwitch();
 
-	public long getLastSeenTime();
+    /**
+     * Get the source port for the link.
+     *
+     * @return the source port for the link.
+     */
+    public Port getSrcPort();
 
-	public int getCost();
-	public Double getCapacity();
+    /**
+     * Get the destination switch for the link.
+     *
+     * @return the destination switch for the link.
+     */
+    public Switch getDstSwitch();
 
-	// Not sure if we want to expose these northbound
-	// Toshi: I think these are unnecessary because we can get them
-	// Toshi: like "this.getSourcePort().getSwitch()" etc.
-	@Deprecated
-	public Long getSourceSwitchDpid();
-	@Deprecated
-	public Long getSourcePortNumber();
-	@Deprecated
-	public Long getDestinationSwitchDpid();
-	@Deprecated
-	public Long getDestinationPortNumber();
+    /**
+     * Get the destination port for the link.
+     *
+     * @return the destination port for the link.
+     */
+    public Port getDstPort();
+
+    /**
+     * Get the last seen time for the link.
+     *
+     * TODO: Not implemented yet.
+     * TODO: what is the time definition?
+     *
+     * @return the last seen time for the link.
+     */
+    public long getLastSeenTime();
+
+    /**
+     * Get the link cost.
+     *
+     * TODO: What is the unit?
+     *
+     * @param return the link cost.
+     */
+    public int getCost();
+
+    /**
+     * Get the link capacity.
+     *
+     * TODO: What is the unit?
+     *
+     * @return the link capacity.
+     */
+    public Double getCapacity();
 }