diff --git a/src/main/java/net/onrc/onos/util/GraphDBConnection.java b/src/main/java/net/onrc/onos/util/GraphDBConnection.java
index 7ea0ab8..e25a0c6 100644
--- a/src/main/java/net/onrc/onos/util/GraphDBConnection.java
+++ b/src/main/java/net/onrc/onos/util/GraphDBConnection.java
@@ -12,165 +12,159 @@
 import com.tinkerpop.blueprints.util.wrappers.event.EventTransactionalGraph;
 import com.tinkerpop.frames.FramedGraph;
 
-public class GraphDBConnection {
+public class GraphDBConnection implements IDBConnection {
 	public enum Transaction {
-		COMMIT,
-		ROLLBACK
+		COMMIT, ROLLBACK
 	}
+
 	public enum GenerateEvent {
-		TRUE,
-		FALSE
+		TRUE, FALSE
 	}
+
 	class TransactionHandle {
 		protected TransactionalGraph tr;
+
 		public void create() {
-			tr = graph.newTransaction();			
+			tr = graph.newTransaction();
 		}
 	}
-	protected static Logger log = LoggerFactory.getLogger(GraphDBConnection.class);
-	private static GraphDBConnection singleton = new GraphDBConnection( );
+
+	protected static Logger log = LoggerFactory
+			.getLogger(GraphDBConnection.class);
+	private static GraphDBConnection singleton = new GraphDBConnection();
 	private static TitanGraph graph;
 	private static EventTransactionalGraph<TitanGraph> eg;
-	private static GraphDBUtils utils;
 	private static String configFile;
 
-	   
-	   /* A private Constructor prevents any other 
-	    * class from instantiating.
-	    */
-	   private GraphDBConnection(){ }
-	   
-	   /* Static 'instance' method */
-	   public static synchronized GraphDBConnection getInstance(final String conf) {
-		   if (GraphDBConnection.configFile == null || GraphDBConnection.configFile.isEmpty()) {
-			   GraphDBConnection.configFile = conf;
-			   log.debug("GraphDBConnection::Setting Config File {}", GraphDBConnection.configFile);
-		   }
-		   if (!GraphDBConnection.configFile.isEmpty() && 
-				   (graph == null||graph.isOpen() == Boolean.FALSE)) {
-		        graph = TitanFactory.open(GraphDBConnection.configFile);		        
-		        // FIXME: Creation on Indexes should be done only once
-		        Set<String> s = graph.getIndexedKeys(Vertex.class);
-		        if (!s.contains("dpid")) {
-		           graph.createKeyIndex("dpid", Vertex.class);
-		        }
-		        if (!s.contains("type")) {
-		        	graph.createKeyIndex("type", Vertex.class);
-		        }
-		        if (!s.contains("dl_address")) {
-		        	graph.createKeyIndex("dl_address", Vertex.class);
-		        }
-		        if (!s.contains("flow_id")) {
-		        	graph.createKeyIndex("flow_id", Vertex.class);
-		        }
-		        if (!s.contains("flow_entry_id")) {
-		        	graph.createKeyIndex("flow_entry_id",
-						     Vertex.class);
-		        }
-		        if (!s.contains("switch_state")) {
-		        	graph.createKeyIndex("switch_state",
-						     Vertex.class);
-		        }
-		        graph.commit();
-		        eg = new EventTransactionalGraph<TitanGraph>(graph);
-		   }		   
-		   if (utils == null) {
-			   utils = new GraphDBUtils();
-		   }
-	      return singleton;
-	   }
-	   
-	   public IDBUtils utils() {
-		   return utils;
-	   }
-	   
-	   public FramedGraph<TitanGraph> getFramedGraph() {
-	   
-		   	if (isValid()) {
-		   		FramedGraph<TitanGraph> fg = new FramedGraph<TitanGraph>(graph);
-		   		return fg;
-		   	} else {
-		   		log.error("new FramedGraph failed");
-		   		return null;
-		   	}
-	   }
-	   
-	   protected EventTransactionalGraph<TitanGraph> getEventGraph() {
-		   
-		   	if (isValid()) {		   		
-		   		return eg;
-		   	} else {
-		   		return null;
-		   	}
-	   }
-	   
-	   public void addEventListener(final LocalGraphChangedListener listener) {		   
-		   EventTransactionalGraph<TitanGraph> eg = this.getEventGraph();
-		   eg.addListener(listener);
-		   log.debug("Registered listener {}",listener.getClass());
-	   }
-	   
-	   public Boolean isValid() {
-		   
-		   return (graph != null||graph.isOpen());
-	   }
-	   
-	   public void startTx() {
-		   
-		   
-	   }
-	   
-	   public void endTx(Transaction tx) {
-		   try {
-			   switch (tx) {
-			   case COMMIT:
-				   graph.commit();
-			   case ROLLBACK:
-				   graph.rollback();
-			   }
-		   } catch (Exception e) {
-			   // TODO Auto-generated catch block
-			   log.error("{}",e.toString());
-		   }
-	   }
-	   
-	   public void endTx(TransactionHandle tr, Transaction tx) {
-		   switch (tx) {
-		   case COMMIT:
-			   if (tr != null && tr.tr != null) {
-				   tr.tr.commit();
-			   } else {
-				   graph.commit();
-			   }
-		   case ROLLBACK:
-			   if (tr != null && tr.tr != null) {
-				   tr.tr.rollback();
-			   } else {
-				   graph.rollback();
-			   }
-		   }
-	   }   
-	   
-	   public void endTx(Transaction tx, GenerateEvent fire) {
+	/*
+	 * A private Constructor prevents any other class from instantiating.
+	 */
+	private GraphDBConnection() {
+	}
 
-		   try {
+	/* Static 'instance' method */
+	public static synchronized GraphDBConnection getInstance(final String conf) {
+		if (GraphDBConnection.configFile == null
+				|| GraphDBConnection.configFile.isEmpty()) {
+			GraphDBConnection.configFile = conf;
+			log.debug("GraphDBConnection::Setting Config File {}",
+					GraphDBConnection.configFile);
+		}
+		if (!GraphDBConnection.configFile.isEmpty()
+				&& (graph == null || graph.isOpen() == Boolean.FALSE)) {
+			graph = TitanFactory.open(GraphDBConnection.configFile);
+			// FIXME: Creation on Indexes should be done only once
+			Set<String> s = graph.getIndexedKeys(Vertex.class);
+			if (!s.contains("dpid")) {
+				graph.createKeyIndex("dpid", Vertex.class);
+			}
+			if (!s.contains("type")) {
+				graph.createKeyIndex("type", Vertex.class);
+			}
+			if (!s.contains("dl_address")) {
+				graph.createKeyIndex("dl_address", Vertex.class);
+			}
+			if (!s.contains("flow_id")) {
+				graph.createKeyIndex("flow_id", Vertex.class);
+			}
+			if (!s.contains("flow_entry_id")) {
+				graph.createKeyIndex("flow_entry_id", Vertex.class);
+			}
+			if (!s.contains("switch_state")) {
+				graph.createKeyIndex("switch_state", Vertex.class);
+			}
+			graph.commit();
+			eg = new EventTransactionalGraph<TitanGraph>(graph);
+		}
+		return singleton;
+	}
+
+	public FramedGraph<TitanGraph> getFramedGraph() {
+
+		if (isValid()) {
+			FramedGraph<TitanGraph> fg = new FramedGraph<TitanGraph>(graph);
+			return fg;
+		} else {
+			log.error("new FramedGraph failed");
+			return null;
+		}
+	}
+
+	protected EventTransactionalGraph<TitanGraph> getEventGraph() {
+
+		if (isValid()) {
+			return eg;
+		} else {
+			return null;
+		}
+	}
+
+	public void addEventListener(final LocalGraphChangedListener listener) {
+		EventTransactionalGraph<TitanGraph> eg = this.getEventGraph();
+		eg.addListener(listener);
+		log.debug("Registered listener {}", listener.getClass());
+	}
+
+	public Boolean isValid() {
+
+		return (graph != null || graph.isOpen());
+	}
+
+	public void startTx() {
+
+	}
+
+	public void endTx(Transaction tx) {
+		try {
+			switch (tx) {
+			case COMMIT:
+				graph.commit();
+			case ROLLBACK:
+				graph.rollback();
+			}
+		} catch (Exception e) {
+			// TODO Auto-generated catch block
+			log.error("{}", e.toString());
+		}
+	}
+
+	public void endTx(TransactionHandle tr, Transaction tx) {
+		switch (tx) {
+		case COMMIT:
+			if (tr != null && tr.tr != null) {
+				tr.tr.commit();
+			} else {
+				graph.commit();
+			}
+		case ROLLBACK:
+			if (tr != null && tr.tr != null) {
+				tr.tr.rollback();
+			} else {
+				graph.rollback();
+			}
+		}
+	}
+
+	public void endTx(Transaction tx, GenerateEvent fire) {
+
+		try {
 			if (fire.equals(GenerateEvent.TRUE)) {
-				   switch (tx) {
-				   case COMMIT:
-					   eg.commit();
-				   case ROLLBACK:
-					   eg.rollback();
-				   }
-			   } else {
-					endTx(tx);   			   
-			   }
+				switch (tx) {
+				case COMMIT:
+					eg.commit();
+				case ROLLBACK:
+					eg.rollback();
+				}
+			} else {
+				endTx(tx);
+			}
 		} catch (Exception e) {
 			// TODO Auto-generated catch block
 			e.printStackTrace();
 		}
-	   }
-	   
-	   public void close() {
-		   endTx(Transaction.COMMIT);
-	   }	   
+	}
+
+	public void close() {
+		endTx(Transaction.COMMIT);
+	}
 }
diff --git a/src/main/java/net/onrc/onos/util/GraphDBUtils.java b/src/main/java/net/onrc/onos/util/GraphDBOperation.java
similarity index 76%
rename from src/main/java/net/onrc/onos/util/GraphDBUtils.java
rename to src/main/java/net/onrc/onos/util/GraphDBOperation.java
index 92befe6..a87d5f5 100644
--- a/src/main/java/net/onrc/onos/util/GraphDBUtils.java
+++ b/src/main/java/net/onrc/onos/util/GraphDBOperation.java
@@ -18,23 +18,32 @@
 import com.tinkerpop.frames.structures.FramedVertexIterable;
 import com.tinkerpop.gremlin.java.GremlinPipeline;
 
-public class GraphDBUtils implements IDBUtils {
+public class GraphDBOperation implements IDBOperation {
+	private GraphDBConnection conn;
+	
+	public GraphDBOperation(GraphDBConnection dbConnection) {
+		this.conn = dbConnection;
+	}
 	
 	@Override
-	public ISwitchObject newSwitch(GraphDBConnection conn) {
+ 	public ISwitchObject newSwitch(String dpid) {
 		FramedGraph<TitanGraph> fg = conn.getFramedGraph();	
 		ISwitchObject obj = fg.addVertex(null,ISwitchObject.class);
+		if (obj != null) {
+			obj.setType("switch");
+			obj.setDPID(dpid);
+		}
 		return obj;
 	}
 
 	@Override
-	public void removeSwitch(GraphDBConnection conn, ISwitchObject sw) {
+	public void removeSwitch(ISwitchObject sw) {
 		FramedGraph<TitanGraph> fg = conn.getFramedGraph();	
 		fg.removeVertex(sw.asVertex());		
 	}
 	
 	@Override
-	public ISwitchObject searchSwitch(GraphDBConnection conn, String dpid) {
+	public ISwitchObject searchSwitch(String dpid) {
 		// TODO Auto-generated method stub
 		FramedGraph<TitanGraph> fg = conn.getFramedGraph();
 		
@@ -44,7 +53,7 @@
 	}
 
 	@Override
-	public IDeviceObject searchDevice(GraphDBConnection conn, String macAddr) {
+	public IDeviceObject searchDevice(String macAddr) {
 		// TODO Auto-generated method stub
 		FramedGraph<TitanGraph> fg = conn.getFramedGraph();	
 		return (fg != null && fg.getVertices("dl_address",macAddr).iterator().hasNext()) ? fg.getVertices("dl_address",macAddr,
@@ -53,8 +62,8 @@
 	}
 
 	@Override
-	public IPortObject searchPort(GraphDBConnection conn, String dpid, short number) {
-		ISwitchObject sw = searchSwitch(conn, dpid);
+	public IPortObject searchPort(String dpid, short number) {
+		ISwitchObject sw = searchSwitch(dpid);
 		if (sw != null) {
 			
 			IPortObject port = null;
@@ -82,41 +91,45 @@
 	}
 
 	@Override
-	public IPortObject newPort(GraphDBConnection conn) {
+	public IPortObject newPort(Short portNumber) {
 		FramedGraph<TitanGraph> fg = conn.getFramedGraph();	
 		IPortObject obj = fg.addVertex(null,IPortObject.class);
+		if (obj != null) {
+			obj.setType("port");
+			obj.setNumber(portNumber);
+		}
 		return obj;
 	}
 	
 	@Override
-	public IDeviceObject newDevice(GraphDBConnection conn) {
+	public IDeviceObject newDevice() {
 		FramedGraph<TitanGraph> fg = conn.getFramedGraph();	
 		IDeviceObject obj = fg.addVertex(null,IDeviceObject.class);
+		if (obj != null) obj.setType("device");
 		return obj;
 	}
 	
 	@Override
-	public void removePort(GraphDBConnection conn, IPortObject port) {
+	public void removePort(IPortObject port) {
 		FramedGraph<TitanGraph> fg = conn.getFramedGraph();	
 //		EventGraph<TitanGraph> eg = conn.getEventGraph();
 		if (fg != null) fg.removeVertex(port.asVertex());		
 	}
 
 	@Override
-	public void removeDevice(GraphDBConnection conn, IDeviceObject dev) {
+	public void removeDevice(IDeviceObject dev) {
 		FramedGraph<TitanGraph> fg = conn.getFramedGraph();	
 		if (fg != null) fg.removeVertex(dev.asVertex());		
 	}
 
 	@Override
-	public Iterable<IDeviceObject> getDevices(GraphDBConnection conn) {
+	public Iterable<IDeviceObject> getDevices() {
 		FramedGraph<TitanGraph> fg = conn.getFramedGraph();	
 		return fg != null ? fg.getVertices("type","device",IDeviceObject.class) : null;
 	}
 
 	@Override
-	public IFlowPath searchFlowPath(GraphDBConnection conn,
-					FlowId flowId) {
+	public IFlowPath searchFlowPath(FlowId flowId) {
 		FramedGraph<TitanGraph> fg = conn.getFramedGraph();
 		
 		return fg.getVertices("flow_id", flowId.toString()).iterator().hasNext() ? 
@@ -125,22 +138,21 @@
 	}
 
 	@Override
-	public IFlowPath newFlowPath(GraphDBConnection conn) {
+	public IFlowPath newFlowPath() {
 		FramedGraph<TitanGraph> fg = conn.getFramedGraph();	
 		IFlowPath flowPath = fg.addVertex(null, IFlowPath.class);
+		if (flowPath != null) flowPath.setType("flow");
 		return flowPath;
 	}
 
 	@Override
-	public void removeFlowPath(GraphDBConnection conn,
-				   IFlowPath flowPath) {
+	public void removeFlowPath(IFlowPath flowPath) {
 		FramedGraph<TitanGraph> fg = conn.getFramedGraph();
 		fg.removeVertex(flowPath.asVertex());
 	}
 
 	@Override
-	public IFlowPath getFlowPathByFlowEntry(GraphDBConnection conn,
-						IFlowEntry flowEntry) {
+	public IFlowPath getFlowPathByFlowEntry(IFlowEntry flowEntry) {
 		FramedGraph<TitanGraph> fg = conn.getFramedGraph();
 		GremlinPipeline<Vertex, IFlowPath> pipe = new GremlinPipeline<Vertex, IFlowPath>();
 		pipe.start(flowEntry.asVertex());
@@ -150,7 +162,7 @@
 	}
 
 	@Override
-    public Iterable<IFlowPath> getAllFlowPaths(GraphDBConnection conn) {
+    public Iterable<IFlowPath> getAllFlowPaths() {
 		FramedGraph<TitanGraph> fg = conn.getFramedGraph();
 		Iterable<IFlowPath> flowPaths = fg.getVertices("type", "flow", IFlowPath.class);
 		
@@ -165,8 +177,7 @@
 	}
 
 	@Override
-	public IFlowEntry searchFlowEntry(GraphDBConnection conn,
-					  FlowEntryId flowEntryId) {
+	public IFlowEntry searchFlowEntry(FlowEntryId flowEntryId) {
 		FramedGraph<TitanGraph> fg = conn.getFramedGraph();
 		
 		return fg.getVertices("flow_entry_id", flowEntryId.toString()).iterator().hasNext() ? 
@@ -175,35 +186,35 @@
 	}
 
 	@Override
-	public IFlowEntry newFlowEntry(GraphDBConnection conn) {
+	public IFlowEntry newFlowEntry() {
 		FramedGraph<TitanGraph> fg = conn.getFramedGraph();	
 		IFlowEntry flowEntry = fg.addVertex(null, IFlowEntry.class);
+		if (flowEntry != null) flowEntry.setType("flow_entry");
 		return flowEntry;
 	}
 
 	@Override
-	public void removeFlowEntry(GraphDBConnection conn,
-				    IFlowEntry flowEntry) {
+	public void removeFlowEntry(IFlowEntry flowEntry) {
 		FramedGraph<TitanGraph> fg = conn.getFramedGraph();
 		fg.removeVertex(flowEntry.asVertex());
 	}
 
 	@Override
-        public Iterable<IFlowEntry> getAllFlowEntries(GraphDBConnection conn) {
+        public Iterable<IFlowEntry> getAllFlowEntries() {
 		FramedGraph<TitanGraph> fg = conn.getFramedGraph();
 		
 		return fg.getVertices("type", "flow_entry", IFlowEntry.class);
 	}
 	
 	@Override
-	public Iterable<IFlowEntry> getAllSwitchNotUpdatedFlowEntries(GraphDBConnection conn) {
+	public Iterable<IFlowEntry> getAllSwitchNotUpdatedFlowEntries() {
 		FramedGraph<TitanGraph> fg = conn.getFramedGraph();
 		//TODO: Should use an enum for flow_switch_state
 		return fg.getVertices("switch_state", "FE_SWITCH_NOT_UPDATED", IFlowEntry.class);
 	}
 
 	@Override
-	public Iterable<ISwitchObject> getActiveSwitches(GraphDBConnection conn) {
+	public Iterable<ISwitchObject> getActiveSwitches() {
 		FramedGraph<TitanGraph> fg = conn.getFramedGraph();
 		Iterable<ISwitchObject> switches =  fg.getVertices("type","switch",ISwitchObject.class);
 		List<ISwitchObject> activeSwitches = new ArrayList<ISwitchObject>();
@@ -217,14 +228,14 @@
 	}
 
 	@Override
-	public Iterable<ISwitchObject> getAllSwitches(GraphDBConnection conn) {
+	public Iterable<ISwitchObject> getAllSwitches() {
 		FramedGraph<TitanGraph> fg = conn.getFramedGraph();
 		Iterable<ISwitchObject> switches =  fg.getVertices("type","switch",ISwitchObject.class);
 		return switches;
 	}
 
 	@Override
-	public Iterable<ISwitchObject> getInactiveSwitches(GraphDBConnection conn) {
+	public Iterable<ISwitchObject> getInactiveSwitches() {
 		FramedGraph<TitanGraph> fg = conn.getFramedGraph();
 		Iterable<ISwitchObject> switches =  fg.getVertices("type","switch",ISwitchObject.class);
 		List<ISwitchObject> inactiveSwitches = new ArrayList<ISwitchObject>();
@@ -238,9 +249,9 @@
 	}
 
 	@Override
-	public ISwitchObject searchActiveSwitch(GraphDBConnection conn, String dpid) {
+	public ISwitchObject searchActiveSwitch(String dpid) {
 
-        ISwitchObject sw = searchSwitch(conn, dpid);
+        ISwitchObject sw = searchSwitch(dpid);
         if ((sw != null) &&
             sw.getState().equals(SwitchState.ACTIVE.toString())) {
             return sw;
diff --git a/src/main/java/net/onrc/onos/util/IDBConnection.java b/src/main/java/net/onrc/onos/util/IDBConnection.java
new file mode 100644
index 0000000..e599a5e
--- /dev/null
+++ b/src/main/java/net/onrc/onos/util/IDBConnection.java
@@ -0,0 +1,19 @@
+package net.onrc.onos.util;
+
+import net.onrc.onos.util.GraphDBConnection.GenerateEvent;
+import net.onrc.onos.util.GraphDBConnection.Transaction;
+import net.onrc.onos.util.GraphDBConnection.TransactionHandle;
+
+import com.thinkaurelius.titan.core.TitanGraph;
+import com.tinkerpop.frames.FramedGraph;
+
+public interface IDBConnection {
+	public FramedGraph<TitanGraph> getFramedGraph();
+	public void addEventListener(final LocalGraphChangedListener listener);
+	public Boolean isValid();
+	public void startTx();
+	public void endTx(Transaction tx);
+	public void endTx(TransactionHandle tr, Transaction tx);
+	public void endTx(Transaction tx, GenerateEvent fire);
+	public void close();
+}
diff --git a/src/main/java/net/onrc/onos/util/IDBOperation.java b/src/main/java/net/onrc/onos/util/IDBOperation.java
new file mode 100644
index 0000000..6a0d52d
--- /dev/null
+++ b/src/main/java/net/onrc/onos/util/IDBOperation.java
@@ -0,0 +1,40 @@
+package net.onrc.onos.util;
+
+import net.floodlightcontroller.core.INetMapTopologyObjects.IDeviceObject;
+import net.floodlightcontroller.core.INetMapTopologyObjects.IFlowEntry;
+import net.floodlightcontroller.core.INetMapTopologyObjects.IFlowPath;
+import net.floodlightcontroller.core.INetMapTopologyObjects.IPortObject;
+import net.floodlightcontroller.core.INetMapTopologyObjects.ISwitchObject;
+import net.floodlightcontroller.util.FlowEntryId;
+import net.floodlightcontroller.util.FlowId;
+
+public interface IDBOperation {	
+	public ISwitchObject newSwitch(String dpid);
+	public ISwitchObject searchSwitch(String dpid);
+	public ISwitchObject searchActiveSwitch(String dpid);
+	public Iterable<ISwitchObject> getActiveSwitches();
+	public Iterable<ISwitchObject> getAllSwitches();
+	public Iterable<ISwitchObject> getInactiveSwitches();
+	public Iterable<IFlowEntry> getAllSwitchNotUpdatedFlowEntries();
+	public void removeSwitch(ISwitchObject sw);
+	
+	public IPortObject newPort(Short portNumber);
+	public IPortObject searchPort(String dpid, short number);
+	public void removePort(IPortObject port);
+	
+	public IDeviceObject newDevice();
+	public IDeviceObject searchDevice(String macAddr);
+	public Iterable<IDeviceObject> getDevices();
+	public void removeDevice(IDeviceObject dev);
+
+	public IFlowPath newFlowPath();
+	public IFlowPath searchFlowPath(FlowId flowId);
+	public IFlowPath getFlowPathByFlowEntry(IFlowEntry flowEntry);
+	public Iterable<IFlowPath> getAllFlowPaths();
+	public void removeFlowPath(IFlowPath flowPath);
+
+	public IFlowEntry newFlowEntry();
+	public IFlowEntry searchFlowEntry(FlowEntryId flowEntryId);
+	public Iterable<IFlowEntry> getAllFlowEntries();
+	public void removeFlowEntry(IFlowEntry flowEntry);
+}
diff --git a/src/main/java/net/onrc/onos/util/IDBUtils.java b/src/main/java/net/onrc/onos/util/IDBUtils.java
deleted file mode 100644
index a16e136..0000000
--- a/src/main/java/net/onrc/onos/util/IDBUtils.java
+++ /dev/null
@@ -1,41 +0,0 @@
-package net.onrc.onos.util;
-
-import net.onrc.onos.ofcontroller.core.INetMapTopologyObjects.IDeviceObject;
-import net.onrc.onos.ofcontroller.core.INetMapTopologyObjects.IFlowEntry;
-import net.onrc.onos.ofcontroller.core.INetMapTopologyObjects.IFlowPath;
-import net.onrc.onos.ofcontroller.core.INetMapTopologyObjects.IPortObject;
-import net.onrc.onos.ofcontroller.core.INetMapTopologyObjects.ISwitchObject;
-import net.onrc.onos.ofcontroller.util.FlowEntryId;
-import net.onrc.onos.ofcontroller.util.FlowId;
-
-public interface IDBUtils {	
-	public ISwitchObject searchSwitch(GraphDBConnection conn, String dpid);
-	public ISwitchObject searchActiveSwitch(GraphDBConnection conn, String dpid);
-	public Iterable<ISwitchObject> getActiveSwitches(GraphDBConnection conn);
-	public Iterable<ISwitchObject> getAllSwitches(GraphDBConnection conn);
-	public Iterable<ISwitchObject> getInactiveSwitches(GraphDBConnection conn);
-	
-
-	public IDeviceObject searchDevice(GraphDBConnection conn, String macAddr);
-	public IDeviceObject newDevice(GraphDBConnection conn);
-	public void removeDevice(GraphDBConnection conn, IDeviceObject dev);
-	public IPortObject searchPort(GraphDBConnection conn, String dpid, short number);
-	public Iterable<IDeviceObject> getDevices(GraphDBConnection conn);
-	public IFlowPath searchFlowPath(GraphDBConnection conn, FlowId flowId);
-	public IFlowPath newFlowPath(GraphDBConnection conn);
-	public void removeFlowPath(GraphDBConnection conn, IFlowPath flowPath);
-        public IFlowPath getFlowPathByFlowEntry(GraphDBConnection conn,
-						IFlowEntry flowEntry);
-	public Iterable<IFlowPath> getAllFlowPaths(GraphDBConnection conn);
-	public IFlowEntry searchFlowEntry(GraphDBConnection conn,
-					  FlowEntryId flowEntryId);
-	public IFlowEntry newFlowEntry(GraphDBConnection conn);
-	public void removeFlowEntry(GraphDBConnection conn,
-				    IFlowEntry flowEntry);
-	public Iterable<IFlowEntry> getAllFlowEntries(GraphDBConnection conn);
-	public IPortObject newPort(GraphDBConnection conn);
-	ISwitchObject newSwitch(GraphDBConnection conn);
-	void removePort(GraphDBConnection conn, IPortObject port);
-	void removeSwitch(GraphDBConnection conn, ISwitchObject sw);
-	Iterable<IFlowEntry> getAllSwitchNotUpdatedFlowEntries(GraphDBConnection conn);
-}
diff --git a/src/test/java/net/onrc/onos/util/GraphDBOperationTest.java b/src/test/java/net/onrc/onos/util/GraphDBOperationTest.java
new file mode 100644
index 0000000..01f244c
--- /dev/null
+++ b/src/test/java/net/onrc/onos/util/GraphDBOperationTest.java
@@ -0,0 +1,298 @@
+/**
+ * 
+ */
+package net.onrc.onos.util;
+
+import static org.junit.Assert.*;
+
+import net.floodlightcontroller.core.INetMapTopologyObjects.ISwitchObject;
+import net.floodlightcontroller.core.ISwitchStorage.SwitchState;
+import net.floodlightcontroller.core.internal.TestDatabaseManager;
+import net.onrc.onos.util.GraphDBConnection.Transaction;
+
+import org.easymock.EasyMock;
+import org.junit.After;
+import org.junit.AfterClass;
+import org.junit.Before;
+import org.junit.BeforeClass;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.powermock.api.easymock.PowerMock;
+import org.powermock.core.classloader.annotations.PrepareForTest;
+import org.powermock.modules.junit4.PowerMockRunner;
+
+import com.thinkaurelius.titan.core.TitanFactory;
+import com.thinkaurelius.titan.core.TitanGraph;
+
+/**
+ * @author Toshio Koide
+ *
+ */
+@RunWith(PowerMockRunner.class)
+@PrepareForTest({TitanFactory.class})
+public class GraphDBOperationTest {
+	private static TitanGraph titanGraph;
+	private static GraphDBConnection conn;
+	private static GraphDBOperation op;
+
+	/**
+	 * @throws java.lang.Exception
+	 */
+	@BeforeClass
+	public static void setUpBeforeClass() throws Exception {
+	}
+
+	/**
+	 * @throws java.lang.Exception
+	 */
+	@AfterClass
+	public static void tearDownAfterClass() throws Exception {
+	}
+
+	/**
+	 * @throws java.lang.Exception
+	 */
+	@Before
+	public void setUp() throws Exception {
+		TestDatabaseManager.deleteTestDatabase();
+		titanGraph = TestDatabaseManager.getTestDatabase();
+//		TestDatabaseManager.populateTestData(titanGraph);
+		
+		// replace return value of TitanFactory.open() to dummy DB created above
+		PowerMock.mockStatic(TitanFactory.class);
+		EasyMock.expect(TitanFactory.open((String)EasyMock.anyObject())).andReturn(titanGraph);
+		PowerMock.replay(TitanFactory.class);
+		
+		conn = GraphDBConnection.getInstance("/dummy/to/conf");
+		op = new GraphDBOperation(conn);
+	}
+
+	/**
+	 * @throws java.lang.Exception
+	 */
+	@After
+	public void tearDown() throws Exception {
+		conn.close();
+		titanGraph.shutdown();
+	}
+
+	/**
+	 * Test method for {@link net.onrc.onos.util.GraphDBOperation#newSwitch(net.onrc.onos.util.GraphDBConnection)}.
+	 */
+	@Test
+	public final void testNewSwitch() {
+		Iterable<ISwitchObject> switches;
+
+		switches = op.getAllSwitches();
+		assertFalse(switches.iterator().hasNext());
+
+		ISwitchObject sw = op.newSwitch("123");
+		sw.setState(SwitchState.ACTIVE.toString());
+		conn.endTx(Transaction.COMMIT);
+
+		switches = op.getAllSwitches();
+		assertTrue(switches.iterator().hasNext());
+		
+		ISwitchObject obtained_sw = switches.iterator().next();
+		String obtained_dpid = obtained_sw.getDPID(); 
+		assertEquals("123", obtained_dpid);
+	}
+
+	/**
+	 * Test method for {@link net.onrc.onos.util.GraphDBOperation#removeSwitch(net.onrc.onos.util.GraphDBConnection, net.floodlightcontroller.core.INetMapTopologyObjects.ISwitchObject)}.
+	 */
+	@Test
+	public final void testRemoveSwitch() {
+		Iterable<ISwitchObject> switches;
+
+		// make sure there is no switch
+		switches = op.getAllSwitches();
+		assertFalse(switches.iterator().hasNext());
+		
+		ISwitchObject sw = op.newSwitch("123");
+		sw.setState(SwitchState.ACTIVE.toString());
+		conn.endTx(Transaction.COMMIT);
+		
+		sw = op.searchSwitch("123");
+		op.removeSwitch(sw);
+
+		assertNull(op.searchSwitch("123"));
+	}
+
+	/**
+	 * Test method for {@link net.onrc.onos.util.GraphDBOperation#searchSwitch(net.onrc.onos.util.GraphDBConnection, java.lang.String)}.
+	 */
+	@Test
+	public final void testSearchSwitch() {
+		fail("Not yet implemented");
+	}
+
+	/**
+	 * Test method for {@link net.onrc.onos.util.GraphDBOperation#searchDevice(net.onrc.onos.util.GraphDBConnection, java.lang.String)}.
+	 */
+	@Test
+	public final void testSearchDevice() {
+		fail("Not yet implemented");
+	}
+
+	/**
+	 * Test method for {@link net.onrc.onos.util.GraphDBOperation#searchPort(net.onrc.onos.util.GraphDBConnection, java.lang.String, short)}.
+	 */
+	@Test
+	public final void testSearchPort() {
+		fail("Not yet implemented");
+	}
+
+	/**
+	 * Test method for {@link net.onrc.onos.util.GraphDBOperation#newPort(net.onrc.onos.util.GraphDBConnection)}.
+	 */
+	@Test
+	public final void testNewPort() {
+		fail("Not yet implemented");
+	}
+
+	/**
+	 * Test method for {@link net.onrc.onos.util.GraphDBOperation#newDevice(net.onrc.onos.util.GraphDBConnection)}.
+	 */
+	@Test
+	public final void testNewDevice() {
+		fail("Not yet implemented");
+	}
+
+	/**
+	 * Test method for {@link net.onrc.onos.util.GraphDBOperation#removePort(net.onrc.onos.util.GraphDBConnection, net.floodlightcontroller.core.INetMapTopologyObjects.IPortObject)}.
+	 */
+	@Test
+	public final void testRemovePort() {
+		fail("Not yet implemented");
+	}
+
+	/**
+	 * Test method for {@link net.onrc.onos.util.GraphDBOperation#removeDevice(net.onrc.onos.util.GraphDBConnection, net.floodlightcontroller.core.INetMapTopologyObjects.IDeviceObject)}.
+	 */
+	@Test
+	public final void testRemoveDevice() {
+		fail("Not yet implemented");
+	}
+
+	/**
+	 * Test method for {@link net.onrc.onos.util.GraphDBOperation#getDevices(net.onrc.onos.util.GraphDBConnection)}.
+	 */
+	@Test
+	public final void testGetDevices() {
+		fail("Not yet implemented");
+	}
+
+	/**
+	 * Test method for {@link net.onrc.onos.util.GraphDBOperation#searchFlowPath(net.onrc.onos.util.GraphDBConnection, net.floodlightcontroller.util.FlowId)}.
+	 */
+	@Test
+	public final void testSearchFlowPath() {
+		fail("Not yet implemented");
+	}
+
+	/**
+	 * Test method for {@link net.onrc.onos.util.GraphDBOperation#newFlowPath(net.onrc.onos.util.GraphDBConnection)}.
+	 */
+	@Test
+	public final void testNewFlowPath() {
+		fail("Not yet implemented");
+	}
+
+	/**
+	 * Test method for {@link net.onrc.onos.util.GraphDBOperation#removeFlowPath(net.onrc.onos.util.GraphDBConnection, net.floodlightcontroller.core.INetMapTopologyObjects.IFlowPath)}.
+	 */
+	@Test
+	public final void testRemoveFlowPath() {
+		fail("Not yet implemented");
+	}
+
+	/**
+	 * Test method for {@link net.onrc.onos.util.GraphDBOperation#getFlowPathByFlowEntry(net.onrc.onos.util.GraphDBConnection, net.floodlightcontroller.core.INetMapTopologyObjects.IFlowEntry)}.
+	 */
+	@Test
+	public final void testGetFlowPathByFlowEntry() {
+		fail("Not yet implemented");
+	}
+
+	/**
+	 * Test method for {@link net.onrc.onos.util.GraphDBOperation#getAllFlowPaths(net.onrc.onos.util.GraphDBConnection)}.
+	 */
+	@Test
+	public final void testGetAllFlowPaths() {
+		fail("Not yet implemented");
+	}
+
+	/**
+	 * Test method for {@link net.onrc.onos.util.GraphDBOperation#searchFlowEntry(net.onrc.onos.util.GraphDBConnection, net.floodlightcontroller.util.FlowEntryId)}.
+	 */
+	@Test
+	public final void testSearchFlowEntry() {
+		fail("Not yet implemented");
+	}
+
+	/**
+	 * Test method for {@link net.onrc.onos.util.GraphDBOperation#newFlowEntry(net.onrc.onos.util.GraphDBConnection)}.
+	 */
+	@Test
+	public final void testNewFlowEntry() {
+		fail("Not yet implemented");
+	}
+
+	/**
+	 * Test method for {@link net.onrc.onos.util.GraphDBOperation#removeFlowEntry(net.onrc.onos.util.GraphDBConnection, net.floodlightcontroller.core.INetMapTopologyObjects.IFlowEntry)}.
+	 */
+	@Test
+	public final void testRemoveFlowEntry() {
+		fail("Not yet implemented");
+	}
+
+	/**
+	 * Test method for {@link net.onrc.onos.util.GraphDBOperation#getAllFlowEntries(net.onrc.onos.util.GraphDBConnection)}.
+	 */
+	@Test
+	public final void testGetAllFlowEntries() {
+		fail("Not yet implemented");
+	}
+
+	/**
+	 * Test method for {@link net.onrc.onos.util.GraphDBOperation#getAllSwitchNotUpdatedFlowEntries(net.onrc.onos.util.GraphDBConnection)}.
+	 */
+	@Test
+	public final void testGetAllSwitchNotUpdatedFlowEntries() {
+		fail("Not yet implemented");
+	}
+
+	/**
+	 * Test method for {@link net.onrc.onos.util.GraphDBOperation#getActiveSwitches(net.onrc.onos.util.GraphDBConnection)}.
+	 */
+	@Test
+	public final void testGetActiveSwitches() {
+		fail("Not yet implemented");
+	}
+
+	/**
+	 * Test method for {@link net.onrc.onos.util.GraphDBOperation#getAllSwitches(net.onrc.onos.util.GraphDBConnection)}.
+	 */
+	@Test
+	public final void testGetAllSwitches() {
+		fail("Not yet implemented");
+	}
+
+	/**
+	 * Test method for {@link net.onrc.onos.util.GraphDBOperation#getInactiveSwitches(net.onrc.onos.util.GraphDBConnection)}.
+	 */
+	@Test
+	public final void testGetInactiveSwitches() {
+		fail("Not yet implemented");
+	}
+
+	/**
+	 * Test method for {@link net.onrc.onos.util.GraphDBOperation#searchActiveSwitch(net.onrc.onos.util.GraphDBConnection, java.lang.String)}.
+	 */
+	@Test
+	public final void testSearchActiveSwitch() {
+		fail("Not yet implemented");
+	}
+
+}