add another GraphDBOperation constructor which creates an instance directry from GraphDBConnection configuration path.
diff --git a/src/main/java/net/onrc/onos/ofcontroller/core/internal/TopoSwitchServiceImpl.java b/src/main/java/net/onrc/onos/ofcontroller/core/internal/TopoSwitchServiceImpl.java
index e279422..c1659fb 100644
--- a/src/main/java/net/onrc/onos/ofcontroller/core/internal/TopoSwitchServiceImpl.java
+++ b/src/main/java/net/onrc/onos/ofcontroller/core/internal/TopoSwitchServiceImpl.java
@@ -3,7 +3,6 @@
 import net.onrc.onos.ofcontroller.core.INetMapTopologyObjects.IPortObject;
 import net.onrc.onos.ofcontroller.core.INetMapTopologyObjects.ISwitchObject;
 import net.onrc.onos.ofcontroller.core.INetMapTopologyService.ITopoSwitchService;
-import net.onrc.onos.util.GraphDBConnection;
 import net.onrc.onos.util.GraphDBOperation;
 
 import org.slf4j.Logger;
@@ -15,7 +14,7 @@
 	protected static Logger log = LoggerFactory.getLogger(TopoSwitchServiceImpl.class);
 
 	public TopoSwitchServiceImpl(String conf) {
-		op = new GraphDBOperation(GraphDBConnection.getInstance(conf));
+		op = new GraphDBOperation(conf);
 	}
 
 	public TopoSwitchServiceImpl() {