Fixed equals methods for better efficiency.
Cleaned up ClusterService API.
diff --git a/core/api/src/main/java/org/onlab/onos/net/topology/DefaultTopologyVertex.java b/core/api/src/main/java/org/onlab/onos/net/topology/DefaultTopologyVertex.java
index 7bc231e..4337f58 100644
--- a/core/api/src/main/java/org/onlab/onos/net/topology/DefaultTopologyVertex.java
+++ b/core/api/src/main/java/org/onlab/onos/net/topology/DefaultTopologyVertex.java
@@ -32,6 +32,9 @@
 
     @Override
     public boolean equals(Object obj) {
+        if (this == obj) {
+            return true;
+        }
         if (obj instanceof DefaultTopologyVertex) {
             final DefaultTopologyVertex other = (DefaultTopologyVertex) obj;
             return Objects.equals(this.deviceId, other.deviceId);