Fixed equals methods for better efficiency.
Cleaned up ClusterService API.
diff --git a/core/api/src/main/java/org/onlab/onos/net/topology/DefaultTopologyCluster.java b/core/api/src/main/java/org/onlab/onos/net/topology/DefaultTopologyCluster.java
index f33dcf7..b6cc9bd 100644
--- a/core/api/src/main/java/org/onlab/onos/net/topology/DefaultTopologyCluster.java
+++ b/core/api/src/main/java/org/onlab/onos/net/topology/DefaultTopologyCluster.java
@@ -59,6 +59,9 @@
 
     @Override
     public boolean equals(Object obj) {
+        if (this == obj) {
+            return true;
+        }
         if (obj instanceof DefaultTopologyCluster) {
             final DefaultTopologyCluster other = (DefaultTopologyCluster) obj;
             return Objects.equals(this.id, other.id) &&