ONOS-1443: Group bucket statistics support and group CLI formatting

Change-Id: Iaa6d8ae1f9222eb9c29d14bf1615a7449e50c4d3
diff --git a/cli/src/main/java/org/onosproject/cli/Comparators.java b/cli/src/main/java/org/onosproject/cli/Comparators.java
index 6efb139..cbb22a5 100644
--- a/cli/src/main/java/org/onosproject/cli/Comparators.java
+++ b/cli/src/main/java/org/onosproject/cli/Comparators.java
@@ -25,6 +25,7 @@
 import org.onosproject.net.ElementId;
 import org.onosproject.net.Port;
 import org.onosproject.net.flow.FlowRule;
+import org.onosproject.net.group.Group;
 import org.onosproject.net.host.PortAddresses;
 import org.onosproject.net.topology.TopologyCluster;
 
@@ -72,6 +73,13 @@
         }
     };
 
+    public static final Comparator<Group> GROUP_COMPARATOR = new Comparator<Group>() {
+        @Override
+        public int compare(Group g1, Group g2) {
+            return Long.valueOf(g1.id().id()).compareTo(Long.valueOf(g2.id().id()));
+        }
+    };
+
     public static final Comparator<Port> PORT_COMPARATOR = new Comparator<Port>() {
         @Override
         public int compare(Port p1, Port p2) {