[ONOS-7144] Membership CLI Command

Change-Id: I7f36e288f3ff2ebb5a1df74123a8e1adb22cb769
diff --git a/core/common/src/main/java/org/onosproject/utils/Comparators.java b/core/common/src/main/java/org/onosproject/utils/Comparators.java
index c03c99b..b509012 100644
--- a/core/common/src/main/java/org/onosproject/utils/Comparators.java
+++ b/core/common/src/main/java/org/onosproject/utils/Comparators.java
@@ -16,6 +16,7 @@
 package org.onosproject.utils;
 
 import org.onosproject.cluster.ControllerNode;
+import org.onosproject.cluster.Member;
 import org.onosproject.core.Application;
 import org.onosproject.core.ApplicationId;
 import org.onosproject.net.intf.Interface;
@@ -93,6 +94,9 @@
     public static final Comparator<ControllerNode> NODE_COMPARATOR =
             (ci1, ci2) -> ci1.id().toString().compareTo(ci2.id().toString());
 
+    public static final Comparator<Member> MEMBERSHIP_COMPARATOR =
+            (ci1, ci2) -> ci1.nodeId().toString().compareTo(ci2.nodeId().toString());
+
     public static final Comparator<ConnectPoint> CONNECT_POINT_COMPARATOR =
             (o1, o2) -> {
                 int compareId = ELEMENT_ID_COMPARATOR.compare(o1.elementId(), o2.elementId());