Replace comparator definitions with their Lambda equivalents.

Change-Id: Ib626e086f78aa950be20cb84e56a3769517bac0a
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 fc81682..95a9874 100644
--- a/core/common/src/main/java/org/onosproject/utils/Comparators.java
+++ b/core/common/src/main/java/org/onosproject/utils/Comparators.java
@@ -23,13 +23,13 @@
 import org.onosproject.incubator.net.virtual.VirtualDevice;
 import org.onosproject.incubator.net.virtual.VirtualNetwork;
 import org.onosproject.incubator.net.virtual.VirtualPort;
-import org.onosproject.net.key.DeviceKey;
 import org.onosproject.net.ConnectPoint;
 import org.onosproject.net.Element;
 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.key.DeviceKey;
 import org.onosproject.net.region.Region;
 import org.onosproject.net.statistic.TypedFlowEntryWithLoad;
 import org.onosproject.net.topology.TopologyCluster;
@@ -46,146 +46,83 @@
     private Comparators() {
     }
 
-    public static final Comparator<ApplicationId> APP_ID_COMPARATOR = new Comparator<ApplicationId>() {
-        @Override
-        public int compare(ApplicationId id1, ApplicationId id2) {
-            return id1.id() - id2.id();
-        }
-    };
+    public static final Comparator<ApplicationId> APP_ID_COMPARATOR =
+            (id1, id2) -> id1.id() - id2.id();
 
-    public static final Comparator<Application> APP_COMPARATOR = new Comparator<Application>() {
-        @Override
-        public int compare(Application app1, Application app2) {
-            return app1.id().id() - app2.id().id();
-        }
-    };
+    public static final Comparator<Application> APP_COMPARATOR =
+            (app1, app2) -> app1.id().id() - app2.id().id();
 
-    public static final Comparator<ElementId> ELEMENT_ID_COMPARATOR = new Comparator<ElementId>() {
-        @Override
-        public int compare(ElementId id1, ElementId id2) {
-            return id1.toString().compareTo(id2.toString());
-        }
-    };
+    public static final Comparator<ElementId> ELEMENT_ID_COMPARATOR =
+            (id1, id2) -> id1.toString().compareTo(id2.toString());
 
-    public static final Comparator<Element> ELEMENT_COMPARATOR = new Comparator<Element>() {
-        @Override
-        public int compare(Element e1, Element e2) {
-            return e1.id().toString().compareTo(e2.id().toString());
-        }
-    };
+    public static final Comparator<Element> ELEMENT_COMPARATOR =
+            (e1, e2) -> e1.id().toString().compareTo(e2.id().toString());
 
-    public static final Comparator<FlowRule> FLOW_RULE_COMPARATOR = new Comparator<FlowRule>() {
-        @Override
-        public int compare(FlowRule f1, FlowRule f2) {
-            // Compare table IDs in ascending order
-            int tableCompare = f1.tableId() - f2.tableId();
-            if (tableCompare != 0) {
-                return tableCompare;
-            }
-            // Compare priorities in descending order
-            int priorityCompare = f2.priority() - f1.priority();
-            return (priorityCompare == 0)
-                    ? Long.valueOf(f1.id().value()).compareTo(f2.id().value())
-                    : priorityCompare;
-        }
-    };
-
-    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) {
-            long delta = p1.number().toLong() - p2.number().toLong();
-            return delta == 0 ? 0 : (delta < 0 ? -1 : +1);
-        }
-    };
-
-    public static final Comparator<TopologyCluster> CLUSTER_COMPARATOR = new Comparator<TopologyCluster>() {
-        @Override
-        public int compare(TopologyCluster c1, TopologyCluster c2) {
-            return c1.id().index() - c2.id().index();
-        }
-    };
-
-    public static final Comparator<ControllerNode> NODE_COMPARATOR = new Comparator<ControllerNode>() {
-        @Override
-        public int compare(ControllerNode ci1, ControllerNode ci2) {
-            return ci1.id().toString().compareTo(ci2.id().toString());
-        }
-    };
-
-    public static final Comparator<ConnectPoint> CONNECT_POINT_COMPARATOR = new Comparator<ConnectPoint>() {
-        @Override
-        public int compare(ConnectPoint o1, ConnectPoint o2) {
-            int compareId = ELEMENT_ID_COMPARATOR.compare(o1.elementId(), o2.elementId());
-            return (compareId != 0) ?
-                    compareId :
-                    Long.signum(o1.port().toLong() - o2.port().toLong());
-        }
-    };
-
-    public static final Comparator<Interface> INTERFACES_COMPARATOR = (intf1, intf2) ->
-            CONNECT_POINT_COMPARATOR.compare(intf1.connectPoint(), intf2.connectPoint());
-
-    public static final Comparator<TypedFlowEntryWithLoad> TYPEFLOWENTRY_WITHLOAD_COMPARATOR =
-            new Comparator<TypedFlowEntryWithLoad>() {
-                @Override
-                public int compare(TypedFlowEntryWithLoad fe1, TypedFlowEntryWithLoad fe2) {
-                    long delta = fe1.load().rate() - fe2.load().rate();
-                    return delta == 0 ? 0 : (delta > 0 ? -1 : +1);
+    public static final Comparator<FlowRule> FLOW_RULE_COMPARATOR =
+            (f1, f2) -> {
+                // Compare table IDs in ascending order
+                int tableCompare = f1.tableId() - f2.tableId();
+                if (tableCompare != 0) {
+                    return tableCompare;
                 }
+                // Compare priorities in descending order
+                int priorityCompare = f2.priority() - f1.priority();
+                return (priorityCompare == 0)
+                        ? Long.valueOf(f1.id().value()).compareTo(f2.id().value())
+                        : priorityCompare;
             };
 
-    public static final Comparator<DeviceKey> DEVICE_KEY_COMPARATOR = new Comparator<DeviceKey>() {
-        @Override
-        public int compare(DeviceKey deviceKey1, DeviceKey deviceKey2) {
-            return deviceKey1.deviceKeyId().id().compareTo(deviceKey2.deviceKeyId().id());
-        }
-    };
+    public static final Comparator<Group> GROUP_COMPARATOR =
+            (g1, g2) -> Long.valueOf(g1.id().id()).compareTo((long) g2.id().id());
 
-    public static final Comparator<Region> REGION_COMPARATOR = new Comparator<Region>() {
-        @Override
-        public int compare(Region region1, Region region2) {
-            return region1.id().toString().compareTo(region2.id().toString());
-        }
-    };
+    public static final Comparator<Port> PORT_COMPARATOR =
+            (p1, p2) -> {
+                long delta = p1.number().toLong() - p2.number().toLong();
+                return delta == 0 ? 0 : (delta < 0 ? -1 : +1);
+            };
 
-    public static final Comparator<UiTopoLayout> LAYOUT_COMPARATOR = new Comparator<UiTopoLayout>() {
-        @Override
-        public int compare(UiTopoLayout l1, UiTopoLayout l2) {
-            return l1.id().toString().compareTo(l2.id().toString());
-        }
-    };
-    public static final Comparator<TenantId> TENANT_ID_COMPARATOR = new Comparator<TenantId>() {
-        @Override
-        public int compare(TenantId tenant1, TenantId tenant2) {
-            return tenant1.id().compareTo(tenant2.id());
-        }
-    };
+    public static final Comparator<TopologyCluster> CLUSTER_COMPARATOR =
+            (c1, c2) -> c1.id().index() - c2.id().index();
 
-    public static final Comparator<VirtualNetwork> VIRTUAL_NETWORK_COMPARATOR = new Comparator<VirtualNetwork>() {
-        @Override
-        public int compare(VirtualNetwork virtualNetwork1, VirtualNetwork virtualNetwork2) {
-            return virtualNetwork1.tenantId().toString().compareTo(virtualNetwork2.tenantId().toString());
-        }
-    };
+    public static final Comparator<ControllerNode> NODE_COMPARATOR =
+            (ci1, ci2) -> ci1.id().toString().compareTo(ci2.id().toString());
 
-    public static final Comparator<VirtualDevice> VIRTUAL_DEVICE_COMPARATOR = new Comparator<VirtualDevice>() {
-        @Override
-        public int compare(VirtualDevice virtualDevice1, VirtualDevice virtualDevice2) {
-            return virtualDevice1.id().toString().compareTo(virtualDevice2.id().toString());
-        }
-    };
+    public static final Comparator<ConnectPoint> CONNECT_POINT_COMPARATOR =
+            (o1, o2) -> {
+                int compareId = ELEMENT_ID_COMPARATOR.compare(o1.elementId(), o2.elementId());
+                return (compareId != 0) ?
+                        compareId :
+                        Long.signum(o1.port().toLong() - o2.port().toLong());
+            };
 
-    public static final Comparator<VirtualPort> VIRTUAL_PORT_COMPARATOR = new Comparator<VirtualPort>() {
-        @Override
-        public int compare(VirtualPort virtualPort1, VirtualPort virtualPort2) {
-            return virtualPort1.number().toString().compareTo(virtualPort2.number().toString());
-        }
-    };
+    public static final Comparator<Interface> INTERFACES_COMPARATOR =
+            (intf1, intf2) ->
+                    CONNECT_POINT_COMPARATOR.compare(intf1.connectPoint(), intf2.connectPoint());
+
+    public static final Comparator<TypedFlowEntryWithLoad> TYPEFLOWENTRY_WITHLOAD_COMPARATOR =
+            (fe1, fe2) -> {
+                long delta = fe1.load().rate() - fe2.load().rate();
+                return delta == 0 ? 0 : (delta > 0 ? -1 : +1);
+            };
+
+    public static final Comparator<DeviceKey> DEVICE_KEY_COMPARATOR =
+            (dk1, dk2) -> dk1.deviceKeyId().id().compareTo(dk2.deviceKeyId().id());
+
+    public static final Comparator<Region> REGION_COMPARATOR =
+            (r1, r2) -> r1.id().toString().compareTo(r2.id().toString());
+
+    public static final Comparator<UiTopoLayout> LAYOUT_COMPARATOR =
+            (l1, l2) -> l1.id().toString().compareTo(l2.id().toString());
+
+    public static final Comparator<TenantId> TENANT_ID_COMPARATOR =
+            (t1, t2) -> t1.id().compareTo(t2.id());
+
+    public static final Comparator<VirtualNetwork> VIRTUAL_NETWORK_COMPARATOR =
+            (v1, v2) -> v1.tenantId().toString().compareTo(v2.tenantId().toString());
+
+    public static final Comparator<VirtualDevice> VIRTUAL_DEVICE_COMPARATOR =
+            (v1, v2) -> v1.id().toString().compareTo(v2.id().toString());
+
+    public static final Comparator<VirtualPort> VIRTUAL_PORT_COMPARATOR =
+            (v1, v2) -> v1.number().toString().compareTo(v2.number().toString());
 }