Implemented a globally unique next id generator in FlowObjectStore

Change-Id: Ib98b2996e1ebcca56ad816ea94f25d838c5f4d44
diff --git a/core/net/src/main/java/org/onosproject/net/flowobjective/impl/FlowObjectiveManager.java b/core/net/src/main/java/org/onosproject/net/flowobjective/impl/FlowObjectiveManager.java
index 17b0aa7..6b84bfa 100644
--- a/core/net/src/main/java/org/onosproject/net/flowobjective/impl/FlowObjectiveManager.java
+++ b/core/net/src/main/java/org/onosproject/net/flowobjective/impl/FlowObjectiveManager.java
@@ -170,6 +170,11 @@
         }
     }
 
+    @Override
+    public int allocateNextId() {
+        return flowObjectiveStore.allocateNextId();
+    }
+
     private boolean queueObjective(DeviceId deviceId, ForwardingObjective fwd) {
         if (fwd.nextId() != null &&
                 flowObjectiveStore.getNextGroup(fwd.nextId()) == null) {