Add new method FlowEntry.isValidFlowId() and the corresponding unit test.
diff --git a/src/main/java/net/onrc/onos/ofcontroller/util/FlowEntry.java b/src/main/java/net/onrc/onos/ofcontroller/util/FlowEntry.java
index 9862040..03794a1 100644
--- a/src/main/java/net/onrc/onos/ofcontroller/util/FlowEntry.java
+++ b/src/main/java/net/onrc/onos/ofcontroller/util/FlowEntry.java
@@ -116,6 +116,7 @@
 
     /**
      * Get the Flow ID.
+     *
      * @return the Flow ID.
      */
     @JsonIgnore
@@ -131,6 +132,17 @@
     }
 
     /**
+     * Test whether the Flow ID is valid.
+     *
+     * @return true if the Flow ID is valid, otherwise false.
+     */
+    public boolean isValidFlowId() {
+	if (this.flowId == null)
+	    return false;
+	return (this.flowId.value() != 0);
+    }
+
+    /**
      * Get the Flow Entry ID.
      *
      * @return the Flow Entry ID.