Override toString for flow objectives

Change-Id: I725ca9ac231e21c12f364e1a8bbdc6d3cd1e5a38
diff --git a/core/api/src/main/java/org/onosproject/net/flowobjective/DefaultNextObjective.java b/core/api/src/main/java/org/onosproject/net/flowobjective/DefaultNextObjective.java
index 8010659..01a6f0d 100644
--- a/core/api/src/main/java/org/onosproject/net/flowobjective/DefaultNextObjective.java
+++ b/core/api/src/main/java/org/onosproject/net/flowobjective/DefaultNextObjective.java
@@ -26,6 +26,7 @@
 import java.util.Objects;
 import java.util.Optional;
 
+import static com.google.common.base.MoreObjects.toStringHelper;
 import static com.google.common.base.Preconditions.checkArgument;
 import static com.google.common.base.Preconditions.checkNotNull;
 
@@ -125,6 +126,22 @@
         return false;
     }
 
+    @Override
+    public String toString() {
+        return toStringHelper(this)
+                .add("id", id())
+                .add("type", type())
+                .add("op", op())
+                .add("priority", priority())
+                .add("next", next())
+                .add("meta", meta())
+                .add("appId", appId())
+                .add("permanent", permanent())
+                .add("timeout", timeout())
+                .add("context", context())
+                .toString();
+    }
+
     /**
      * Returns a new builder.
      *