Implement toString for DefaultTrafficSelector and DefaultTrafficTreatment

Change-Id: I4e9348795855bd667e8931da161427cd4a450d44
diff --git a/core/api/src/main/java/org/onlab/onos/net/flow/DefaultTrafficTreatment.java b/core/api/src/main/java/org/onlab/onos/net/flow/DefaultTrafficTreatment.java
index d202217..d3fb7d9 100644
--- a/core/api/src/main/java/org/onlab/onos/net/flow/DefaultTrafficTreatment.java
+++ b/core/api/src/main/java/org/onlab/onos/net/flow/DefaultTrafficTreatment.java
@@ -1,5 +1,9 @@
 package org.onlab.onos.net.flow;
 
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Objects;
+
 import org.onlab.onos.net.PortNumber;
 import org.onlab.onos.net.flow.instructions.Instruction;
 import org.onlab.onos.net.flow.instructions.Instructions;
@@ -7,12 +11,9 @@
 import org.onlab.packet.MacAddress;
 import org.onlab.packet.VlanId;
 
+import com.google.common.base.MoreObjects;
 import com.google.common.collect.ImmutableList;
 
-import java.util.LinkedList;
-import java.util.List;
-import java.util.Objects;
-
 /**
  * Default traffic treatment implementation.
  */
@@ -62,6 +63,13 @@
         return false;
     }
 
+    @Override
+    public String toString() {
+        return MoreObjects.toStringHelper(getClass())
+                .add("instructions", instructions)
+                .toString();
+    }
+
     /**
      * Builds a list of treatments following the following order.
      * Modifications -> Group -> Output (including drop)