Implement toString for DefaultTrafficSelector and DefaultTrafficTreatment

Change-Id: I4e9348795855bd667e8931da161427cd4a450d44
diff --git a/core/api/src/main/java/org/onlab/onos/net/flow/DefaultTrafficSelector.java b/core/api/src/main/java/org/onlab/onos/net/flow/DefaultTrafficSelector.java
index f51d75e..f175bd3 100644
--- a/core/api/src/main/java/org/onlab/onos/net/flow/DefaultTrafficSelector.java
+++ b/core/api/src/main/java/org/onlab/onos/net/flow/DefaultTrafficSelector.java
@@ -1,6 +1,10 @@
 package org.onlab.onos.net.flow;
 
-import com.google.common.collect.ImmutableSet;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Objects;
+import java.util.Set;
+
 import org.onlab.onos.net.PortNumber;
 import org.onlab.onos.net.flow.criteria.Criteria;
 import org.onlab.onos.net.flow.criteria.Criterion;
@@ -8,10 +12,8 @@
 import org.onlab.packet.MacAddress;
 import org.onlab.packet.VlanId;
 
-import java.util.HashMap;
-import java.util.Map;
-import java.util.Objects;
-import java.util.Set;
+import com.google.common.base.MoreObjects;
+import com.google.common.collect.ImmutableSet;
 
 /**
  * Default traffic selector implementation.
@@ -52,6 +54,13 @@
         return false;
     }
 
+    @Override
+    public String toString() {
+        return MoreObjects.toStringHelper(getClass())
+                .add("criteria", criteria)
+                .toString();
+    }
+
     /**
      * Returns a new traffic selector builder.
      *