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 b840318..fa8a64c 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
@@ -55,6 +55,16 @@
     }
 
     @Override
+    public Criterion getCriterion(Criterion.Type type) {
+        for (Criterion c : criteria) {
+            if (c.type() == type) {
+                return c;
+            }
+        }
+        return null;
+    }
+
+    @Override
     public int hashCode() {
         return Objects.hash(criteria);
     }