[ONOS-3469] Add arp_op Criteria to onos

Change-Id: I4b6c84d3a4145e698f2845d492db54d0b2e2738b
diff --git a/core/api/src/main/java/org/onosproject/net/flow/criteria/Criteria.java b/core/api/src/main/java/org/onosproject/net/flow/criteria/Criteria.java
index 554b8e7..da8e426 100644
--- a/core/api/src/main/java/org/onosproject/net/flow/criteria/Criteria.java
+++ b/core/api/src/main/java/org/onosproject/net/flow/criteria/Criteria.java
@@ -549,6 +549,16 @@
         return new ArpHaCriterion(mac, Type.ARP_SHA);
     }
 
+    /**
+     * Creates a match on arp operation type field using the specified value.
+     *
+     * @param arpOp arp operation type value
+     * @return match criterion
+     */
+    public static Criterion matchArpOp(int arpOp) {
+        return new ArpOpCriterion(arpOp, Type.ARP_OP);
+    }
+
     public static Criterion dummy() {
         return new DummyCriterion();
     }