diff --git a/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/ArpOpcode.java b/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/ArpOpcode.java
index 2a33a0e..88e5fe9 100644
--- a/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/ArpOpcode.java
+++ b/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/ArpOpcode.java
@@ -2,6 +2,7 @@
 
 import org.jboss.netty.buffer.ChannelBuffer;
 
+import com.google.common.hash.PrimitiveSink;
 import com.google.common.primitives.UnsignedInts;
 
 public class ArpOpcode implements OFValueType<ArpOpcode> {
@@ -189,4 +190,9 @@
         return UnsignedInts.compare(opcode, o.opcode);
     }
 
+    @Override
+    public void putTo(PrimitiveSink sink) {
+        sink.putShort((short) this.opcode);
+    }
+
 }
\ No newline at end of file