add openflow.types.Metadata
diff --git a/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/Metadata.java b/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/Metadata.java
new file mode 100644
index 0000000..1d0aea7
--- /dev/null
+++ b/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/Metadata.java
@@ -0,0 +1,52 @@
+package org.projectfloodlight.openflow.types;
+
+import javax.annotation.concurrent.Immutable;
+
+@Immutable
+public class Metadata {
+    static final int LENGTH = 4;
+    private final int rawValue;
+
+    private Metadata(final int rawValue) {
+        this.rawValue = rawValue;
+    }
+
+    public static Metadata of(final int raw) {
+        return new Metadata(raw);
+    }
+
+    public int getInt() {
+        return rawValue;
+    }
+
+    public int getLength() {
+        return LENGTH;
+    }
+
+    @Override
+    public int hashCode() {
+        final int prime = 31;
+        int result = 1;
+        result = prime * result + rawValue;
+        return result;
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj)
+            return true;
+        if (obj == null)
+            return false;
+        if (getClass() != obj.getClass())
+            return false;
+        Metadata other = (Metadata) obj;
+        if (rawValue != other.rawValue)
+            return false;
+        return true;
+    }
+
+    @Override
+    public String toString() {
+        return Integer.toString(rawValue);
+    }
+}