diff --git a/java_gen/pre-written/src/main/java/org/openflow/protocol/XidGenerator.java b/java_gen/pre-written/src/main/java/org/openflow/protocol/XidGenerator.java
new file mode 100644
index 0000000..0819ac2
--- /dev/null
+++ b/java_gen/pre-written/src/main/java/org/openflow/protocol/XidGenerator.java
@@ -0,0 +1,5 @@
+package org.openflow.protocol;
+
+public interface XidGenerator {
+    int nextXid();
+}