Address review comments
diff --git a/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/IPAddressWithMask.java b/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/IPAddressWithMask.java
index 654e72c..2087ab4 100644
--- a/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/IPAddressWithMask.java
+++ b/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/IPAddressWithMask.java
@@ -27,7 +27,7 @@
         res.append(value.toString());
 
         res.append('/');
-        if (mask.asCidrMaskLength() != -1) {
+        if (mask.isCidrMask()) {
             // CIDR notation
             res.append(mask.asCidrMaskLength());
         } else {