java_gen: value types: add NO_MASK, FULL_MASK constants where missing

This is necessary so types can distinguish non-canonical forms.
diff --git a/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/ClassId.java b/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/ClassId.java
index b082f8b..7d7c38e 100644
--- a/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/ClassId.java
+++ b/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/ClassId.java
@@ -14,6 +14,10 @@
     private final static int NONE_VAL = 0;
     public final static ClassId NONE = new ClassId(NONE_VAL);
 
+    private final static int NO_MASK_VAL = 0xFFFFFFFF;
+    public final static ClassId NO_MASK = new ClassId(NO_MASK_VAL);
+    public final static ClassId FULL_MASK = NONE;
+
     private final int rawValue;
 
     private ClassId(final int rawValue) {
@@ -23,7 +27,8 @@
     public static ClassId of(final int raw) {
         if(raw == NONE_VAL)
             return NONE;
-
+        else if(raw == NO_MASK_VAL)
+            return NO_MASK;
         return new ClassId(raw);
     }