diff --git a/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/IPv6WithMask.java b/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/IPv6WithMask.java
new file mode 100644
index 0000000..894a6dd
--- /dev/null
+++ b/java_gen/pre-written/src/main/java/org/projectfloodlight/openflow/types/IPv6WithMask.java
@@ -0,0 +1,91 @@
+package org.projectfloodlight.openflow.types;
+
+import java.math.BigInteger;
+import java.util.Arrays;
+
+public class IPv6WithMask extends Masked<IPv6> {
+
+    private IPv6WithMask(IPv6 value, IPv6 mask) {
+        super(value, mask);
+    }
+    
+    public static IPv6WithMask of(IPv6 value, IPv6 mask) {
+        return new IPv6WithMask(value, mask);
+    }
+    
+    @Override
+    public String toString() {
+        StringBuilder res = new StringBuilder();
+        res.append(((IPv6)value).toString());
+        res.append('/');
+        
+        BigInteger maskint = new BigInteger(((IPv6)mask).getBytes());
+        if (maskint.not().add(BigInteger.ONE).bitCount() == 1) {
+            // CIDR notation
+            res.append(maskint.bitCount());
+        } else {
+            // Full address mask
+            res.append(((IPv6)mask).toString());
+        }
+        
+        return res.toString();
+    }
+    
+    public static IPv6WithMask of(final String string) {
+        int slashPos;
+        String ip = string;
+        int maskBits = 0;
+        IPv6 maskAddress = null;
+
+        // Read mask suffix
+        if ((slashPos = string.indexOf('/')) != -1) {
+            ip = string.substring(0, slashPos);
+            try {
+                String suffix = string.substring(slashPos + 1);
+                if (suffix.length() == 0)
+                    throw new IllegalArgumentException("IPv6 Address not well formed: " + string);
+                if (suffix.indexOf(':') != -1) {
+                    // Full mask
+                    maskAddress = IPv6.of(suffix);
+                } else {
+                    // CIDR Suffix
+                    maskBits = Integer.parseInt(suffix);
+                }
+            } catch (NumberFormatException e) {
+                throw new IllegalArgumentException("IPv6 Address not well formed: " + string);
+            }
+            if (maskBits < 0 || maskBits > 128) {
+                throw new IllegalArgumentException("IPv6 Address not well formed: " + string);
+            }
+        }
+        
+        // Read IP
+        IPv6 ipv6 = IPv6.of(ip);
+        
+        if (maskAddress != null) {
+            // Full address mask
+            return IPv6WithMask.of(ipv6, maskAddress);
+        } else if (maskBits == 0) {
+            // No mask
+            return IPv6WithMask.of(ipv6, IPv6.NO_MASK);
+        } else {
+            // With mask
+            BigInteger mask = BigInteger.ONE.negate().shiftLeft(128 - maskBits);
+            byte[] maskBytesTemp = mask.toByteArray();
+            byte[] maskBytes;
+            if (maskBytesTemp.length < 16) {
+                maskBytes = new byte[16];
+                System.arraycopy(maskBytesTemp, 0, maskBytes, 16 - maskBytesTemp.length, maskBytesTemp.length);
+                Arrays.fill(maskBytes, 0, 16 - maskBytesTemp.length, (byte)(0xFF));
+            } else if (maskBytesTemp.length > 16) {
+                maskBytes = new byte[16];
+                System.arraycopy(maskBytesTemp, 0, maskBytes, 0, maskBytes.length);
+            } else {
+                maskBytes = maskBytesTemp;
+            }
+            return IPv6WithMask.of(ipv6, IPv6.of(maskBytes));
+        }
+    }
+
+
+}