diff --git a/java_gen/java_type.py b/java_gen/java_type.py
index e88458a..8580f37 100644
--- a/java_gen/java_type.py
+++ b/java_gen/java_type.py
@@ -21,6 +21,19 @@
         return camel
 
 
+ANY = 0xFFFFFFFFFFFFFFFF
+
+
+class VersionOp:
+    def __init__(self, version=ANY, read=None, write=None):
+        self.version = version
+        self.read = read
+        self.write = write
+        
+    def __str__(self):
+        return "[Version: %d, Read: '%s', Write: '%s']" % (self.version, self.read, self.write)
+
+
 class JType(object):
     """ Wrapper class to hold C to Java type conversion information """
     def __init__(self, pub_type, priv_type=None, size=None, read_op=None, write_op=None):
@@ -29,12 +42,17 @@
             priv_type = pub_type
         self.priv_type = priv_type  # the internal storage type
         self.size = size            # bytes on the wire; None == variable length or hard to calc
-        if read_op is None:
-            read_op = 'ChannelUtils.read%s(bb)' % self.pub_type
-        if write_op is None:
-            write_op = 'ChannelUtils.write%s(bb, $name)'  % self.pub_type
-        self._read_op = read_op
-        self._write_op = write_op
+        self.ops = {}
+#        if read_op is None:
+#            read_op = 'ChannelUtils.read%s(bb)' % self.pub_type
+#        if write_op is None:
+#            write_op = 'ChannelUtils.write%s(bb, $name)'  % self.pub_type
+#        self._read_op = read_op
+#        self._write_op = write_op
+
+    def op(self, version=ANY, read=None, write=None):
+        self.ops[version] = VersionOp(version, read, write)
+        return self
 
     @property
     def public_type(self):
@@ -53,105 +71,111 @@
         if length is None:
             length = "length - bb.readerIndex()";
 
-        if callable(self._read_op):
-            return self._read_op(version)
+        ver = ANY if version is None else version.int_version
+        _read_op = None
+        if ver in self.ops:
+            _read_op = self.ops[ver].read or self.ops[ANY].read 
+        elif ANY in self.ops:
+            _read_op = self.ops[ANY].read
+        if _read_op is None:
+            _read_op = 'ChannelUtils.read%s(bb)' % self.pub_type
+        if callable(_read_op):
+            return _read_op(version)
         else:
-            return self._read_op.replace("$length", str(length)).replace("$version", version.of_version)
+            return _read_op.replace("$length", str(length)).replace("$version", version.of_version)
 
     def write_op(self, version=None, name=None):
-        if callable(self._write_op):
-            return self._write_op(version, name)
+        ver = ANY if version is None else version.int_version
+        _write_op = None
+        if ver in self.ops:
+            _write_op = self.ops[ver].write or self.ops[ANY].write
+        elif ANY in self.ops:
+            _write_op = self.ops[ANY].write
+        if _write_op is None:
+            _write_op = 'ChannelUtils.write%s(bb, $name)' % self.pub_type
+        if callable(_write_op):
+            return _write_op(version, name)
         else:
-            return self._write_op.replace("$name", str(name)).replace("$version", version.of_version)
+            return _write_op.replace("$name", str(name)).replace("$version", version.of_version)
 
-hello_elem_list = JType("List<OFHelloElement>",
-        read_op = 'ChannelUtils.readHelloElementList(bb)',
-        write_op = 'ChannelUtils.writeHelloElementList(bb)'
-        )
-u8 =  JType('byte',  size=1, read_op='bb.readByte()',
-        write_op='bb.writeByte($name)')
-u8_list =  JType('List<U8>',  size=1, read_op='bb.readByte()',
-        write_op='bb.writeByte($name)')
-u16 = JType('int', 'int', size=2, read_op='U16.f(bb.readShort())',
-        write_op='bb.writeShort(U16.t($name))')
-u32 = JType('int', 'int',   size=4, read_op='bb.readInt()',
-        write_op='bb.writeInt($name)')
-u32_list = JType('List<U32>', 'int[]',   size=4, read_op='bb.readInt()',
-        write_op='bb.writeInt($name)')
-u64 = JType('U64', 'U64', size=8, read_op='U64.of(bb.readLong())',
-        write_op='bb.writeLong($name.getValue())')
-of_port= JType('OFPort',size=None,
-        read_op = "OFPort.SERIALIZER_V$version.readFrom(bb)",
-        write_op = "OFPort.SERIALIZER_V$version.writeTo($name, bb)")
-one_byte_array = JType('byte[]', size=1,
-        read_op = 'ChannelUtils.readBytes(bb, 1)',
-        write_op = 'ChannelUtils.writeBytes(bb, $name)')
-two_byte_array = JType('byte[]', size=2,
-        read_op = 'ChannelUtils.readBytes(bb, 2)',
-        write_op = 'ChannelUtils.writeBytes(bb, $name)')
-three_byte_array = JType('byte[]', size=3,
-        read_op = 'ChannelUtils.readBytes(bb, 3)',
-        write_op = 'ChannelUtils.writeBytes(bb, $name)')
-four_byte_array = JType('byte[]', size=4,
-        read_op = 'ChannelUtils.readBytes(bb, 4)',
-        write_op = 'ChannelUtils.writeBytes(bb, $name)')
-five_byte_array = JType('byte[]', size=5,
-        read_op = 'ChannelUtils.readBytes(bb, 5)',
-        write_op = 'ChannelUtils.writeBytes(bb, $name)')
-six_byte_array = JType('byte[]', size=6,
-        read_op = 'ChannelUtils.readBytes(bb, 6)',
-        write_op = 'ChannelUtils.writeBytes(bb, $name)')
-seven_byte_array = JType('byte[]', size=7,
-        read_op = 'ChannelUtils.readBytes(bb, 7)',
-        write_op = 'ChannelUtils.writeBytes(bb, $name)')
-actions_list = JType('List<OFAction>', size='ChannelUtils.calcListSize($name)',
-        read_op = 'ChannelUtils.readActionsList(bb, $length)',
-        write_op = 'ChannelUtils.writeActionsList(bb, $name);')
-instructions_list = JType('List<OFInstruction>', size='ChannelUtils.calcListSize($name)',
-        read_op = 'ChannelUtils.readInstructionsList(bb, $length)',
-        write_op = 'ChannelUtils.writeList(bb, $name)')
-buckets_list = JType('List<OFBucket>', size='ChannelUtils.calcListSize($name)',
-        read_op = 'ChannelUtils.readBucketList(bb, $length)',
-        write_op = 'ChannelUtils.writeList(bb, $name)')
-port_desc_list = JType('List<OFPhysicalPort>', size='ChannelUtils.calcListSize($name)',
-        read_op = 'ChannelUtils.readPhysicalPortList(bb, $length)',
-        write_op = 'ChannelUtils.writeList(bb, $name)')
-port_desc = JType('OFPortDesc', size='$name.getLength()',
-        read_op = 'null; // TODO OFPortDescVer$version.READER.read(bb)',
-        write_op = '$name.writeTo(bb)')
-packet_queue_list = JType('List<OFPacketQueue>', size='ChannelUtils.calcListSize($name)',
-        read_op = 'ChannelUtils.readPacketQueueList(bb, $length)',
-        write_op = 'ChannelUtils.writeList(bb, $name)')
-octets = JType('byte[]', size="$length",
-        read_op = 'ChannelUtils.readBytes(bb, $length)',
-        write_op = 'bb.writeBytes($name)')
-of_match = JType('Match', size="$name.getLength()",
-        read_op = 'ChannelUtils.readOFMatch(bb)',
-        write_op = 'ChannelUtils.writeOFMatch(bb, $name)')
-flow_mod_cmd = JType('OFFlowModCommand', 'short', size="$name.getLength()",
-        read_op = lambda v: "bb.readShort()" if v.int_version == 1 else "bb.readByte()",
-        write_op = lambda v, name: "bb.writeShort(%s)" % name if v.int_version == 1 else "bb.writeByte(%s)" % name)
-mac_addr = JType('MacAddress', 'byte[]', size=6,
-        read_op = "MacAddress.SERIALIZER_V$version.readFrom(bb)",
-        write_op = "MacAddress.SERIALIZER_V$version.writeTo($name, bb)")
-port_name = JType('String', size=16,
-        read_op = 'ChannelUtils.readFixedLengthString(bb, 16)',
-        write_op = 'ChannelUtils.writeFixedLengthString(bb, $name, 16)')
-desc_str = JType('String', size=256,
-        read_op = 'ChannelUtils.readFixedLengthString(bb, 256)',
-        write_op = 'ChannelUtils.writeFixedLengthString(bb, $name, 256)')
-serial_num = JType('String', size=32,
-        read_op = 'ChannelUtils.readFixedLengthString(bb, 32)',
-        write_op = 'ChannelUtils.writeFixedLengthString(bb, $name, 32)')
-table_name = JType('String', size=32,
-        read_op = 'ChannelUtils.readFixedLengthString(bb, 32)',
-        write_op = 'ChannelUtils.writeFixedLengthString(bb, $name, 32)')
-ipv4 = JType("IPv4",
-        read_op = "IPv4.SERIALIZER_V$version.readFrom(bb)",
-        write_op = "IPv4.SERIALIZER_V$version.writeTo($name, bb)")
-ipv6 = JType("IPv6",
-        read_op = "IPv6.SERIALIZER_V$version.readFrom(bb)",
-        write_op = "IPv6.SERIALIZER_V$version.writeTo($name, bb)")
+hello_elem_list = JType("List<OFHelloElement>") \
+        .op(read='ChannelUtils.readHelloElementList(bb)', write='ChannelUtils.writeHelloElementList(bb)')
+u8 =  JType('byte',  size=1) \
+        .op(read='bb.readByte()', write='bb.writeByte($name)')
+u8_list =  JType('List<U8>',  size=1) \
+        .op(read='bb.readByte()', write='bb.writeByte($name)')
+u16 = JType('int', 'int', size=2) \
+        .op(read='U16.f(bb.readShort())', write='bb.writeShort(U16.t($name))')
+u32 = JType('int', 'int', size=4) \
+        .op(read='bb.readInt()', write='bb.writeInt($name)')
+u32_list = JType('List<U32>', 'int[]', size=4) \
+        .op(read='bb.readInt()', write='bb.writeInt($name)')
+u64 = JType('U64', 'U64', size=8) \
+        .op(read='U64.of(bb.readLong())', write='bb.writeLong($name.getValue())')
+of_port = JType("OFPort") \
+         .op(version=1, read="OFPort.read2Bytes(bb)", write="$name.write2Bytes(bb)") \
+         .op(version=ANY, read="OFPort.read4Bytes(bb)", write="$name.write4Bytes(bb)")
+one_byte_array = JType('byte[]', size=1) \
+        .op(read='ChannelUtils.readBytes(bb, 1)', write='ChannelUtils.writeBytes(bb, $name)')
+two_byte_array = JType('byte[]', size=2) \
+        .op(read='ChannelUtils.readBytes(bb, 2)', write='ChannelUtils.writeBytes(bb, $name)')
+three_byte_array = JType('byte[]', size=3) \
+        .op(read='ChannelUtils.readBytes(bb, 3)', write='ChannelUtils.writeBytes(bb, $name)')
+four_byte_array = JType('byte[]', size=4) \
+        .op(read='ChannelUtils.readBytes(bb, 4)', write='ChannelUtils.writeBytes(bb, $name)')
+five_byte_array = JType('byte[]', size=5) \
+        .op(read='ChannelUtils.readBytes(bb, 5)', write='ChannelUtils.writeBytes(bb, $name)')
+six_byte_array = JType('byte[]', size=6) \
+        .op(read='ChannelUtils.readBytes(bb, 6)', write='ChannelUtils.writeBytes(bb, $name)')
+seven_byte_array = JType('byte[]', size=7) \
+        .op(read='ChannelUtils.readBytes(bb, 7)', write='ChannelUtils.writeBytes(bb, $name)')
+actions_list = JType('List<OFAction>', size='ChannelUtils.calcListSize($name)') \
+        .op(read='ChannelUtils.readActionsList(bb, $length)', write='ChannelUtils.writeActionsList(bb, $name);')
+instructions_list = JType('List<OFInstruction>', size='ChannelUtils.calcListSize($name)') \
+        .op(read='ChannelUtils.readInstructionsList(bb, $length)', \
+            write='ChannelUtils.writeList(bb, $name)')
+buckets_list = JType('List<OFBucket>', size='ChannelUtils.calcListSize($name)') \
+        .op(read='ChannelUtils.readBucketList(bb, $length)', \
+            write='ChannelUtils.writeList(bb, $name)')
+port_desc_list = JType('List<OFPhysicalPort>', size='ChannelUtils.calcListSize($name)') \
+        .op(read='ChannelUtils.readPhysicalPortList(bb, $length)', \
+            write='ChannelUtils.writeList(bb, $name)')
+port_desc = JType('OFPortDesc', size='$name.getLength()') \
+        .op(read='null; // TODO OFPortDescVer$version.READER.read(bb)', \
+            write='$name.writeTo(bb)')
+packet_queue_list = JType('List<OFPacketQueue>', size='ChannelUtils.calcListSize($name)') \
+        .op(read='ChannelUtils.readPacketQueueList(bb, $length)', \
+            write='ChannelUtils.writeList(bb, $name)')
+octets = JType('byte[]', size="$length") \
+        .op(read='ChannelUtils.readBytes(bb, $length)', \
+            write='bb.writeBytes($name)')
+of_match = JType('Match', size="$name.getLength()") \
+        .op(read='ChannelUtils.readOFMatch(bb)', \
+            write='ChannelUtils.writeOFMatch(bb, $name)')
+flow_mod_cmd = JType('OFFlowModCommand', 'short', size="$name.getLength()") \
+        .op(version=1, read="bb.readShort()", write="bb.writeShort($name)") \
+        .op(version=ANY, read="bb.readByte()", write="bb.writeByte($name)")
+mac_addr = JType('MacAddress', 'byte[]', size=6) \
+        .op(read="MacAddress.read6Bytes(bb)", \
+            write="$name.write6Bytes(bb)")
+port_name = JType('String', size=16) \
+        .op(read='ChannelUtils.readFixedLengthString(bb, 16)', \
+            write='ChannelUtils.writeFixedLengthString(bb, $name, 16)')
+desc_str = JType('String', size=256) \
+        .op(read='ChannelUtils.readFixedLengthString(bb, 256)', \
+            write='ChannelUtils.writeFixedLengthString(bb, $name, 256)')
+serial_num = JType('String', size=32) \
+        .op(read='ChannelUtils.readFixedLengthString(bb, 32)', \
+            write='ChannelUtils.writeFixedLengthString(bb, $name, 32)')
+table_name = JType('String', size=32) \
+        .op(read='ChannelUtils.readFixedLengthString(bb, 32)', \
+            write='ChannelUtils.writeFixedLengthString(bb, $name, 32)')
+ipv4 = JType("IPv4") \
+        .op(read="IPv4.read4Bytes(bb)", \
+            write="$name.write4Bytes(bb)")
+ipv6 = JType("IPv6") \
+        .op(read="IPv6.read16Bytes(bb)", \
+            write="$name.write16Bytes(bb)")
 
 default_mtype_to_jtype_convert_map = {
         'uint8_t' : u8,
@@ -201,10 +225,9 @@
         raise Exception("Not a recgonized standard list type declaration: %s" % c_type)
     base_name = m.group(1)
     java_base_name = name_c_to_caps_camel(base_name)
-    return JType("List<OF%s>" % java_base_name,
-        read_op = 'ChannelUtils.read%sList(bb)' % java_base_name,
-        write_op = 'ChannelUtils.write%sList(bb, $name)' % java_base_name
-        )
+    return JType("List<OF%s>" % java_base_name) \
+        .op(read='ChannelUtils.read%sList(bb)' % java_base_name, \
+            write='ChannelUtils.write%sList(bb, $name)' % java_base_name)
 
 def convert_to_jtype(obj_name, field_name, c_type):
     """ Convert from a C type ("uint_32") to a java type ("U32")
@@ -212,14 +235,14 @@
     if obj_name in exceptions and field_name in exceptions[obj_name]:
         return exceptions[obj_name][field_name]
     elif field_name == "type" and c_type == "uint8_t":
-        return JType("OFType", 'byte', size=1, read_op='bb.readByte()',
-        write_op='bb.writeByte($name)')
+        return JType("OFType", 'byte', size=1) \
+            .op(read='bb.readByte()', write='bb.writeByte($name)')
     elif field_name == "type" and re.match(r'of_action.*', obj_name):
-        return JType("OFActionType", 'short', size=2, read_op='bb.readShort()',
-        write_op='bb.writeShort($name)')
+        return JType("OFActionType", 'short', size=2) \
+            .op(read='bb.readShort()', write='bb.writeShort($name)')
     elif field_name == "version" and c_type == "uint8_t":
-        return JType("OFVersion", 'byte', size=1, read_op='bb.readByte()',
-        write_op='bb.writeByte($name)')
+        return JType("OFVersion", 'byte', size=1) \
+            .op(read='bb.readByte()', write='bb.writeByte($name)')
     elif c_type in default_mtype_to_jtype_convert_map:
         return default_mtype_to_jtype_convert_map[c_type]
     elif re.match(r'list\(of_([a-zA-Z_]+)_t\)', c_type):
diff --git a/java_gen/pre-written/src/main/java/org/openflow/protocol/match/Match.java b/java_gen/pre-written/src/main/java/org/openflow/protocol/match/Match.java
index 5c1e7b5..fa42737 100644
--- a/java_gen/pre-written/src/main/java/org/openflow/protocol/match/Match.java
+++ b/java_gen/pre-written/src/main/java/org/openflow/protocol/match/Match.java
@@ -1,21 +1,20 @@
 package org.openflow.protocol.match;
 
 import org.openflow.protocol.OFObject;
+import org.openflow.types.OFValueType;
 
 public interface Match extends OFObject {
-    public <F> F get(MatchField<F, ?> match);
+    public <F extends OFValueType> F get(MatchField<F> match);
 
-    public <M> M getMasked(MatchField<?, M> match);
+    public boolean supports(MatchField<?> field);
 
-    public boolean supports(MatchField<?, ?> field);
+    public boolean supportsMasked(MatchField<?> field);
 
-    public boolean supportsMasked(MatchField<?, ?> field);
+    public boolean isExact(MatchField<?> field);
 
-    public boolean isExact(MatchField<?, ?> field);
+    public boolean isFullyWildcarded(MatchField<?> field);
 
-    public boolean isFullyWildcarded(MatchField<?, ?> field);
-
-    public boolean isPartiallyMasked(MatchField<?, ?> field);
+    public boolean isPartiallyMasked(MatchField<?> field);
 
     public MatchBuilder getBuilder();
 }
diff --git a/java_gen/pre-written/src/main/java/org/openflow/protocol/match/MatchBuilder.java b/java_gen/pre-written/src/main/java/org/openflow/protocol/match/MatchBuilder.java
index 7a5e57c..3c601f8 100644
--- a/java_gen/pre-written/src/main/java/org/openflow/protocol/match/MatchBuilder.java
+++ b/java_gen/pre-written/src/main/java/org/openflow/protocol/match/MatchBuilder.java
@@ -1,9 +1,11 @@
 package org.openflow.protocol.match;
 
-public interface MatchBuilder extends Match {
-    public <F> MatchBuilder set(MatchField<F, ?> match, F value);
+import org.openflow.types.OFValueType;
 
-    public <M> void setMasked(MatchField<?, M> match, M value);
+public interface MatchBuilder extends Match {
+    public <F extends OFValueType> MatchBuilder set(MatchField<F> match, F value);
+
+    //public <M> void setMasked(MatchField<?, M> match, M value);
 
     public Match getMatch();
 }
diff --git a/java_gen/pre-written/src/main/java/org/openflow/protocol/match/MatchBuilderVer10.java b/java_gen/pre-written/src/main/java/org/openflow/protocol/match/MatchBuilderVer10.java
index f00e1b4..0fbe84b 100644
--- a/java_gen/pre-written/src/main/java/org/openflow/protocol/match/MatchBuilderVer10.java
+++ b/java_gen/pre-written/src/main/java/org/openflow/protocol/match/MatchBuilderVer10.java
@@ -1,12 +1,13 @@
 package org.openflow.protocol.match;
 
 import org.jboss.netty.buffer.ChannelBuffer;
-import org.openflow.protocol.types.IpDscp;
 import org.openflow.types.EthType;
 import org.openflow.types.IPv4;
+import org.openflow.types.IpDscp;
 import org.openflow.types.IpProtocol;
 import org.openflow.types.MacAddress;
 import org.openflow.types.OFPort;
+import org.openflow.types.OFValueType;
 import org.openflow.types.U16;
 import org.openflow.types.VlanPcp;
 import org.openflow.types.VlanVid;
@@ -65,7 +66,7 @@
 
     @SuppressWarnings("unchecked")
     @Override
-    public <F> F get(final MatchField<F, ?> match) {
+    public <F extends OFValueType> F get(final MatchField<F> match) {
         switch (match.id) {
             case 0:
                 return (F) inputPort;
@@ -78,7 +79,7 @@
 
     @SuppressWarnings("unchecked")
     @Override
-    public <F> MatchBuilder set(final MatchField<F, ?> match, final F value) {
+    public <F extends OFValueType> MatchBuilder set(final MatchField<F> match, final F value) {
         switch (match.id) {
             case 0:
                 inputPort = (OFPort) value;
@@ -107,37 +108,31 @@
     }
 
     @Override
-    public <M> M getMasked(final MatchField<?, M> match) {
-        // TODO Auto-generated method stub
-        return null;
-    }
-
-    @Override
-    public boolean supports(final MatchField<?, ?> field) {
+    public boolean supports(final MatchField<?> field) {
         // TODO Auto-generated method stub
         return false;
     }
 
     @Override
-    public boolean supportsMasked(final MatchField<?, ?> field) {
+    public boolean supportsMasked(final MatchField<?> field) {
         // TODO Auto-generated method stub
         return false;
     }
 
     @Override
-    public boolean isExact(final MatchField<?, ?> field) {
+    public boolean isExact(final MatchField<?> field) {
         // TODO Auto-generated method stub
         return false;
     }
 
     @Override
-    public boolean isFullyWildcarded(final MatchField<?, ?> field) {
+    public boolean isFullyWildcarded(final MatchField<?> field) {
         // TODO Auto-generated method stub
         return false;
     }
 
     @Override
-    public boolean isPartiallyMasked(final MatchField<?, ?> field) {
+    public boolean isPartiallyMasked(final MatchField<?> field) {
         // TODO Auto-generated method stub
         return false;
     }
@@ -159,13 +154,13 @@
         // TODO Auto-generated method stub
 
     }
-
+/*
     @Override
     public <M> void setMasked(final MatchField<?, M> match, final M value) {
         // TODO Auto-generated method stub
 
     }
-
+*/
     @Override
     public Match getMatch() {
         // TODO Auto-generated method stub
diff --git a/java_gen/pre-written/src/main/java/org/openflow/protocol/match/MatchField.java b/java_gen/pre-written/src/main/java/org/openflow/protocol/match/MatchField.java
index cc191ab..d9d68ec 100644
--- a/java_gen/pre-written/src/main/java/org/openflow/protocol/match/MatchField.java
+++ b/java_gen/pre-written/src/main/java/org/openflow/protocol/match/MatchField.java
@@ -1,18 +1,24 @@
 package org.openflow.protocol.match;
 
+import org.openflow.types.ArpOpcode;
 import org.openflow.types.EthType;
-import org.openflow.types.IPv4;
-import org.openflow.types.IPv6;
+import org.openflow.types.ICMPv4Code;
+import org.openflow.types.ICMPv4Type;
+import org.openflow.types.IPv4WithMask;
+import org.openflow.types.IPv6FlowLabel;
+import org.openflow.types.IPv6WithMask;
+import org.openflow.types.IpDscp;
+import org.openflow.types.IpEcn;
 import org.openflow.types.IpProtocol;
 import org.openflow.types.MacAddress;
 import org.openflow.types.Masked;
 import org.openflow.types.OFPort;
-import org.openflow.types.U16;
-import org.openflow.types.U8;
+import org.openflow.types.OFValueType;
+import org.openflow.types.TransportPort;
 import org.openflow.types.VlanPcp;
 import org.openflow.types.VlanVid;
 
-public class MatchField<F, M> {
+public class MatchField<F extends OFValueType> {
     private final String name;
     public final int id;
 
@@ -26,78 +32,77 @@
         this.id = id;
     }
 
-    public final static MatchField<OFPort, NoMatch> IN_PORT =
-            new MatchField<OFPort, NoMatch>("in_port", 0);
-    public final static MatchField<OFPort, NoMatch> IN_PHY_PORT =
-            new MatchField<OFPort, NoMatch>("in_phy_port");
-    public final static MatchField<OFPort, NoMatch> METADATA =
-            new MatchField<OFPort, NoMatch>("metadata");
+    public final static MatchField<OFPort> IN_PORT =
+            new MatchField<OFPort>("in_port", 0);
+    public final static MatchField<OFPort> IN_PHY_PORT =
+            new MatchField<OFPort>("in_phy_port");
+    public final static MatchField<OFPort> METADATA =
+            new MatchField<OFPort>("metadata");
 
-    public final static MatchField<MacAddress, Masked<MacAddress>> ETH_DST =
-            new MatchField<MacAddress, Masked<MacAddress>>("eth_dst");
-    public final static MatchField<MacAddress, Masked<MacAddress>> ETH_SRC =
-            new MatchField<MacAddress, Masked<MacAddress>>("eth_src", 1);
+    public final static MatchField<Masked<MacAddress>> ETH_DST =
+            new MatchField<Masked<MacAddress>>("eth_dst");
+    public final static MatchField<Masked<MacAddress>> ETH_SRC =
+            new MatchField<Masked<MacAddress>>("eth_src", 1);
 
-    public final static MatchField<EthType, NoMatch> ETH_TYPE =
-            new MatchField<EthType, NoMatch>("eth_type");
+    public final static MatchField<EthType> ETH_TYPE =
+            new MatchField<EthType>("eth_type");
     
-    public final static MatchField<VlanVid, Masked<VlanVid>> VLAN_VID =
-            new MatchField<VlanVid, Masked<VlanVid>>("vlan_vid");
-    public final static MatchField<VlanPcp, NoMatch> VLAN_PCP =
-            new MatchField<VlanPcp, NoMatch>("vlan_pcp");
+    public final static MatchField<Masked<VlanVid>> VLAN_VID =
+            new MatchField<Masked<VlanVid>>("vlan_vid");
+    public final static MatchField<VlanPcp> VLAN_PCP =
+            new MatchField<VlanPcp>("vlan_pcp");
     
     
-    public final static MatchField<NoMatch, NoMatch> IP_DSCP =
-            new MatchField<NoMatch, NoMatch>("ip_dscp");
-    public final static MatchField<NoMatch, NoMatch> IP_ECN =
-            new MatchField<NoMatch, NoMatch>("ip_dscp");
-    public final static MatchField<IpProtocol, NoMatch> IP_PROTO =
-            new MatchField<IpProtocol, NoMatch>("ip_proto");
+    public final static MatchField<IpDscp> IP_DSCP =
+            new MatchField<IpDscp>("ip_dscp");
+    public final static MatchField<IpEcn> IP_ECN =
+            new MatchField<IpEcn>("ip_dscp");
+    public final static MatchField<IpProtocol> IP_PROTO =
+            new MatchField<IpProtocol>("ip_proto");
 
-    public final static MatchField<IPv4, Masked<IPv4>> IPV4_SRC =
-            new MatchField<IPv4, Masked<IPv4>>("ipv4_src");
-    public final static MatchField<IPv4, Masked<IPv4>> IPV4_DST =
-            new MatchField<IPv4, Masked<IPv4>>("ipv4_dst");
+    public final static MatchField<IPv4WithMask> IPV4_SRC =
+            new MatchField<IPv4WithMask>("ipv4_src");
+    public final static MatchField<IPv4WithMask> IPV4_DST =
+            new MatchField<IPv4WithMask>("ipv4_dst");
 
-    public final static MatchField<U16, NoMatch> TCP_SRC = new MatchField<U16, NoMatch>(
+    public final static MatchField<TransportPort> TCP_SRC = new MatchField<TransportPort>(
             "tcp_src");
-    public final static MatchField<U16, NoMatch> TCP_DST = new MatchField<U16, NoMatch>(
+    public final static MatchField<TransportPort> TCP_DST = new MatchField<TransportPort>(
             "tcp_dst");
 
-    public final static MatchField<U16, NoMatch> UDP_SRC = new MatchField<U16, NoMatch>(
+    public final static MatchField<TransportPort> UDP_SRC = new MatchField<TransportPort>(
             "udp_src");
-    public final static MatchField<U16, NoMatch> UDP_DST = new MatchField<U16, NoMatch>(
+    public final static MatchField<TransportPort> UDP_DST = new MatchField<TransportPort>(
             "udp_dst");
 
-    public final static MatchField<U16, NoMatch> SCTP_SRC = new MatchField<U16, NoMatch>(
+    public final static MatchField<TransportPort> SCTP_SRC = new MatchField<TransportPort>(
             "sctp_src");
-    public final static MatchField<U16, NoMatch> SCTP_DST = new MatchField<U16, NoMatch>(
+    public final static MatchField<TransportPort> SCTP_DST = new MatchField<TransportPort>(
             "sctp_dst");
 
-    public final static MatchField<U8, NoMatch> ICMPV4_TYPE = new MatchField<U8, NoMatch>(
+    public final static MatchField<ICMPv4Type> ICMPV4_TYPE = new MatchField<ICMPv4Type>(
             "icmpv4_src");
-    public final static MatchField<U8, NoMatch> ICMPV4_CODE = new MatchField<U8, NoMatch>(
+    public final static MatchField<ICMPv4Code> ICMPV4_CODE = new MatchField<ICMPv4Code>(
             "icmpv4_dst");
 
-    public final static MatchField<U16, NoMatch> ARP_OP = new MatchField<U16, NoMatch>(
+    public final static MatchField<ArpOpcode> ARP_OP = new MatchField<ArpOpcode>(
             "arp_op");
-    public final static MatchField<IPv4, Masked<IPv4>> ARP_SPA =
-            new MatchField<IPv4, Masked<IPv4>>("arp_spa");
-    public final static MatchField<IPv4, Masked<IPv4>> ARP_TPA =
-            new MatchField<IPv4, Masked<IPv4>>("arp_tpa");
-    public final static MatchField<MacAddress, Masked<MacAddress>> ARP_SHA =
-            new MatchField<MacAddress, Masked<MacAddress>>("arp_sha");
-    public final static MatchField<MacAddress, Masked<MacAddress>> ARP_THA =
-            new MatchField<MacAddress, Masked<MacAddress>>("arp_tha");
+    public final static MatchField<IPv4WithMask> ARP_SPA =
+            new MatchField<IPv4WithMask>("arp_spa");
+    public final static MatchField<IPv4WithMask> ARP_TPA =
+            new MatchField<IPv4WithMask>("arp_tpa");
+    public final static MatchField<Masked<MacAddress>> ARP_SHA =
+            new MatchField<Masked<MacAddress>>("arp_sha");
+    public final static MatchField<Masked<MacAddress>> ARP_THA =
+            new MatchField<Masked<MacAddress>>("arp_tha");
 
-    public final static MatchField<IPv6, Masked<IPv6>> IPV6_SRC =
-            new MatchField<IPv6, Masked<IPv6>>("ipv6_src");
-    public final static MatchField<IPv6, Masked<IPv6>> IPV6_DST =
-            new MatchField<IPv6, Masked<IPv6>>("ipv6_dst");
+    public final static MatchField<IPv6WithMask> IPV6_SRC =
+            new MatchField<IPv6WithMask>("ipv6_src");
+    public final static MatchField<IPv6WithMask> IPV6_DST =
+            new MatchField<IPv6WithMask>("ipv6_dst");
 
-    // FIXME: Wrong masked type?
-    public final static MatchField<U8, Masked<IPv6>> IPV6_FLABEL =
-            new MatchField<U8, Masked<IPv6>>("ipv6_flabel");
+    public final static MatchField<Masked<IPv6FlowLabel>> IPV6_FLABEL =
+            new MatchField<Masked<IPv6FlowLabel>>("ipv6_flabel");
 
     public String getName() {
         return name;
diff --git a/java_gen/pre-written/src/main/java/org/openflow/protocol/match/NoMatch.java b/java_gen/pre-written/src/main/java/org/openflow/protocol/match/NoMatch.java
deleted file mode 100644
index b314a59..0000000
--- a/java_gen/pre-written/src/main/java/org/openflow/protocol/match/NoMatch.java
+++ /dev/null
@@ -1,5 +0,0 @@
-package org.openflow.protocol.match;
-
-public class NoMatch {
-
-}
diff --git a/java_gen/pre-written/src/main/java/org/openflow/protocol/types/IpDscp.java b/java_gen/pre-written/src/main/java/org/openflow/protocol/types/IpDscp.java
deleted file mode 100644
index dcc242a..0000000
--- a/java_gen/pre-written/src/main/java/org/openflow/protocol/types/IpDscp.java
+++ /dev/null
@@ -1,5 +0,0 @@
-package org.openflow.protocol.types;
-
-public class IpDscp {
-
-}
diff --git a/java_gen/pre-written/src/main/java/org/openflow/types/ArpOpcode.java b/java_gen/pre-written/src/main/java/org/openflow/types/ArpOpcode.java
new file mode 100644
index 0000000..852aa20
--- /dev/null
+++ b/java_gen/pre-written/src/main/java/org/openflow/types/ArpOpcode.java
@@ -0,0 +1,145 @@
+package org.openflow.types;
+
+import org.jboss.netty.buffer.ChannelBuffer;
+
+public class ArpOpcode implements OFValueType {
+
+    final static int LENGTH = 2;
+
+    private static final int ARP_OPCODE_VAL_REQUEST   = 1;
+    private static final int ARP_OPCODE_VAL_REPLY = 2;
+    private static final int ARP_OPCODE_VAL_REQUEST_REVERSE   = 3;
+    private static final int ARP_OPCODE_VAL_REPLY_REVERSE = 4;
+    private static final int ARP_OPCODE_VAL_DRARP_REQUEST = 5;
+    private static final int ARP_OPCODE_VAL_DRARP_REPLY   = 6;
+    private static final int ARP_OPCODE_VAL_DRARP_ERROR   = 7;
+    private static final int ARP_OPCODE_VAL_INARP_REQUEST = 8;
+    private static final int ARP_OPCODE_VAL_INARP_REPLY   = 9;
+    private static final int ARP_OPCODE_VAL_ARP_NAK   = 10;
+    private static final int ARP_OPCODE_VAL_MARS_REQUEST  = 11;
+    private static final int ARP_OPCODE_VAL_MARS_MULTI    = 12;
+    private static final int ARP_OPCODE_VAL_MARS_MSERV    = 13;
+    private static final int ARP_OPCODE_VAL_MARS_JOIN = 14;
+    private static final int ARP_OPCODE_VAL_MARS_LEAVE    = 15;
+    private static final int ARP_OPCODE_VAL_MARS_NAK  = 16;
+    private static final int ARP_OPCODE_VAL_MARS_UNSERV   = 17;
+    private static final int ARP_OPCODE_VAL_MARS_SJOIN    = 18;
+    private static final int ARP_OPCODE_VAL_MARS_SLEAVE   = 19;
+    private static final int ARP_OPCODE_VAL_MARS_GROUPLIST_REQUEST    = 20;
+    private static final int ARP_OPCODE_VAL_MARS_GROUPLIST_REPLY  = 21;
+    private static final int ARP_OPCODE_VAL_MARS_REDIRECT_MAP = 22;
+    private static final int ARP_OPCODE_VAL_MAPOS_UNARP   = 23;
+    private static final int ARP_OPCODE_VAL_OP_EXP1   = 24;
+    private static final int ARP_OPCODE_VAL_OP_EXP2   = 25;
+
+    public static ArpOpcode ARP_OPCODE_REQUEST  = new ArpOpcode(ARP_OPCODE_VAL_REQUEST);
+    public static ArpOpcode ARP_OPCODE_REPLY    = new ArpOpcode(ARP_OPCODE_VAL_REPLY);
+    public static ArpOpcode ARP_OPCODE_REQUEST_REVERSE  = new ArpOpcode(ARP_OPCODE_VAL_REQUEST_REVERSE);
+    public static ArpOpcode ARP_OPCODE_REPLY_REVERSE    = new ArpOpcode(ARP_OPCODE_VAL_REPLY_REVERSE);
+    public static ArpOpcode ARP_OPCODE_DRARP_REQUEST    = new ArpOpcode(ARP_OPCODE_VAL_DRARP_REQUEST);
+    public static ArpOpcode ARP_OPCODE_DRARP_REPLY  = new ArpOpcode(ARP_OPCODE_VAL_DRARP_REPLY);
+    public static ArpOpcode ARP_OPCODE_DRARP_ERROR  = new ArpOpcode(ARP_OPCODE_VAL_DRARP_ERROR);
+    public static ArpOpcode ARP_OPCODE_INARP_REQUEST    = new ArpOpcode(ARP_OPCODE_VAL_INARP_REQUEST);
+    public static ArpOpcode ARP_OPCODE_INARP_REPLY  = new ArpOpcode(ARP_OPCODE_VAL_INARP_REPLY);
+    public static ArpOpcode ARP_OPCODE_ARP_NAK  = new ArpOpcode(ARP_OPCODE_VAL_ARP_NAK);
+    public static ArpOpcode ARP_OPCODE_MARS_REQUEST = new ArpOpcode(ARP_OPCODE_VAL_MARS_REQUEST);
+    public static ArpOpcode ARP_OPCODE_MARS_MULTI   = new ArpOpcode(ARP_OPCODE_VAL_MARS_MULTI);
+    public static ArpOpcode ARP_OPCODE_MARS_MSERV   = new ArpOpcode(ARP_OPCODE_VAL_MARS_MSERV);
+    public static ArpOpcode ARP_OPCODE_MARS_JOIN    = new ArpOpcode(ARP_OPCODE_VAL_MARS_JOIN);
+    public static ArpOpcode ARP_OPCODE_MARS_LEAVE   = new ArpOpcode(ARP_OPCODE_VAL_MARS_LEAVE);
+    public static ArpOpcode ARP_OPCODE_MARS_NAK = new ArpOpcode(ARP_OPCODE_VAL_MARS_NAK);
+    public static ArpOpcode ARP_OPCODE_MARS_UNSERV  = new ArpOpcode(ARP_OPCODE_VAL_MARS_UNSERV);
+    public static ArpOpcode ARP_OPCODE_MARS_SJOIN   = new ArpOpcode(ARP_OPCODE_VAL_MARS_SJOIN);
+    public static ArpOpcode ARP_OPCODE_MARS_SLEAVE  = new ArpOpcode(ARP_OPCODE_VAL_MARS_SLEAVE);
+    public static ArpOpcode ARP_OPCODE_MARS_GROUPLIST_REQUEST   = new ArpOpcode(ARP_OPCODE_VAL_MARS_GROUPLIST_REQUEST);
+    public static ArpOpcode ARP_OPCODE_MARS_GROUPLIST_REPLY = new ArpOpcode(ARP_OPCODE_VAL_MARS_GROUPLIST_REPLY);
+    public static ArpOpcode ARP_OPCODE_MARS_REDIRECT_MAP    = new ArpOpcode(ARP_OPCODE_VAL_MARS_REDIRECT_MAP);
+    public static ArpOpcode ARP_OPCODE_MAPOS_UNARP  = new ArpOpcode(ARP_OPCODE_VAL_MAPOS_UNARP);
+    public static ArpOpcode ARP_OPCODE_OP_EXP1  = new ArpOpcode(ARP_OPCODE_VAL_OP_EXP1);
+    public static ArpOpcode ARP_OPCODE_OP_EXP2  = new ArpOpcode(ARP_OPCODE_VAL_OP_EXP2);
+
+    private static final int MIN_OPCODE = 0;
+    private static final int MAX_OPCODE = 0xFFFF;
+
+    private final int opcode;
+
+    private ArpOpcode(int opcode) {
+        this.opcode = opcode;
+    }
+
+    @Override
+    public int getLength() {
+        return LENGTH;
+    }
+
+    public int getOpcode() {
+        return this.opcode;
+    }
+
+    public static ArpOpcode of(int opcode) {
+        if (opcode < MIN_OPCODE || opcode > MAX_OPCODE)
+            throw new IllegalArgumentException("Invalid ARP opcode: " + opcode);
+        switch (opcode) {
+            case ARP_OPCODE_VAL_REQUEST:
+                return ARP_OPCODE_REQUEST;
+            case ARP_OPCODE_VAL_REPLY:
+                return ARP_OPCODE_REPLY;
+            case ARP_OPCODE_VAL_REQUEST_REVERSE:
+                return ARP_OPCODE_REQUEST_REVERSE;
+            case ARP_OPCODE_VAL_REPLY_REVERSE:
+                return ARP_OPCODE_REPLY_REVERSE;
+            case ARP_OPCODE_VAL_DRARP_REQUEST:
+                return ARP_OPCODE_DRARP_REQUEST;
+            case ARP_OPCODE_VAL_DRARP_REPLY:
+                return ARP_OPCODE_DRARP_REPLY;
+            case ARP_OPCODE_VAL_DRARP_ERROR:
+                return ARP_OPCODE_DRARP_ERROR;
+            case ARP_OPCODE_VAL_INARP_REQUEST:
+                return ARP_OPCODE_INARP_REQUEST;
+            case ARP_OPCODE_VAL_INARP_REPLY:
+                return ARP_OPCODE_INARP_REPLY;
+            case ARP_OPCODE_VAL_ARP_NAK:
+                return ARP_OPCODE_ARP_NAK;
+            case ARP_OPCODE_VAL_MARS_REQUEST:
+                return ARP_OPCODE_MARS_REQUEST;
+            case ARP_OPCODE_VAL_MARS_MULTI:
+                return ARP_OPCODE_MARS_MULTI;
+            case ARP_OPCODE_VAL_MARS_MSERV:
+                return ARP_OPCODE_MARS_MSERV;
+            case ARP_OPCODE_VAL_MARS_JOIN:
+                return ARP_OPCODE_MARS_JOIN;
+            case ARP_OPCODE_VAL_MARS_LEAVE:
+                return ARP_OPCODE_MARS_LEAVE;
+            case ARP_OPCODE_VAL_MARS_NAK:
+                return ARP_OPCODE_MARS_NAK;
+            case ARP_OPCODE_VAL_MARS_UNSERV:
+                return ARP_OPCODE_MARS_UNSERV;
+            case ARP_OPCODE_VAL_MARS_SJOIN:
+                return ARP_OPCODE_MARS_SJOIN;
+            case ARP_OPCODE_VAL_MARS_SLEAVE:
+                return ARP_OPCODE_MARS_SLEAVE;
+            case ARP_OPCODE_VAL_MARS_GROUPLIST_REQUEST:
+                return ARP_OPCODE_MARS_GROUPLIST_REQUEST;
+            case ARP_OPCODE_VAL_MARS_GROUPLIST_REPLY:
+                return ARP_OPCODE_MARS_GROUPLIST_REPLY;
+            case ARP_OPCODE_VAL_MARS_REDIRECT_MAP:
+                return ARP_OPCODE_MARS_REDIRECT_MAP;
+            case ARP_OPCODE_VAL_MAPOS_UNARP:
+                return ARP_OPCODE_MAPOS_UNARP;
+            case ARP_OPCODE_VAL_OP_EXP1:
+                return ARP_OPCODE_OP_EXP1;
+            case ARP_OPCODE_VAL_OP_EXP2:
+                return ARP_OPCODE_OP_EXP2;
+            default:
+                return new ArpOpcode(opcode);
+        }
+    }
+    
+    public void write2Bytes(ChannelBuffer c) {
+        c.writeShort(this.opcode);
+    }
+    
+    public static ArpOpcode read2Bytes(ChannelBuffer c) {
+        return ArpOpcode.of(c.readUnsignedShort());
+    }
+}
\ No newline at end of file
diff --git a/java_gen/pre-written/src/main/java/org/openflow/types/EthType.java b/java_gen/pre-written/src/main/java/org/openflow/types/EthType.java
index b86a38f..f0f0a2c 100644
--- a/java_gen/pre-written/src/main/java/org/openflow/types/EthType.java
+++ b/java_gen/pre-written/src/main/java/org/openflow/types/EthType.java
@@ -1,7 +1,7 @@
 package org.openflow.types;
 
 import org.jboss.netty.buffer.ChannelBuffer;
-import org.openflow.exceptions.OFParseError;
+
 
 /**
  * EtherType field representation.
@@ -110,23 +110,6 @@
         return LENGTH;
     }
 
-    volatile byte[] bytesCache = null;
-
-    @Override
-    public byte[] getBytes() {
-        if (bytesCache == null) {
-            synchronized (this) {
-                if (bytesCache == null) {
-                    bytesCache = new byte[] {
-                                             (byte) ((rawValue >>> 8) & 0xFF),
-                                             (byte) ((rawValue >>> 0) & 0xFF)
-                    };
-                }
-            }
-        }
-        return bytesCache;
-    }
-
     public static EthType of(int type) {
         switch (type) {
             case ETH_TYPE_VAL_IPv4:
@@ -243,24 +226,13 @@
     public String toString() {
         return Integer.toHexString(rawValue);
     }
-
-    public static final Serializer<EthType> SERIALIZER_V10 = new SerializerV10();
-    public static final Serializer<EthType> SERIALIZER_V11 = SERIALIZER_V10;
-    public static final Serializer<EthType> SERIALIZER_V12 = SERIALIZER_V10;
-    public static final Serializer<EthType> SERIALIZER_V13 = SERIALIZER_V10;
-
-    private static class SerializerV10 implements OFValueType.Serializer<EthType> {
-
-        @Override
-        public void writeTo(EthType value, ChannelBuffer c) {
-            c.writeShort(value.rawValue);
-        }
-
-        @Override
-        public EthType readFrom(ChannelBuffer c) throws OFParseError {
-            return EthType.of(c.readUnsignedShort());
-        }
-
+    
+    public void write2Bytes(ChannelBuffer c) {
+        c.writeShort(this.rawValue);
+    }
+    
+    public static EthType read2Bytes(ChannelBuffer c) {
+        return EthType.of(c.readUnsignedShort());
     }
 
 }
diff --git a/java_gen/pre-written/src/main/java/org/openflow/types/ICMPv4Code.java b/java_gen/pre-written/src/main/java/org/openflow/types/ICMPv4Code.java
new file mode 100644
index 0000000..147b5f7
--- /dev/null
+++ b/java_gen/pre-written/src/main/java/org/openflow/types/ICMPv4Code.java
@@ -0,0 +1,44 @@
+package org.openflow.types;
+
+import org.jboss.netty.buffer.ChannelBuffer;
+
+/**
+ * 
+ * @author Yotam Harchol (yotam.harchol@bigswitch.com)
+ *
+ */
+public class ICMPv4Code implements OFValueType {
+
+    final static int LENGTH = 1;
+    final static short MAX_CODE = 0xFF;
+
+    private final short code;
+
+    private ICMPv4Code(short code) {
+        this.code = code;
+    }
+
+    public static ICMPv4Code of(short code) {
+        if (code > MAX_CODE || code < 0)
+            throw new IllegalArgumentException("Illegal ICMPv4 code: " + code);
+        return new ICMPv4Code(code);
+    }
+
+    @Override
+    public int getLength() {
+        return LENGTH;
+    }
+    
+    public short getCode() {
+        return code;
+    }
+    
+    public void writeByte(ChannelBuffer c) {
+        c.writeByte(this.code);
+    }
+    
+    public static ICMPv4Code readByte(ChannelBuffer c) {
+        return ICMPv4Code.of(c.readUnsignedByte());
+    }
+
+}
diff --git a/java_gen/pre-written/src/main/java/org/openflow/types/ICMPv4Type.java b/java_gen/pre-written/src/main/java/org/openflow/types/ICMPv4Type.java
new file mode 100644
index 0000000..01d6e8f
--- /dev/null
+++ b/java_gen/pre-written/src/main/java/org/openflow/types/ICMPv4Type.java
@@ -0,0 +1,158 @@
+package org.openflow.types;
+
+import org.jboss.netty.buffer.ChannelBuffer;
+
+public class ICMPv4Type implements OFValueType {
+
+    final static int LENGTH = 1;
+
+    private static final short ICMPV4_TYPE_VAL_ECHO_REPLY    = 0;
+    private static final short ICMPV4_TYPE_VAL_DESTINATION_UNREACHABLE   = 3;
+    private static final short ICMPV4_TYPE_VAL_SOURCE_QUENCH = 4;
+    private static final short ICMPV4_TYPE_VAL_REDIRECT  = 5;
+    private static final short ICMPV4_TYPE_VAL_ALTERNATE_HOST_ADDRESS    = 6;
+    private static final short ICMPV4_TYPE_VAL_ECHO  = 8;
+    private static final short ICMPV4_TYPE_VAL_ROUTER_ADVERTISEMENT  = 9;
+    private static final short ICMPV4_TYPE_VAL_ROUTER_SOLICITATION   = 10;
+    private static final short ICMPV4_TYPE_VAL_TIME_EXCEEDED = 11;
+    private static final short ICMPV4_TYPE_VAL_PARAMETER_PROBLEM = 12;
+    private static final short ICMPV4_TYPE_VAL_TIMESTAMP = 13;
+    private static final short ICMPV4_TYPE_VAL_TIMESTAMP_REPLY   = 14;
+    private static final short ICMPV4_TYPE_VAL_INFORMATION_REQUEST   = 15;
+    private static final short ICMPV4_TYPE_VAL_INFORMATION_REPLY = 16;
+    private static final short ICMPV4_TYPE_VAL_ADDRESS_MASK_REQUEST  = 17;
+    private static final short ICMPV4_TYPE_VAL_ADDRESS_MASK_REPLY    = 18;
+    private static final short ICMPV4_TYPE_VAL_TRACEROUTE    = 30;
+    private static final short ICMPV4_TYPE_VAL_DATAGRAM_CONVERSION_ERROR = 31;
+    private static final short ICMPV4_TYPE_VAL_MOBILE_HOST_REDIRECT  = 32;
+    private static final short ICMPV4_TYPE_VAL_IPV6_WHERE_ARE_YOU    = 33;
+    private static final short ICMPV4_TYPE_VAL_IPV6_I_AM_HERE    = 34;
+    private static final short ICMPV4_TYPE_VAL_MOBILE_REGISTRATION_REQUEST   = 35;
+    private static final short ICMPV4_TYPE_VAL_MOBILE_REGISTRATION_REPLY = 36;
+    private static final short ICMPV4_TYPE_VAL_DOMAIN_NAME_REQUEST   = 37;
+    private static final short ICMPV4_TYPE_VAL_DOMAIN_NAME_REPLY = 38;
+    private static final short ICMPV4_TYPE_VAL_SKIP  = 39;
+    private static final short ICMPV4_TYPE_VAL_PHOTURIS  = 40;
+    private static final short ICMPV4_TYPE_VAL_EXPERIMENTAL_MOBILITY = 41;
+
+    public static final ICMPv4Type ICMPV4_TYPE_ECHO_REPLY   = new ICMPv4Type(ICMPV4_TYPE_VAL_ECHO_REPLY);
+    public static final ICMPv4Type ICMPV4_TYPE_DESTINATION_UNREACHABLE  = new ICMPv4Type(ICMPV4_TYPE_VAL_DESTINATION_UNREACHABLE);
+    public static final ICMPv4Type ICMPV4_TYPE_SOURCE_QUENCH    = new ICMPv4Type(ICMPV4_TYPE_VAL_SOURCE_QUENCH);
+    public static final ICMPv4Type ICMPV4_TYPE_REDIRECT = new ICMPv4Type(ICMPV4_TYPE_VAL_REDIRECT);
+    public static final ICMPv4Type ICMPV4_TYPE_ALTERNATE_HOST_ADDRESS   = new ICMPv4Type(ICMPV4_TYPE_VAL_ALTERNATE_HOST_ADDRESS);
+    public static final ICMPv4Type ICMPV4_TYPE_ECHO = new ICMPv4Type(ICMPV4_TYPE_VAL_ECHO);
+    public static final ICMPv4Type ICMPV4_TYPE_ROUTER_ADVERTISEMENT = new ICMPv4Type(ICMPV4_TYPE_VAL_ROUTER_ADVERTISEMENT);
+    public static final ICMPv4Type ICMPV4_TYPE_ROUTER_SOLICITATION  = new ICMPv4Type(ICMPV4_TYPE_VAL_ROUTER_SOLICITATION);
+    public static final ICMPv4Type ICMPV4_TYPE_TIME_EXCEEDED    = new ICMPv4Type(ICMPV4_TYPE_VAL_TIME_EXCEEDED);
+    public static final ICMPv4Type ICMPV4_TYPE_PARAMETER_PROBLEM    = new ICMPv4Type(ICMPV4_TYPE_VAL_PARAMETER_PROBLEM);
+    public static final ICMPv4Type ICMPV4_TYPE_TIMESTAMP    = new ICMPv4Type(ICMPV4_TYPE_VAL_TIMESTAMP);
+    public static final ICMPv4Type ICMPV4_TYPE_TIMESTAMP_REPLY  = new ICMPv4Type(ICMPV4_TYPE_VAL_TIMESTAMP_REPLY);
+    public static final ICMPv4Type ICMPV4_TYPE_INFORMATION_REQUEST  = new ICMPv4Type(ICMPV4_TYPE_VAL_INFORMATION_REQUEST);
+    public static final ICMPv4Type ICMPV4_TYPE_INFORMATION_REPLY    = new ICMPv4Type(ICMPV4_TYPE_VAL_INFORMATION_REPLY);
+    public static final ICMPv4Type ICMPV4_TYPE_ADDRESS_MASK_REQUEST = new ICMPv4Type(ICMPV4_TYPE_VAL_ADDRESS_MASK_REQUEST);
+    public static final ICMPv4Type ICMPV4_TYPE_ADDRESS_MASK_REPLY   = new ICMPv4Type(ICMPV4_TYPE_VAL_ADDRESS_MASK_REPLY);
+    public static final ICMPv4Type ICMPV4_TYPE_TRACEROUTE   = new ICMPv4Type(ICMPV4_TYPE_VAL_TRACEROUTE);
+    public static final ICMPv4Type ICMPV4_TYPE_DATAGRAM_CONVERSION_ERROR    = new ICMPv4Type(ICMPV4_TYPE_VAL_DATAGRAM_CONVERSION_ERROR);
+    public static final ICMPv4Type ICMPV4_TYPE_MOBILE_HOST_REDIRECT = new ICMPv4Type(ICMPV4_TYPE_VAL_MOBILE_HOST_REDIRECT);
+    public static final ICMPv4Type ICMPV4_TYPE_IPV6_WHERE_ARE_YOU  = new ICMPv4Type(ICMPV4_TYPE_VAL_IPV6_WHERE_ARE_YOU);
+    public static final ICMPv4Type ICMPV4_TYPE_IPV6_I_AM_HERE = new ICMPv4Type(ICMPV4_TYPE_VAL_IPV6_I_AM_HERE);
+    public static final ICMPv4Type ICMPV4_TYPE_MOBILE_REGISTRATION_REQUEST  = new ICMPv4Type(ICMPV4_TYPE_VAL_MOBILE_REGISTRATION_REQUEST);
+    public static final ICMPv4Type ICMPV4_TYPE_MOBILE_REGISTRATION_REPLY    = new ICMPv4Type(ICMPV4_TYPE_VAL_MOBILE_REGISTRATION_REPLY);
+    public static final ICMPv4Type ICMPV4_TYPE_DOMAIN_NAME_REQUEST  = new ICMPv4Type(ICMPV4_TYPE_VAL_DOMAIN_NAME_REQUEST);
+    public static final ICMPv4Type ICMPV4_TYPE_DOMAIN_NAME_REPLY    = new ICMPv4Type(ICMPV4_TYPE_VAL_DOMAIN_NAME_REPLY);
+    public static final ICMPv4Type ICMPV4_TYPE_SKIP = new ICMPv4Type(ICMPV4_TYPE_VAL_SKIP);
+    public static final ICMPv4Type ICMPV4_TYPE_PHOTURIS = new ICMPv4Type(ICMPV4_TYPE_VAL_PHOTURIS);
+    public static final ICMPv4Type ICMPV4_TYPE_EXPERIMENTAL_MOBILITY    = new ICMPv4Type(ICMPV4_TYPE_VAL_EXPERIMENTAL_MOBILITY);
+
+    private final short type;
+    
+    private static final int MIN_TYPE = 0;
+    private static final int MAX_TYPE = 0xFF;    
+
+    private ICMPv4Type(short type) {
+        this.type = type;
+    }
+
+    public static ICMPv4Type of(short type) {
+        if (type < MIN_TYPE || type > MAX_TYPE)
+            throw new IllegalArgumentException("Invalid ICMPv4 type: " + type);
+        switch (type) {
+            case ICMPV4_TYPE_VAL_ECHO_REPLY:
+                return ICMPV4_TYPE_ECHO_REPLY;
+            case ICMPV4_TYPE_VAL_DESTINATION_UNREACHABLE:
+                return ICMPV4_TYPE_DESTINATION_UNREACHABLE;
+            case ICMPV4_TYPE_VAL_SOURCE_QUENCH:
+                return ICMPV4_TYPE_SOURCE_QUENCH;
+            case ICMPV4_TYPE_VAL_REDIRECT:
+                return ICMPV4_TYPE_REDIRECT;
+            case ICMPV4_TYPE_VAL_ALTERNATE_HOST_ADDRESS:
+                return ICMPV4_TYPE_ALTERNATE_HOST_ADDRESS;
+            case ICMPV4_TYPE_VAL_ECHO:
+                return ICMPV4_TYPE_ECHO;
+            case ICMPV4_TYPE_VAL_ROUTER_ADVERTISEMENT:
+                return ICMPV4_TYPE_ROUTER_ADVERTISEMENT;
+            case ICMPV4_TYPE_VAL_ROUTER_SOLICITATION:
+                return ICMPV4_TYPE_ROUTER_SOLICITATION;
+            case ICMPV4_TYPE_VAL_TIME_EXCEEDED:
+                return ICMPV4_TYPE_TIME_EXCEEDED;
+            case ICMPV4_TYPE_VAL_PARAMETER_PROBLEM:
+                return ICMPV4_TYPE_PARAMETER_PROBLEM;
+            case ICMPV4_TYPE_VAL_TIMESTAMP:
+                return ICMPV4_TYPE_TIMESTAMP;
+            case ICMPV4_TYPE_VAL_TIMESTAMP_REPLY:
+                return ICMPV4_TYPE_TIMESTAMP_REPLY;
+            case ICMPV4_TYPE_VAL_INFORMATION_REQUEST:
+                return ICMPV4_TYPE_INFORMATION_REQUEST;
+            case ICMPV4_TYPE_VAL_INFORMATION_REPLY:
+                return ICMPV4_TYPE_INFORMATION_REPLY;
+            case ICMPV4_TYPE_VAL_ADDRESS_MASK_REQUEST:
+                return ICMPV4_TYPE_ADDRESS_MASK_REQUEST;
+            case ICMPV4_TYPE_VAL_ADDRESS_MASK_REPLY:
+                return ICMPV4_TYPE_ADDRESS_MASK_REPLY;
+            case ICMPV4_TYPE_VAL_TRACEROUTE:
+                return ICMPV4_TYPE_TRACEROUTE;
+            case ICMPV4_TYPE_VAL_DATAGRAM_CONVERSION_ERROR:
+                return ICMPV4_TYPE_DATAGRAM_CONVERSION_ERROR;
+            case ICMPV4_TYPE_VAL_MOBILE_HOST_REDIRECT:
+                return ICMPV4_TYPE_MOBILE_HOST_REDIRECT;
+            case ICMPV4_TYPE_VAL_IPV6_WHERE_ARE_YOU:
+                return ICMPV4_TYPE_IPV6_WHERE_ARE_YOU;
+            case ICMPV4_TYPE_VAL_IPV6_I_AM_HERE:
+                return ICMPV4_TYPE_IPV6_I_AM_HERE;
+            case ICMPV4_TYPE_VAL_MOBILE_REGISTRATION_REQUEST:
+                return ICMPV4_TYPE_MOBILE_REGISTRATION_REQUEST;
+            case ICMPV4_TYPE_VAL_MOBILE_REGISTRATION_REPLY:
+                return ICMPV4_TYPE_MOBILE_REGISTRATION_REPLY;
+            case ICMPV4_TYPE_VAL_DOMAIN_NAME_REQUEST:
+                return ICMPV4_TYPE_DOMAIN_NAME_REQUEST;
+            case ICMPV4_TYPE_VAL_DOMAIN_NAME_REPLY:
+                return ICMPV4_TYPE_DOMAIN_NAME_REPLY;
+            case ICMPV4_TYPE_VAL_SKIP:
+                return ICMPV4_TYPE_SKIP;
+            case ICMPV4_TYPE_VAL_PHOTURIS:
+                return ICMPV4_TYPE_PHOTURIS;
+            case ICMPV4_TYPE_VAL_EXPERIMENTAL_MOBILITY:
+                return ICMPV4_TYPE_EXPERIMENTAL_MOBILITY;
+            default:
+                return new ICMPv4Type(type);
+        }
+    }
+
+    @Override
+    public int getLength() {
+        return LENGTH;
+    }
+    
+    public short getType() {
+        return type;
+    }
+    
+    public void writeByte(ChannelBuffer c) {
+        c.writeByte(this.type);
+    }
+    
+    public static ICMPv4Type readByte(ChannelBuffer c) {
+        return ICMPv4Type.of(c.readUnsignedByte());
+    }
+
+}
diff --git a/java_gen/pre-written/src/main/java/org/openflow/types/IPv4.java b/java_gen/pre-written/src/main/java/org/openflow/types/IPv4.java
index c05a7e3..78b8dd2 100644
--- a/java_gen/pre-written/src/main/java/org/openflow/types/IPv4.java
+++ b/java_gen/pre-written/src/main/java/org/openflow/types/IPv4.java
@@ -1,7 +1,7 @@
 package org.openflow.types;
 
 import org.jboss.netty.buffer.ChannelBuffer;
-import org.openflow.exceptions.OFParseError;
+
 
 
 /**
@@ -56,61 +56,6 @@
         }
         return IPv4.of(raw);
     }
-    
-    public static OFValueType ofPossiblyMasked(final String string) {
-        int start = 0;
-        int shift = 24;
-        int slashPos;
-
-        String ip = string;
-        int maskBits = 0;
-        if ((slashPos = string.indexOf('/')) != -1) {
-            ip = string.substring(0, slashPos);
-            try {
-                String suffix = string.substring(slashPos + 1);
-                if (suffix.length() == 0)
-                    throw new IllegalArgumentException("IP Address not well formed: " + string);
-                maskBits = Integer.parseInt(suffix);
-            } catch (NumberFormatException e) {
-                throw new IllegalArgumentException("IP Address not well formed: " + string);
-            }
-            if (maskBits < 0 || maskBits > 32) {
-                throw new IllegalArgumentException("IP Address not well formed: " + string);
-            }
-        }
-        
-        int raw = 0;
-        while (shift >= 0) {
-            int end = ip.indexOf('.', start);
-            if (end == start || !((shift > 0) ^ (end < 0)))
-                throw new IllegalArgumentException("IP Address not well formed: " + string);
-
-            String substr =
-                    end > 0 ? ip.substring(start, end) : ip.substring(start);
-            int val;
-            try {
-                val = Integer.parseInt(substr);
-            } catch (NumberFormatException e) {
-                throw new IllegalArgumentException("IP Address not well formed: " + string);
-            }
-            if (val < 0 || val > 255)
-                throw new IllegalArgumentException("IP Address not well formed: " + string);
-
-            raw |= val << shift;
-
-            shift -= 8;
-            start = end + 1;
-        }
-        
-        if (maskBits == 0) {
-            // No mask
-            return IPv4.of(raw);
-        } else {
-            // With mask
-            int mask = (-1) << (32 - maskBits);
-            return Masked.<IPv4>of(IPv4.of(raw), IPv4.of(mask));
-        }
-    }
 
     public int getInt() {
         return rawValue;
@@ -170,22 +115,12 @@
         return true;
     }
     
-    public static final Serializer<IPv4> SERIALIZER_V10 = new SerializerV10();
-    public static final Serializer<IPv4> SERIALIZER_V11 = SERIALIZER_V10;
-    public static final Serializer<IPv4> SERIALIZER_V12 = SERIALIZER_V10;
-    public static final Serializer<IPv4> SERIALIZER_V13 = SERIALIZER_V10;
-    
-    private static class SerializerV10 implements OFValueType.Serializer<IPv4> {
-
-        @Override
-        public void writeTo(IPv4 value, ChannelBuffer c) {
-            c.writeInt(value.rawValue);
-        }
-
-        @Override
-        public IPv4 readFrom(ChannelBuffer c) throws OFParseError {
-            return IPv4.of(c.readInt());
-        }
-        
+    public void write4Bytes(ChannelBuffer c) {
+        c.writeInt(rawValue);
     }
+    
+    public static IPv4 read4Bytes(ChannelBuffer c) {
+        return IPv4.of(c.readInt());
+    }
+    
 }
diff --git a/java_gen/pre-written/src/main/java/org/openflow/types/IPv4WithMask.java b/java_gen/pre-written/src/main/java/org/openflow/types/IPv4WithMask.java
new file mode 100644
index 0000000..afb89ed
--- /dev/null
+++ b/java_gen/pre-written/src/main/java/org/openflow/types/IPv4WithMask.java
@@ -0,0 +1,83 @@
+package org.openflow.types;
+
+public class IPv4WithMask extends Masked<IPv4> {
+
+    private IPv4WithMask(int rawValue, int rawMask) {
+        super(IPv4.of(rawValue), IPv4.of(rawMask));
+    }
+    
+    private IPv4WithMask(IPv4 value, IPv4 mask) {
+        super(value, mask);
+    }
+    
+    public static IPv4WithMask of(int rawValue, int rawMask) {
+        return new IPv4WithMask(rawValue, rawMask);
+    }
+    
+    public static IPv4WithMask of(IPv4 value, IPv4 mask) {
+        return new IPv4WithMask(value, mask);
+    }
+    
+    @Override
+    public String toString() {
+        StringBuilder res = new StringBuilder();
+        res.append(((IPv4)value).toString());
+        
+        int maskint = ((IPv4)mask).getInt();
+        res.append('/');
+        if (Integer.bitCount((~maskint) + 1) == 1) {
+            // CIDR notation
+            res.append(Integer.bitCount(maskint));
+        } else {
+            // Full address mask
+            res.append(((IPv4)mask).toString());
+        }
+        
+        return res.toString();
+    }
+    
+    public static OFValueType ofPossiblyMasked(final String string) {
+        int slashPos;
+        String ip = string;
+        int maskBits = 0;
+        IPv4 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("IP Address not well formed: " + string);
+                if (suffix.indexOf('.') != -1) {
+                    // Full mask
+                    maskAddress = IPv4.of(suffix);
+                } else {
+                    // CIDR Suffix
+                    maskBits = Integer.parseInt(suffix);
+                }
+            } catch (NumberFormatException e) {
+                throw new IllegalArgumentException("IP Address not well formed: " + string);
+            }
+            if (maskBits < 0 || maskBits > 32) {
+                throw new IllegalArgumentException("IP Address not well formed: " + string);
+            }
+        }
+        
+        // Read IP
+        IPv4 ipv4 = IPv4.of(ip);
+        
+        if (maskAddress != null) {
+            // Full address mask
+            return IPv4WithMask.of(ipv4, maskAddress);
+        } else if (maskBits == 0) {
+            // No mask
+            return ipv4;
+        } else {
+            // With mask
+            int mask = (-1) << (32 - maskBits);
+            return IPv4WithMask.of(ipv4, IPv4.of(mask));
+        }
+    }
+
+}
diff --git a/java_gen/pre-written/src/main/java/org/openflow/types/IPv6.java b/java_gen/pre-written/src/main/java/org/openflow/types/IPv6.java
index ff5e9ed..e3166fd 100644
--- a/java_gen/pre-written/src/main/java/org/openflow/types/IPv6.java
+++ b/java_gen/pre-written/src/main/java/org/openflow/types/IPv6.java
@@ -270,24 +270,12 @@
         return true;
     }
     
-    public static final Serializer<IPv6> SERIALIZER_V12 = new SerializerV12();
-    public static final Serializer<IPv6> SERIALIZER_V13 = SERIALIZER_V12;
-    
-    private static class SerializerV12 implements OFValueType.Serializer<IPv6> {
-
-        @Override
-        public void writeTo(IPv6 value, ChannelBuffer c) {
-            c.writeLong(value.raw1);
-            c.writeLong(value.raw2);            
-        }
-
-        @Override
-        public IPv6 readFrom(ChannelBuffer c) throws OFParseError {
-            return IPv6.of(c.readLong(), c.readLong());
-        }
-        
+    public void write16Bytes(ChannelBuffer c) {
+        c.writeLong(this.raw1);
+        c.writeLong(this.raw2);            
     }
-    
-    
 
+    public static IPv6 read16Bytes(ChannelBuffer c) throws OFParseError {
+        return IPv6.of(c.readLong(), c.readLong());
+    }
 }
diff --git a/java_gen/pre-written/src/main/java/org/openflow/types/IPv6FlowLabel.java b/java_gen/pre-written/src/main/java/org/openflow/types/IPv6FlowLabel.java
new file mode 100644
index 0000000..6d9bfb5
--- /dev/null
+++ b/java_gen/pre-written/src/main/java/org/openflow/types/IPv6FlowLabel.java
@@ -0,0 +1,56 @@
+package org.openflow.types;
+
+import org.jboss.netty.buffer.ChannelBuffer;
+import org.openflow.exceptions.OFParseError;
+
+public class IPv6FlowLabel implements OFValueType {
+
+    static final int LENGTH = 4;
+    
+    private final int label;
+    
+    private IPv6FlowLabel(int label) {
+        this.label = label;
+    }
+    
+    public static IPv6FlowLabel of(int label) {
+        return new IPv6FlowLabel(label);
+    }
+
+    @Override
+    public int getLength() {
+        return LENGTH;
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (!(obj instanceof IPv6FlowLabel))
+            return false;
+        IPv6FlowLabel other = (IPv6FlowLabel)obj;
+        if (other.label != this.label)
+            return false;
+        return true;
+    }
+
+    @Override
+    public int hashCode() {
+        final int prime = 59;
+        int result = 1;
+        result = prime * result + label;
+        return result;
+    }
+
+    @Override
+    public String toString() {
+        return Integer.toHexString(label);
+    }
+
+    public void write4Bytes(ChannelBuffer c) {
+        c.writeInt(this.label);
+    }
+
+    public static IPv6FlowLabel read4Bytes(ChannelBuffer c) throws OFParseError {
+        return IPv6FlowLabel.of((int)(c.readUnsignedInt() & 0xFFFFFFFF));
+    }
+
+}
diff --git a/java_gen/pre-written/src/main/java/org/openflow/types/IPv6WithMask.java b/java_gen/pre-written/src/main/java/org/openflow/types/IPv6WithMask.java
new file mode 100644
index 0000000..f809d67
--- /dev/null
+++ b/java_gen/pre-written/src/main/java/org/openflow/types/IPv6WithMask.java
@@ -0,0 +1,91 @@
+package org.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 OFValueType ofPossiblyMasked(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 ipv6;
+        } 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));
+        }
+    }
+
+
+}
diff --git a/java_gen/pre-written/src/main/java/org/openflow/types/IpDscp.java b/java_gen/pre-written/src/main/java/org/openflow/types/IpDscp.java
new file mode 100644
index 0000000..033e574
--- /dev/null
+++ b/java_gen/pre-written/src/main/java/org/openflow/types/IpDscp.java
@@ -0,0 +1,233 @@
+package org.openflow.types;
+
+import org.jboss.netty.buffer.ChannelBuffer;
+import org.openflow.exceptions.OFParseError;
+
+public enum IpDscp implements OFValueType {
+    DSCP_0((byte)0),
+    DSCP_1((byte)1),
+    DSCP_2((byte)2),
+    DSCP_3((byte)3),
+    DSCP_4((byte)4),
+    DSCP_5((byte)5),
+    DSCP_6((byte)6),
+    DSCP_7((byte)7),
+    DSCP_8((byte)8),
+    DSCP_9((byte)9),
+    DSCP_10((byte)10),
+    DSCP_11((byte)11),
+    DSCP_12((byte)12),
+    DSCP_13((byte)13),
+    DSCP_14((byte)14),
+    DSCP_15((byte)15),
+    DSCP_16((byte)16),
+    DSCP_17((byte)17),
+    DSCP_18((byte)18),
+    DSCP_19((byte)19),
+    DSCP_20((byte)20),
+    DSCP_21((byte)21),
+    DSCP_22((byte)22),
+    DSCP_23((byte)23),
+    DSCP_24((byte)24),
+    DSCP_25((byte)25),
+    DSCP_26((byte)26),
+    DSCP_27((byte)27),
+    DSCP_28((byte)28),
+    DSCP_29((byte)29),
+    DSCP_30((byte)30),
+    DSCP_31((byte)31),
+    DSCP_32((byte)32),
+    DSCP_33((byte)33),
+    DSCP_34((byte)34),
+    DSCP_35((byte)35),
+    DSCP_36((byte)36),
+    DSCP_37((byte)37),
+    DSCP_38((byte)38),
+    DSCP_39((byte)39),
+    DSCP_40((byte)40),
+    DSCP_41((byte)41),
+    DSCP_42((byte)42),
+    DSCP_43((byte)43),
+    DSCP_44((byte)44),
+    DSCP_45((byte)45),
+    DSCP_46((byte)46),
+    DSCP_47((byte)47),
+    DSCP_48((byte)48),
+    DSCP_49((byte)49),
+    DSCP_50((byte)50),
+    DSCP_51((byte)51),
+    DSCP_52((byte)52),
+    DSCP_53((byte)53),
+    DSCP_54((byte)54),
+    DSCP_55((byte)55),
+    DSCP_56((byte)56),
+    DSCP_57((byte)57),
+    DSCP_58((byte)58),
+    DSCP_59((byte)59),
+    DSCP_60((byte)60),
+    DSCP_61((byte)61),
+    DSCP_62((byte)62),
+    DSCP_63((byte)63);
+    
+    static final int LENGTH = 1;
+    
+    private final byte dscp;
+    
+    private IpDscp(byte dscp) {
+        this.dscp = dscp;
+    }
+    
+    public static IpDscp of(byte dscp) {
+        switch (dscp) {
+            case 0:
+                return DSCP_0;
+            case 1:
+                return DSCP_1;
+            case 2:
+                return DSCP_2;
+            case 3:
+                return DSCP_3;
+            case 4:
+                return DSCP_4;
+            case 5:
+                return DSCP_5;
+            case 6:
+                return DSCP_6;
+            case 7:
+                return DSCP_7;
+            case 8:
+                return DSCP_8;
+            case 9:
+                return DSCP_9;
+            case 10:
+                return DSCP_10;
+            case 11:
+                return DSCP_11;
+            case 12:
+                return DSCP_12;
+            case 13:
+                return DSCP_13;
+            case 14:
+                return DSCP_14;
+            case 15:
+                return DSCP_15;
+            case 16:
+                return DSCP_16;
+            case 17:
+                return DSCP_17;
+            case 18:
+                return DSCP_18;
+            case 19:
+                return DSCP_19;
+            case 20:
+                return DSCP_20;
+            case 21:
+                return DSCP_21;
+            case 22:
+                return DSCP_22;
+            case 23:
+                return DSCP_23;
+            case 24:
+                return DSCP_24;
+            case 25:
+                return DSCP_25;
+            case 26:
+                return DSCP_26;
+            case 27:
+                return DSCP_27;
+            case 28:
+                return DSCP_28;
+            case 29:
+                return DSCP_29;
+            case 30:
+                return DSCP_30;
+            case 31:
+                return DSCP_31;
+            case 32:
+                return DSCP_32;
+            case 33:
+                return DSCP_33;
+            case 34:
+                return DSCP_34;
+            case 35:
+                return DSCP_35;
+            case 36:
+                return DSCP_36;
+            case 37:
+                return DSCP_37;
+            case 38:
+                return DSCP_38;
+            case 39:
+                return DSCP_39;
+            case 40:
+                return DSCP_40;
+            case 41:
+                return DSCP_41;
+            case 42:
+                return DSCP_42;
+            case 43:
+                return DSCP_43;
+            case 44:
+                return DSCP_44;
+            case 45:
+                return DSCP_45;
+            case 46:
+                return DSCP_46;
+            case 47:
+                return DSCP_47;
+            case 48:
+                return DSCP_48;
+            case 49:
+                return DSCP_49;
+            case 50:
+                return DSCP_50;
+            case 51:
+                return DSCP_51;
+            case 52:
+                return DSCP_52;
+            case 53:
+                return DSCP_53;
+            case 54:
+                return DSCP_54;
+            case 55:
+                return DSCP_55;
+            case 56:
+                return DSCP_56;
+            case 57:
+                return DSCP_57;
+            case 58:
+                return DSCP_58;
+            case 59:
+                return DSCP_59;
+            case 60:
+                return DSCP_60;
+            case 61:
+                return DSCP_61;
+            case 62:
+                return DSCP_62;
+            case 63:
+                return DSCP_63;
+            default:
+                throw new IllegalArgumentException("Illegal IPv4 DSCP value: " + dscp);
+        }
+    }
+
+    @Override
+    public int getLength() {
+        return LENGTH;
+    }
+
+    @Override
+    public String toString() {
+        return Integer.toHexString(dscp);
+    }
+
+    public void writeByte(ChannelBuffer c) {
+        c.writeByte(this.dscp);
+    }
+
+    public static IpDscp readByte(ChannelBuffer c) throws OFParseError {
+        return IpDscp.of((byte)(c.readUnsignedByte()));
+    }
+
+}
diff --git a/java_gen/pre-written/src/main/java/org/openflow/types/IpEcn.java b/java_gen/pre-written/src/main/java/org/openflow/types/IpEcn.java
new file mode 100644
index 0000000..b261d41
--- /dev/null
+++ b/java_gen/pre-written/src/main/java/org/openflow/types/IpEcn.java
@@ -0,0 +1,53 @@
+package org.openflow.types;
+
+import org.jboss.netty.buffer.ChannelBuffer;
+import org.openflow.exceptions.OFParseError;
+
+public enum IpEcn implements OFValueType {
+    ECN_00((byte)0),
+    ECN_01((byte)1),
+    ECN_10((byte)2),
+    ECN_11((byte)3);
+    
+    static final int LENGTH = 1;
+    
+    private final byte ecn;
+    
+    private IpEcn(byte ecn) {
+        this.ecn = ecn;
+    }
+    
+    public static IpEcn of(byte ecn) {
+        switch (ecn) {
+            case 0:
+                return ECN_00;
+            case 1:
+                return ECN_01;
+            case 2:
+                return ECN_10;
+            case 3:
+                return ECN_11;
+            default:
+                throw new IllegalArgumentException("Illegal IP ECN value: " + ecn);
+        }
+    }
+
+    @Override
+    public int getLength() {
+        return LENGTH;
+    }
+
+    @Override
+    public String toString() {
+        return (ecn < 3 ? "0" : "") + Integer.toBinaryString(ecn);
+    }
+
+    public void writeByte(ChannelBuffer c) {
+        c.writeByte(this.ecn);
+    }
+
+    public static IpEcn readByte(ChannelBuffer c) throws OFParseError {
+        return IpEcn.of((byte)(c.readUnsignedByte()));
+    }
+
+}
diff --git a/java_gen/pre-written/src/main/java/org/openflow/types/IpProtocol.java b/java_gen/pre-written/src/main/java/org/openflow/types/IpProtocol.java
index fc28370..436db1d 100644
--- a/java_gen/pre-written/src/main/java/org/openflow/types/IpProtocol.java
+++ b/java_gen/pre-written/src/main/java/org/openflow/types/IpProtocol.java
@@ -1,7 +1,6 @@
 package org.openflow.types;
 
 import org.jboss.netty.buffer.ChannelBuffer;
-import org.openflow.exceptions.OFParseError;
 
 /**
  * IP-Protocol field representation
@@ -309,20 +308,6 @@
         return LENGTH;
     }
 
-    volatile byte[] bytesCache = null;
-
-    @Override
-    public byte[] getBytes() {
-        if (bytesCache == null) {
-            synchronized (this) {
-                if (bytesCache == null) {
-                    bytesCache = new byte[] { (byte)proto };
-                }
-            }
-        }
-        return bytesCache;
-    }
-
     public static IpProtocol of(short proto) {
         switch (proto) {
             case IP_PROTO_NUM_HOPOPT:
@@ -639,24 +624,12 @@
     public String toString() {
         return Integer.toHexString(proto);
     }
-
-    public static final Serializer<IpProtocol> SERIALIZER_V10 = new SerializerV10();
-    public static final Serializer<IpProtocol> SERIALIZER_V11 = SERIALIZER_V10;
-    public static final Serializer<IpProtocol> SERIALIZER_V12 = SERIALIZER_V10;
-    public static final Serializer<IpProtocol> SERIALIZER_V13 = SERIALIZER_V10;
-
-    private static class SerializerV10 implements OFValueType.Serializer<IpProtocol> {
-
-        @Override
-        public void writeTo(IpProtocol value, ChannelBuffer c) {
-            c.writeByte(value.proto);
-        }
-
-        @Override
-        public IpProtocol readFrom(ChannelBuffer c) throws OFParseError {
-            return IpProtocol.of((short)(c.readUnsignedByte() & 0x00FF));
-        }
-
+    
+    public void writeByte(ChannelBuffer c) {
+        c.writeByte(this.proto);
     }
 
+    public static IpProtocol readByte(ChannelBuffer c) {
+        return IpProtocol.of(c.readUnsignedByte());
+    }
 }
diff --git a/java_gen/pre-written/src/main/java/org/openflow/types/MacAddress.java b/java_gen/pre-written/src/main/java/org/openflow/types/MacAddress.java
index ec15f74..a18dff3 100644
--- a/java_gen/pre-written/src/main/java/org/openflow/types/MacAddress.java
+++ b/java_gen/pre-written/src/main/java/org/openflow/types/MacAddress.java
@@ -107,28 +107,15 @@
         return rawValue;
     }
 
-    public static final Serializer<MacAddress> SERIALIZER_V10 = new SerializerV10();
-    public static final Serializer<MacAddress> SERIALIZER_V11 = SERIALIZER_V10;
-    public static final Serializer<MacAddress> SERIALIZER_V12 = SERIALIZER_V10;
-    public static final Serializer<MacAddress> SERIALIZER_V13 = SERIALIZER_V10;
-
-    private static class SerializerV10 implements OFValueType.Serializer<MacAddress> {
-
-        @Override
-        public void writeTo(MacAddress value, ChannelBuffer c) {
-            c.writeInt((int) (value.rawValue >> 16));
-            c.writeShort((int) value.rawValue & 0xFFFF);
-        }
-
-        @Override
-        public MacAddress readFrom(ChannelBuffer c) throws OFParseError {
-            long raw = c.readUnsignedInt() << 16 | c.readUnsignedShort();
-            return MacAddress.of(raw);
-        }
-        
-        
+    public void write6Bytes(ChannelBuffer c) {
+        c.writeInt((int) (this.rawValue >> 16));
+        c.writeShort((int) this.rawValue & 0xFFFF);
     }
 
+    public static MacAddress read6Bytes(ChannelBuffer c) throws OFParseError {
+        long raw = c.readUnsignedInt() << 16 | c.readUnsignedShort();
+        return MacAddress.of(raw);
+    }
     
     
 
diff --git a/java_gen/pre-written/src/main/java/org/openflow/types/Masked.java b/java_gen/pre-written/src/main/java/org/openflow/types/Masked.java
index de6b604..011bae8 100644
--- a/java_gen/pre-written/src/main/java/org/openflow/types/Masked.java
+++ b/java_gen/pre-written/src/main/java/org/openflow/types/Masked.java
@@ -3,10 +3,10 @@
 
 
 public class Masked<T extends OFValueType> implements OFValueType {
-    private T value;
-    private T mask;
+    protected T value;
+    protected T mask;
     
-    private Masked(T value, T mask) {
+    protected Masked(T value, T mask) {
         this.value = value;
         this.mask = mask;
     }
@@ -23,28 +23,6 @@
     public int getLength() {
         return this.value.getLength() + this.mask.getLength();
     }
-
-    volatile byte[] bytesCache = null;
-    
-    @Override
-    public byte[] getBytes() {
-        if (bytesCache == null) {
-            synchronized(this) {
-                if (bytesCache == null) {
-                    byte[] bytesValue = this.value.getBytes();
-                    byte[] bytesMask = this.mask.getBytes();
-                    bytesCache = new byte[bytesValue.length + bytesMask.length];
-                    System.arraycopy(bytesValue, 0, bytesCache, 0, bytesValue.length);
-                    System.arraycopy(bytesMask, 0, bytesCache, bytesValue.length, bytesMask.length);
-                }
-            }
-        }
-        return bytesCache;
-    }
-
-    public static <T extends OFValueType> Masked<T> of(T value, T mask) {
-        return new Masked<T>(value, mask);
-    }
         
     @Override
     public boolean equals(Object obj) {
@@ -65,33 +43,10 @@
 
     @Override
     public String toString() {
-        if (value.getClass() == IPv4.class) {
-            // TODO: How to output the mask when not in CIDR notation?
-            StringBuilder res = new StringBuilder();
-            res.append(((IPv4)value).toString());
-            
-            int maskint = ((IPv4)mask).getInt();
-            if (Integer.bitCount((~maskint) + 1) == 1) {
-                // CIDR notation
-                res.append('/');
-                res.append(Integer.bitCount(maskint));
-            } else {
-                // Arbitrary mask not in CIDR notation
-                // TODO: HERE?
-            }
-            
-            return res.toString();
-        } else if (value.getClass() == IPv6.class) {
-            // TODO: Return IPv6 string
-            StringBuilder sb = new StringBuilder();
-            sb.append(value.toString()).append('/').append(mask.toString());
-            return sb.toString();
-        } else {
-            // General representation: value/mask
-            StringBuilder sb = new StringBuilder();
-            sb.append(value.toString()).append('/').append(mask.toString());
-            return sb.toString();
-        }
+        // General representation: value/mask
+        StringBuilder sb = new StringBuilder();
+        sb.append(value.toString()).append('/').append(mask.toString());
+        return sb.toString();
     }
     
 }
diff --git a/java_gen/pre-written/src/main/java/org/openflow/types/OFPhysicalPort.java b/java_gen/pre-written/src/main/java/org/openflow/types/OFPhysicalPort.java
index 9d87b8f..d8f71a3 100644
--- a/java_gen/pre-written/src/main/java/org/openflow/types/OFPhysicalPort.java
+++ b/java_gen/pre-written/src/main/java/org/openflow/types/OFPhysicalPort.java
@@ -28,23 +28,6 @@
     public int getLength() {
         return LENGTH;
     }
-    
-    volatile byte[] bytesCache;
-    
-    @Override
-    public byte[] getBytes() {
-        if (bytesCache == null) {
-            synchronized (this) {
-                if (bytesCache == null) {
-                    bytesCache = new byte[] { (byte)(port & 0xFF),
-                                              (byte)((port >>> 8) & 0xFF),
-                                              (byte)((port >>> 16) & 0xFF),
-                                              (byte)((port >>> 24) & 0xFF)};
-                }
-            }
-        }
-        return bytesCache;
-    }
 
     @Override
     public boolean equals(Object obj) {
@@ -69,22 +52,12 @@
         return Integer.toHexString(port);
     }
 
-    public static final Serializer<OFPhysicalPort> SERIALIZER_V11 = new SerializerV11();
-    public static final Serializer<OFPhysicalPort> SERIALIZER_V12 = SERIALIZER_V11;
-    public static final Serializer<OFPhysicalPort> SERIALIZER_V13 = SERIALIZER_V11;
+    public void write4Bytes(ChannelBuffer c) {
+        c.writeInt(this.port);
+    }
 
-    private static class SerializerV11 implements OFValueType.Serializer<OFPhysicalPort> {
-
-        @Override
-        public void writeTo(OFPhysicalPort value, ChannelBuffer c) {
-            c.writeInt(value.port);
-        }
-
-        @Override
-        public OFPhysicalPort readFrom(ChannelBuffer c) throws OFParseError {
-            return OFPhysicalPort.of((int)(c.readUnsignedInt() & 0xFFFFFFFF));
-        }
-
+    public static OFPhysicalPort read4Bytes(ChannelBuffer c) throws OFParseError {
+        return OFPhysicalPort.of((int)(c.readUnsignedInt() & 0xFFFFFFFF));
     }
 
 }
diff --git a/java_gen/pre-written/src/main/java/org/openflow/types/OFPort.java b/java_gen/pre-written/src/main/java/org/openflow/types/OFPort.java
index 22b347d..3272660 100644
--- a/java_gen/pre-written/src/main/java/org/openflow/types/OFPort.java
+++ b/java_gen/pre-written/src/main/java/org/openflow/types/OFPort.java
@@ -497,23 +497,6 @@
         return LENGTH;
     }
     
-    volatile byte[] bytesCache;
-    
-    @Override
-    public byte[] getBytes() {
-        if (bytesCache == null) {
-            synchronized (this) {
-                if (bytesCache == null) {
-                    bytesCache = new byte[] { (byte)(portNumber & 0xFF),
-                                              (byte)((portNumber >>> 8) & 0xFF),
-                                              (byte)((portNumber >>> 16) & 0xFF),
-                                              (byte)((portNumber >>> 24) & 0xFF) };
-                }
-            }
-        }
-        return bytesCache;
-    }
-
     @Override
     public boolean equals(Object obj) {
         if (!(obj instanceof OFPort))
@@ -532,36 +515,19 @@
         return result;
     }
 
-    public static final Serializer<OFPort> SERIALIZER_V10 = new SerializerV10();
-    public static final Serializer<OFPort> SERIALIZER_V11 = new SerializerV11();
-    public static final Serializer<OFPort> SERIALIZER_V12 = SERIALIZER_V11;
-    public static final Serializer<OFPort> SERIALIZER_V13 = SERIALIZER_V11;
-
-    private static class SerializerV10 implements OFValueType.Serializer<OFPort> {
-
-        @Override
-        public void writeTo(OFPort value, ChannelBuffer c) {
-            c.writeShort(value.portNumber);
-        }
-
-        @Override
-        public OFPort readFrom(ChannelBuffer c) throws OFParseError {
-            return OFPort.of((c.readUnsignedShort() & 0x0FFFF));
-        }
-
+    public void write2Bytes(ChannelBuffer c) {
+        c.writeShort(this.portNumber);
     }
 
-    private static class SerializerV11 implements OFValueType.Serializer<OFPort> {
+    public static OFPort read2Bytes(ChannelBuffer c) throws OFParseError {
+        return OFPort.of((c.readUnsignedShort() & 0x0FFFF));
+    }
 
-        @Override
-        public void writeTo(OFPort value, ChannelBuffer c) {
-            c.writeInt(value.portNumber);
-        }
+    public void write4Bytes(ChannelBuffer c) {
+        c.writeInt(this.portNumber);
+    }
 
-        @Override
-        public OFPort readFrom(ChannelBuffer c) throws OFParseError {
-            return OFPort.of((int)(c.readUnsignedInt() & 0xFFFFFFFF));
-        }
-
+    public static OFPort read4Bytes(ChannelBuffer c) throws OFParseError {
+        return OFPort.of((int)(c.readUnsignedInt() & 0xFFFFFFFF));
     }
 }
diff --git a/java_gen/pre-written/src/main/java/org/openflow/types/OFValueType.java b/java_gen/pre-written/src/main/java/org/openflow/types/OFValueType.java
index 01e7012..51c8b36 100644
--- a/java_gen/pre-written/src/main/java/org/openflow/types/OFValueType.java
+++ b/java_gen/pre-written/src/main/java/org/openflow/types/OFValueType.java
@@ -1,18 +1,10 @@
 package org.openflow.types;
 
-import org.jboss.netty.buffer.ChannelBuffer;
-import org.openflow.exceptions.OFParseError;
 
 
 
 public interface OFValueType {
 
     public int getLength();
-    public byte[] getBytes();
-    
-    public interface Serializer<T extends OFValueType> {
-        public void writeTo(T value, ChannelBuffer c);
-        public T readFrom(ChannelBuffer c) throws OFParseError; 
-    }
-    
+
 }
diff --git a/java_gen/pre-written/src/main/java/org/openflow/types/TransportPort.java b/java_gen/pre-written/src/main/java/org/openflow/types/TransportPort.java
index 86ed53e..cecb349 100644
--- a/java_gen/pre-written/src/main/java/org/openflow/types/TransportPort.java
+++ b/java_gen/pre-written/src/main/java/org/openflow/types/TransportPort.java
@@ -31,21 +31,6 @@
     public int getLength() {
         return LENGTH;
     }
-    
-    volatile byte[] bytesCache;
-    
-    @Override
-    public byte[] getBytes() {
-        if (bytesCache == null) {
-            synchronized (this) {
-                if (bytesCache == null) {
-                    bytesCache = new byte[] { (byte)(port & 0xFF),
-                                              (byte)((port >>> 8) & 0xFF)};
-                }
-            }
-        }
-        return bytesCache;
-    }
 
     @Override
     public boolean equals(Object obj) {
@@ -70,23 +55,12 @@
         return Integer.toString(port);
     }
 
-    public static final Serializer<TransportPort> SERIALIZER_V10 = new SerializerV10();
-    public static final Serializer<TransportPort> SERIALIZER_V11 = SERIALIZER_V10;
-    public static final Serializer<TransportPort> SERIALIZER_V12 = SERIALIZER_V10;
-    public static final Serializer<TransportPort> SERIALIZER_V13 = SERIALIZER_V10;
+    public void write2Bytes(ChannelBuffer c) {
+        c.writeShort(this.port);
+    }
 
-    private static class SerializerV10 implements OFValueType.Serializer<TransportPort> {
-
-        @Override
-        public void writeTo(TransportPort value, ChannelBuffer c) {
-            c.writeShort(value.port);
-        }
-
-        @Override
-        public TransportPort readFrom(ChannelBuffer c) throws OFParseError {
-            return TransportPort.of((c.readUnsignedShort() & 0x0FFFF));
-        }
-
+    public static TransportPort read2Bytes(ChannelBuffer c) throws OFParseError {
+        return TransportPort.of((c.readUnsignedShort() & 0x0FFFF));
     }
 
 }
diff --git a/java_gen/pre-written/src/main/java/org/openflow/types/VlanPcp.java b/java_gen/pre-written/src/main/java/org/openflow/types/VlanPcp.java
index 0a7b7c5..2f406c8 100644
--- a/java_gen/pre-written/src/main/java/org/openflow/types/VlanPcp.java
+++ b/java_gen/pre-written/src/main/java/org/openflow/types/VlanPcp.java
@@ -49,38 +49,13 @@
     public int getLength() {
         return LENGTH;
     }
-
-    volatile byte[] bytesCache = null;
-
-    public byte[] getBytes() {
-        if (bytesCache == null) {
-            synchronized (this) {
-                if (bytesCache == null) {
-                    bytesCache =
-                            new byte[] { pcp };
-                }
-            }
-        }
-        return bytesCache;
+    
+    public void writeByte(ChannelBuffer c) {
+        c.writeShort(this.pcp);
     }
-    
-    public static final Serializer<VlanPcp> SERIALIZER_V10 = new SerializerV10();
-    public static final Serializer<VlanPcp> SERIALIZER_V11 = SERIALIZER_V10;
-    public static final Serializer<VlanPcp> SERIALIZER_V12 = SERIALIZER_V10;
-    public static final Serializer<VlanPcp> SERIALIZER_V13 = SERIALIZER_V10;
-    
-    private static class SerializerV10 implements OFValueType.Serializer<VlanPcp> {
 
-        @Override
-        public void writeTo(VlanPcp value, ChannelBuffer c) {
-            c.writeShort(value.pcp);
-        }
-
-        @Override
-        public VlanPcp readFrom(ChannelBuffer c) throws OFParseError {
-            return VlanPcp.of((byte)(c.readUnsignedByte() & 0xFF));
-        }
-        
+    public static VlanPcp readByte(ChannelBuffer c) throws OFParseError {
+        return VlanPcp.of((byte)(c.readUnsignedByte() & 0xFF));
     }
     
 }
diff --git a/java_gen/pre-written/src/main/java/org/openflow/types/VlanVid.java b/java_gen/pre-written/src/main/java/org/openflow/types/VlanVid.java
index 11c733d..a2b38b2 100644
--- a/java_gen/pre-written/src/main/java/org/openflow/types/VlanVid.java
+++ b/java_gen/pre-written/src/main/java/org/openflow/types/VlanVid.java
@@ -66,23 +66,12 @@
         return bytesCache;
     }
     
-    public static final Serializer<VlanVid> SERIALIZER_V10 = new SerializerV10();
-    public static final Serializer<VlanVid> SERIALIZER_V11 = SERIALIZER_V10;
-    public static final Serializer<VlanVid> SERIALIZER_V12 = SERIALIZER_V10;
-    public static final Serializer<VlanVid> SERIALIZER_V13 = SERIALIZER_V10;
-    
-    private static class SerializerV10 implements OFValueType.Serializer<VlanVid> {
+    public void write2Bytes(ChannelBuffer c) {
+        c.writeShort(this.vid);
+    }
 
-        @Override
-        public void writeTo(VlanVid value, ChannelBuffer c) {
-            c.writeShort(value.vid);
-        }
-
-        @Override
-        public VlanVid readFrom(ChannelBuffer c) throws OFParseError {
-            return VlanVid.of(c.readShort());
-        }
-        
+    public VlanVid read2Bytes(ChannelBuffer c) throws OFParseError {
+        return VlanVid.of(c.readShort());
     }
     
 }
diff --git a/java_gen/pre-written/src/test/java/org/openflow/types/IPv4Test.java b/java_gen/pre-written/src/test/java/org/openflow/types/IPv4Test.java
index 8a8c3e0..d344021 100644
--- a/java_gen/pre-written/src/test/java/org/openflow/types/IPv4Test.java
+++ b/java_gen/pre-written/src/test/java/org/openflow/types/IPv4Test.java
@@ -42,6 +42,27 @@
             "1.x.3.4",
             "1.2x.3.4"
     };
+    
+    String[] ipsWithMask = {
+                            "1.2.3.4/24",
+                            "192.168.130.140/255.255.192.0",
+                            "127.0.0.1/8",
+                            "8.8.8.8",
+    };
+    
+    boolean[] hasMask = {
+                         true,
+                         true,
+                         true,
+                         false
+    };
+    
+    byte[][][] ipsWithMaskValues = {
+                             new byte[][] { new byte[] { (byte)0x01, (byte)0x02, (byte)0x03, (byte)0x04 }, new byte[] { (byte)0xFF, (byte)0xFF, (byte)0xFF, (byte)0x00 } },
+                             new byte[][] { new byte[] { (byte)0xC0, (byte)0xA8, (byte)0x82, (byte)0x8C }, new byte[] { (byte)0xFF, (byte)0xFF, (byte)0xC0, (byte)0x00 } },
+                             new byte[][] { new byte[] { (byte)0x7F, (byte)0x00, (byte)0x00, (byte)0x01 }, new byte[] { (byte)0xFF, (byte)0x00, (byte)0x00, (byte)0x00 } },
+                             new byte[][] { new byte[] { (byte)0x08, (byte)0x08, (byte)0x08, (byte)0x08 }, null }
+    };
 
 
     @Test
@@ -67,7 +88,7 @@
     @Test
     public void testReadFrom() throws OFParseError, OFShortRead {
         for(int i=0; i < testAddresses.length; i++ ) {
-            IPv4 ip = IPv4.SERIALIZER_V10.readFrom(ChannelBuffers.copiedBuffer(testAddresses[i]));
+            IPv4 ip = IPv4.read4Bytes(ChannelBuffers.copiedBuffer(testAddresses[i]));
             assertEquals(testInts[i], ip.getInt());
             assertArrayEquals(testAddresses[i], ip.getBytes());
             assertEquals(testStrings[i], ip.toString());
@@ -86,4 +107,31 @@
             }
         }
     }
+    
+    @SuppressWarnings("unchecked")
+    @Test
+    public void testOfPossiblyMasked() throws OFParseError, OFShortRead {
+        for (int i = 0; i < ipsWithMask.length; i++) {
+            OFValueType value = IPv4WithMask.ofPossiblyMasked(ipsWithMask[i]);
+            if (value instanceof IPv4 && !hasMask[i]) {
+                // Types OK, check values
+                IPv4 ip = (IPv4)value;
+                assertArrayEquals(ipsWithMaskValues[i][0], ip.getBytes());
+            } else if (value instanceof Masked && hasMask[i]) {
+                Masked<IPv4> ip = null;
+                try {
+                    ip = (Masked<IPv4>)value;
+                } catch (ClassCastException e) {
+                    fail("Invalid Masked<T> type.");
+                }
+                // Types OK, check values
+                assertArrayEquals(ipsWithMaskValues[i][0], ip.getValue().getBytes());
+                assertArrayEquals(ipsWithMaskValues[i][1], ip.getMask().getBytes());
+            } else if (value instanceof IPv4) {
+                fail("Expected masked IPv4, got unmasked IPv4.");
+            } else {
+                fail("Expected unmasked IPv4, got masked IPv4.");
+            }
+        }
+    }
 }
diff --git a/java_gen/pre-written/src/test/java/org/openflow/types/IPv6Test.java b/java_gen/pre-written/src/test/java/org/openflow/types/IPv6Test.java
index 9782429..f2f6fe8 100644
--- a/java_gen/pre-written/src/test/java/org/openflow/types/IPv6Test.java
+++ b/java_gen/pre-written/src/test/java/org/openflow/types/IPv6Test.java
@@ -21,6 +21,72 @@
             "ffe0::",
             "1:2:3:4:5:6:7:8"
     };
+    
+    String[] ipsWithMask = {
+                            "1::1/80",
+                            "1:2:3:4::/ffff:ffff:ffff:ff00::",
+                            "ffff:ffee:1::/ff00:ff00:ff00:ff00::",
+                            "8:8:8:8:8:8:8:8",
+    };
+    
+    byte[][] masks = {
+                    new byte[] { (byte)0xff, (byte)0xff, (byte)0xff, (byte)0xff, 
+                                 (byte)0xff, (byte)0xff, (byte)0xff, (byte)0xff, 
+                                 (byte)0xff, (byte)0xff, (byte)0x00, (byte)0x00, 
+                                 (byte)0x00, (byte)0x00, (byte)0x00, (byte)0x00 },
+                    new byte[] { (byte)0xff, (byte)0xff, (byte)0xff, (byte)0xff, 
+                                 (byte)0xff, (byte)0xff, (byte)0xff, (byte)0x00, 
+                                 (byte)0x00, (byte)0x00, (byte)0x00, (byte)0x00, 
+                                 (byte)0x00, (byte)0x00, (byte)0x00, (byte)0x00 },
+                    new byte[] { (byte)0xff, (byte)0x00, (byte)0xff, (byte)0x00, 
+                                 (byte)0xff, (byte)0x00, (byte)0xff, (byte)0x00, 
+                                 (byte)0x00, (byte)0x00, (byte)0x00, (byte)0x00, 
+                                 (byte)0x00, (byte)0x00, (byte)0x00, (byte)0x00 },
+                    new byte[] { (byte)0x00, (byte)0x00, (byte)0x00, (byte)0x00, 
+                                 (byte)0x00, (byte)0x00, (byte)0x00, (byte)0x00, 
+                                 (byte)0x00, (byte)0x00, (byte)0x00, (byte)0x00, 
+                                 (byte)0x00, (byte)0x00, (byte)0x00, (byte)0x00 }
+    };
+    
+    boolean[] hasMask = {
+                         true,
+                         true,
+                         true,
+                         false
+    };
+
+    @Test
+    public void testMasked() throws UnknownHostException {
+        for(int i=0; i < ipsWithMask.length; i++ ) {
+            OFValueType value = IPv6WithMask.ofPossiblyMasked(ipsWithMask[i]);
+            if (value instanceof IPv6 && !hasMask[i]) {
+                // Types OK, check values
+                IPv6 ip = (IPv6)value;
+                InetAddress inetAddress = InetAddress.getByName(ipsWithMask[i]);
+
+                assertArrayEquals(ip.getBytes(), inetAddress.getAddress());
+                assertEquals(ipsWithMask[i], ip.toString());
+            } else if (value instanceof IPv6WithMask && hasMask[i]) {
+                IPv6WithMask ip = null;
+                try {
+                    ip = (IPv6WithMask)value;
+                } catch (ClassCastException e) {
+                    fail("Invalid Masked<T> type.");
+                }
+                // Types OK, check values
+                InetAddress inetAddress = InetAddress.getByName(ipsWithMask[i].substring(0, ipsWithMask[i].indexOf('/')));
+
+                assertArrayEquals(ip.value.getBytes(), inetAddress.getAddress());
+                assertEquals(ipsWithMask[i].substring(0, ipsWithMask[i].indexOf('/')), ip.value.toString());
+                assertArrayEquals(masks[i], ip.mask.getBytes());
+            } else if (value instanceof IPv6) {
+                fail("Expected masked IPv6, got unmasked IPv6.");
+            } else {
+                fail("Expected unmasked IPv6, got masked IPv6.");
+            }
+        }
+    }
+
 
     @Test
     public void testOfString() throws UnknownHostException {
@@ -47,7 +113,7 @@
     public void testReadFrom() throws OFParseError, OFShortRead, UnknownHostException {
         for(int i=0; i < testStrings.length; i++ ) {
             byte[] bytes = Inet6Address.getByName(testStrings[i]).getAddress();
-            IPv6 ip = IPv6.SERIALIZER_V12.readFrom(ChannelBuffers.copiedBuffer(bytes));
+            IPv6 ip = IPv6.read16Bytes(ChannelBuffers.copiedBuffer(bytes));
             assertEquals(testStrings[i], ip.toString());
             assertArrayEquals(bytes, ip.getBytes());
         }
diff --git a/java_gen/pre-written/src/test/java/org/openflow/types/MacAddressTest.java b/java_gen/pre-written/src/test/java/org/openflow/types/MacAddressTest.java
index f6326d1..78728e1 100644
--- a/java_gen/pre-written/src/test/java/org/openflow/types/MacAddressTest.java
+++ b/java_gen/pre-written/src/test/java/org/openflow/types/MacAddressTest.java
@@ -64,7 +64,7 @@
     @Test
     public void testReadFrom() throws OFParseError, OFShortRead {
         for(int i=0; i < testAddresses.length; i++ ) {
-            MacAddress ip = MacAddress.SERIALIZER_V10.readFrom(ChannelBuffers.copiedBuffer(testAddresses[i]));
+            MacAddress ip = MacAddress.read6Bytes(ChannelBuffers.copiedBuffer(testAddresses[i]));
             assertEquals(testInts[i], ip.getLong());
             assertArrayEquals(testAddresses[i], ip.getBytes());
             assertEquals(testStrings[i], ip.toString());