diff --git a/Makefile b/Makefile
index eef6313..cb60398 100644
--- a/Makefile
+++ b/Makefile
@@ -68,8 +68,9 @@
 
 java: .loxi_ts.java
 
-.loxi_ts.java: ${LOXI_JAVA_FILES} ${LOXI_TEMPLATE_FILES} ${INPUT_FILES}
+.loxi_ts.java: ${LOXI_PY_FILES} ${LOXI_TEMPLATE_FILES} ${INPUT_FILES}
 	./loxigen.py --install-dir=${LOXI_OUTPUT_DIR} --lang=java
+	cd ${LOXI_OUTPUT_DIR}/openflowj; mvn package
 	touch $@
 
 
@@ -90,6 +91,7 @@
 	./utest/test_parser.py
 	./utest/test_frontend.py
 	./utest/test_test_data.py
+	./utest/test_generic_utils.py
 
 check-py: python
 	PYTHONPATH=${LOXI_OUTPUT_DIR}/pyloxi:. python py_gen/tests/generic_util.py
diff --git a/c_gen/c_test_gen.py b/c_gen/c_test_gen.py
index ff111f8..9910b7f 100644
--- a/c_gen/c_test_gen.py
+++ b/c_gen/c_test_gen.py
@@ -81,6 +81,7 @@
         uint16_t="val16",
         uint32_t="val32",
         uint64_t="val64",
+        of_ipv4_t="ipv4",
         of_port_no_t="port_no",
         of_fm_cmd_t="fm_cmd",
         of_wc_bmap_t="wc_bmap",
@@ -107,7 +108,7 @@
 
 integer_types = ["uint8_t", "uint16_t", "uint32_t", "uint64_t",
                  "of_port_no_t", "of_fm_cmd_t", "of_wc_bmap_t",
-                 "of_match_bmap_t"]
+                 "of_match_bmap_t", "of_ipv4_t"]
 string_types = [ "of_port_name_t", "of_table_name_t",
                 "of_desc_str_t", "of_serial_num_t", "of_mac_addr_t",
                 "of_ipv6_t"]
diff --git a/c_gen/templates/loci_show.h b/c_gen/templates/loci_show.h
index acb06b8..b28b807 100644
--- a/c_gen/templates/loci_show.h
+++ b/c_gen/templates/loci_show.h
@@ -74,7 +74,7 @@
  */
 #define LOCI_SHOW_u32_ipv6_flabel(writer, cookie, val)     LOCI_SHOW_u32(writer, cookie, val)
 #define LOCI_SHOW_u8_vlan_pcp(writer, cookie, val)         LOCI_SHOW_u8(writer, cookie, val)
-#define LOCI_SHOW_u32_ipv4_src(writer, cookie, val)        LOCI_SHOW_ipv4(writer, cookie, val)
+#define LOCI_SHOW_ipv4_ipv4_src(writer, cookie, val)        LOCI_SHOW_ipv4(writer, cookie, val)
 #define LOCI_SHOW_ipv6_ipv6_dst(writer, cookie, val)       LOCI_SHOW_ipv6(writer, cookie, val)
 #define LOCI_SHOW_u32_arp_tpa(writer, cookie, val)         LOCI_SHOW_ipv4(writer, cookie, val)
 #define LOCI_SHOW_u8_icmpv6_type(writer, cookie, val)      LOCI_SHOW_u8(writer, cookie, val)
@@ -99,7 +99,7 @@
 #define LOCI_SHOW_u8_ip_ecn(writer, cookie, val)           LOCI_SHOW_u8(writer, cookie, val)
 #define LOCI_SHOW_u16_udp_dst(writer, cookie, val)         LOCI_SHOW_u16(writer, cookie, val)
 #define LOCI_SHOW_port_no_in_phy_port(writer, cookie, val) LOCI_SHOW_port_no(writer, cookie, val)
-#define LOCI_SHOW_u32_ipv4_dst(writer, cookie, val)        LOCI_SHOW_ipv4(writer, cookie, val)
+#define LOCI_SHOW_ipv4_ipv4_dst(writer, cookie, val)        LOCI_SHOW_ipv4(writer, cookie, val)
 #define LOCI_SHOW_mac_eth_src(writer, cookie, val)         LOCI_SHOW_mac(writer, cookie, val)
 #define LOCI_SHOW_u16_udp_src(writer, cookie, val)         LOCI_SHOW_u16(writer, cookie, val)
 #define LOCI_SHOW_mac_ipv6_nd_tll(writer, cookie, val)     LOCI_SHOW_mac(writer, cookie, val)
@@ -266,8 +266,8 @@
 #define LOCI_SHOW_u64_metadata_mask(writer, cookie, val) LOCI_SHOW_x64(writer, cookie, val)
 #define LOCI_SHOW_mac_eth_src_mask(writer, cookie, val) LOCI_SHOW_mac(writer, cookie, val)
 #define LOCI_SHOW_mac_eth_dst_mask(writer, cookie, val) LOCI_SHOW_mac(writer, cookie, val)
-#define LOCI_SHOW_u32_ipv4_src_mask(writer, cookie, val) LOCI_SHOW_ipv4(writer, cookie, val)
-#define LOCI_SHOW_u32_ipv4_dst_mask(writer, cookie, val) LOCI_SHOW_ipv4(writer, cookie, val)
+#define LOCI_SHOW_ipv4_ipv4_src_mask(writer, cookie, val) LOCI_SHOW_ipv4(writer, cookie, val)
+#define LOCI_SHOW_ipv4_ipv4_dst_mask(writer, cookie, val) LOCI_SHOW_ipv4(writer, cookie, val)
 #define LOCI_SHOW_u32_curr_speed(writer, cookie, val) LOCI_SHOW_u32(writer, cookie, val)
 #define LOCI_SHOW_u32_max_speed(writer, cookie, val) LOCI_SHOW_u32(writer, cookie, val)
 #define LOCI_SHOW_match_bmap_match(writer, cookie, val) LOCI_SHOW_match_bmap(writer, cookie, val)
@@ -328,11 +328,12 @@
 #define LOCI_SHOW_u32_service(writer, cookie, val) LOCI_SHOW_u32(writer, cookie, val)
 #define LOCI_SHOW_u32_status(writer, cookie, val) LOCI_SHOW_u32(writer, cookie, val)
 #define LOCI_SHOW_u16_subtype(writer, cookie, val) LOCI_SHOW_u16(writer, cookie, val)
-#define LOCI_SHOW_u32_ipv4_addr(writer, cookie, val) LOCI_SHOW_ipv4(writer, cookie, val)
-#define LOCI_SHOW_u32_ipv4_netmask(writer, cookie, val) LOCI_SHOW_ipv4(writer, cookie, val)
+#define LOCI_SHOW_ipv4_ipv4_addr(writer, cookie, val) LOCI_SHOW_ipv4(writer, cookie, val)
+#define LOCI_SHOW_ipv4_ipv4_netmask(writer, cookie, val) LOCI_SHOW_ipv4(writer, cookie, val)
 #define LOCI_SHOW_u8_l2_table_enable(writer, cookie, val) LOCI_SHOW_u8(writer, cookie, val)
 #define LOCI_SHOW_u16_l2_table_priority(writer, cookie, val) LOCI_SHOW_u16(writer, cookie, val)
-
+#define LOCI_SHOW_ipv4_value(writer, cookie, val) LOCI_SHOW_ipv4(writer, cookie, val)
+#define LOCI_SHOW_ipv4_value_mask(writer, cookie, val) LOCI_SHOW_ipv4(writer, cookie, val)
 
 
 #endif /* _LOCI_SHOW_H_ */
diff --git a/c_gen/templates/of_wire_buf.h b/c_gen/templates/of_wire_buf.h
index 9e91b9b..8750565 100644
--- a/c_gen/templates/of_wire_buf.h
+++ b/c_gen/templates/of_wire_buf.h
@@ -348,6 +348,38 @@
     buf_u32_set(OF_WIRE_BUFFER_INDEX(wbuf, offset), value);
 }
 
+
+/**
+ * Get a uint32_t scalar from a wire buffer
+ * @param wbuf The pointer to the wire buffer structure
+ * @param offset Offset in the wire buffer
+ * @param value Pointer to where to put value
+ *
+ * The underlying buffer accessor funtions handle endian and alignment.
+ */
+
+static inline void
+of_wire_buffer_ipv4_get(of_wire_buffer_t *wbuf, int offset, of_ipv4_t *value)
+{
+    of_wire_buffer_u32_get(wbuf, offset, value);
+}
+
+/**
+ * Set a ipv4 (uint32_t) scalar in a wire buffer
+ * @param wbuf The pointer to the wire buffer structure
+ * @param offset Offset in the wire buffer
+ * @param value The value to store
+ *
+ * The underlying buffer accessor funtions handle endian and alignment.
+ */
+
+static inline void
+of_wire_buffer_ipv4_set(of_wire_buffer_t *wbuf, int offset, of_ipv4_t value)
+{
+    of_wire_buffer_u32_set(wbuf, offset, value);
+}
+
+
 /**
  * Get a uint64_t scalar from a wire buffer
  * @param wbuf The pointer to the wire buffer structure
diff --git a/java_gen/.classpath b/java_gen/.classpath
new file mode 100644
index 0000000..050cd9c
--- /dev/null
+++ b/java_gen/.classpath
@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<classpath>
+	<classpathentry kind="lib" path="pre-written/lib/netty-3.2.6.Final.jar"/>
+	<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER"/>
+	<classpathentry kind="output" path="bin"/>
+</classpath>
diff --git a/java_gen/.project b/java_gen/.project
new file mode 100644
index 0000000..b347bd6
--- /dev/null
+++ b/java_gen/.project
@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<projectDescription>
+	<name>openflowj-loxi</name>
+	<comment></comment>
+	<projects>
+	</projects>
+	<buildSpec>
+		<buildCommand>
+			<name>org.eclipse.jdt.core.javabuilder</name>
+			<arguments>
+			</arguments>
+		</buildCommand>
+	</buildSpec>
+	<natures>
+		<nature>org.eclipse.jdt.core.javanature</nature>
+	</natures>
+</projectDescription>
diff --git a/java_gen/codegen.py b/java_gen/codegen.py
new file mode 100644
index 0000000..0765c91
--- /dev/null
+++ b/java_gen/codegen.py
@@ -0,0 +1,116 @@
+# Copyright 2013, Big Switch Networks, Inc.
+#
+# LoxiGen is licensed under the Eclipse Public License, version 1.0 (EPL), with
+# the following special exception:
+#
+# LOXI Exception
+#
+# As a special exception to the terms of the EPL, you may distribute libraries
+# generated by LoxiGen (LoxiGen Libraries) under the terms of your choice, provided
+# that copyright and licensing notices generated by LoxiGen are not altered or removed
+# from the LoxiGen Libraries and the notice provided below is (i) included in
+# the LoxiGen Libraries, if distributed in source code form and (ii) included in any
+# documentation for the LoxiGen Libraries, if distributed in binary form.
+#
+# Notice: "Copyright 2013, Big Switch Networks, Inc. This library was generated by the LoxiGen Compiler."
+#
+# You may not use this file except in compliance with the EPL or LOXI Exception. You may obtain
+# a copy of the EPL at:
+#
+# http://www.eclipse.org/legal/epl-v10.html
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# EPL for the specific language governing permissions and limitations
+# under the EPL.
+
+"""
+@brief Main Java Generation module
+"""
+
+import pdb
+import os
+import shutil
+
+import of_g
+from loxi_ir import *
+import lang_java
+
+import loxi_utils.loxi_utils as loxi_utils
+
+import java_gen.java_model as java_model
+
+def gen_all_java(out, name):
+    basedir= '%s/openflowj' % of_g.options.install_dir
+    srcdir = "%s/src/main/java/" % basedir
+    print "Outputting to %s" % basedir
+    if os.path.exists(basedir):
+        shutil.rmtree(basedir)
+    os.makedirs(basedir)
+    copy_prewrite_tree(basedir)
+
+    gen = JavaGenerator(srcdir)
+    gen.create_of_interfaces()
+    gen.create_of_classes()
+    gen.create_of_const_enums()
+
+    with open('%s/README.java-lang' % os.path.dirname(__file__)) as readme_src:
+        out.writelines(readme_src.readlines())
+    out.close()
+
+
+class JavaGenerator(object):
+    templates_dir = os.path.join(os.path.dirname(os.path.realpath(__file__)), 'templates')
+
+    def __init__(self, basedir):
+        self.basedir = basedir
+        self.java_model = java_model.model
+
+    def render_class(self, clazz, template, **context):
+        context['class_name'] = clazz.name
+        context['package'] = clazz.package
+
+        filename = os.path.join(self.basedir, "%s/%s.java" % (clazz.package.replace(".", "/"), clazz.name))
+        dirname = os.path.dirname(filename)
+        if not os.path.exists(dirname):
+            os.makedirs(dirname)
+        prefix = '//::(?=[ \t]|$)'
+        print "filename: %s" % filename
+        with open(filename, "w") as f:
+            loxi_utils.render_template(f, template, [self.templates_dir], context, prefix=prefix)
+
+    def create_of_const_enums(self):
+        for enum in self.java_model.enums:
+            if enum.name in ["OFPort"]:
+                continue
+            self.render_class(clazz=enum,
+                    template='const.java', enum=enum, all_versions=self.java_model.versions)
+
+    def create_of_interfaces(self):
+        """ Create the base interfaces for of classes"""
+        for interface in self.java_model.interfaces:
+            #if not utils.class_is_message(interface.c_name):
+            #    continue
+            self.render_class(clazz=interface,
+                    template="of_interface.java", msg=interface)
+
+    def create_of_classes(self):
+        """ Create the OF classes with implementations for each of the interfaces and versions """
+        for interface in self.java_model.interfaces:
+            if interface.name == "OFTableMod":
+                continue
+            if not loxi_utils.class_is_message(interface.c_name) and not loxi_utils.class_is_oxm(interface.c_name):
+                continue
+            for java_class in interface.versioned_classes:
+                self.render_class(clazz=java_class,
+                        template='of_class.java', version=java_class.version, msg=java_class,
+                        impl_class=java_class.name)
+
+def copy_prewrite_tree(basedir):
+    """ Recursively copy the directory structure from ./java_gen/pre-write
+       into $basedir"""
+    print "Copying pre-written files into %s" % basedir
+    #subprocess.call("cd java_gen/pre-written && tar cpf - pom.xml | ( cd ../../%s && tar xvpf - )" % basedir,
+    #        shell=True)
+    os.symlink(os.path.abspath("%s/pre-written/pom.xml" %  os.path.dirname(__file__)), "%s/pom.xml" % basedir)
diff --git a/java_gen/java_code_gen.py b/java_gen/java_code_gen.py
deleted file mode 100644
index 91c89a7..0000000
--- a/java_gen/java_code_gen.py
+++ /dev/null
@@ -1,68 +0,0 @@
-import of_g
-import pdb
-import os
-
-import lang_java
-
-import loxi_utils.loxi_utils as loxi_utils
-
-import java_gen.msgs as msgs
-import java_gen.java_utils as java_utils
-
-def gen_all_java(out, name):
-    """ Generate all of the java files
-
-    @param out is an open file handle to a file called README
-    @param name should be 'README' and is ignored for the java
-        driver
-    """
-    messages = list()
-    actions = list()
-    instructions = list()
-    matches = list()
-    stat_types = list()
-    queue_prop = list()
-    lists = list()
-    for cls in of_g.unified:
-        print "! Classifying %s" % cls
-        if cls in [ 'of_stats_reply', 'of_flow_mod', 'of_stats_request' ] :
-            continue # doesn't work?!
-        if loxi_utils.class_is_stats_message(cls):
-            stat_types.append(cls)
-        elif loxi_utils.class_is_message(cls):
-            messages.append(cls)
-        elif loxi_utils.class_is_action(cls):
-            actions.append(cls)
-        elif loxi_utils.class_is_instruction(cls):
-            instructions.append(cls)
-        elif loxi_utils.class_is_oxm(cls):
-            matches.append(cls)
-        elif loxi_utils.class_is_queue_prop(cls):
-            queue_prop.append(cls)
-        elif loxi_utils.class_is_list(cls):
-            lists.append(cls)
-        else:
-            print "Skipping Unknown class object %s" % str(cls)
-    print "Parsed "
-    print "  Messages: %d" % len(messages)
-    print "  Actions: %d" % len(actions)
-    print "  Instructions: %d" % len(instructions)
-    print "  OXM matches: %d" % len(matches)
-    print "  Stat types: %d" % len(stat_types)
-    print "  Queue properties: %d" % len(queue_prop)
-    print "  Lists: %d" % len(lists)
-    target_dir='loxi_output/openflowj'
-    basedir="%s/%s/" % (
-            target_dir,
-            lang_java.file_to_subdir_map['base_java'])
-    srcdir = "%s/src/main/java/org/openflow/protocol" % basedir
-    print "Outputting to %s" % basedir
-    if not os.path.exists(basedir):
-        os.makedirs(basedir)
-    java_utils.copy_prewrite_tree(basedir)
-    msgs.create_message_interfaces(messages,srcdir)
-    msgs.create_message_by_version(messages,srcdir)
-    msgs.create_of_type_enum(messages,srcdir)
-    with open('README.java-lang') as readme_src:
-        out.writelines(readme_src.readlines())
-    out.close()
diff --git a/java_gen/java_model.py b/java_gen/java_model.py
index 062a64d..3755c82 100644
--- a/java_gen/java_model.py
+++ b/java_gen/java_model.py
@@ -1,19 +1,103 @@
+# Copyright 2013, Big Switch Networks, Inc.
+#
+# LoxiGen is licensed under the Eclipse Public License, version 1.0 (EPL), with
+# the following special exception:
+#
+# LOXI Exception
+#
+# As a special exception to the terms of the EPL, you may distribute libraries
+# generated by LoxiGen (LoxiGen Libraries) under the terms of your choice, provided
+# that copyright and licensing notices generated by LoxiGen are not altered or removed
+# from the LoxiGen Libraries and the notice provided below is (i) included in
+# the LoxiGen Libraries, if distributed in source code form and (ii) included in any
+# documentation for the LoxiGen Libraries, if distributed in binary form.
+#
+# Notice: "Copyright 2013, Big Switch Networks, Inc. This library was generated by the LoxiGen Compiler."
+#
+# You may not use this file except in compliance with the EPL or LOXI Exception. You may obtain
+# a copy of the EPL at:
+#
+# http://www.eclipse.org/legal/epl-v10.html
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# EPL for the specific language governing permissions and limitations
+# under the EPL.
+
 # Prototype of an Intermediate Object model for the java code generator
 # A lot of this stuff could/should probably be merged with the python utilities
 
-import of_g
+import collections
+from collections import namedtuple, defaultdict
+import logging
 import os
 import pdb
 import re
 
+from generic_utils import find, memoize, OrderedSet
+import of_g
+from loxi_ir import *
 import loxi_front_end.type_maps as type_maps
 import loxi_utils.loxi_utils as utils
 import py_gen.util as py_utils
 
-import java_gen.java_utils as java_utils
-ignore_fields = ['version', 'xid', 'length', 'type' ]
+import java_gen.java_type as java_type
 
-protected_fields = ['version', 'length']
+class JavaModel(object):
+    write_blacklist = defaultdict(lambda: set(), OFOxm=set(('typeLen',)))
+    virtual_interfaces = set(['OFOxm' ])
+
+    @property
+    @memoize
+    def versions(self):
+        return OrderedSet( JavaOFVersion(raw_version) for raw_version in of_g.target_version_list )
+
+    @property
+    @memoize
+    def interfaces(self):
+        version_map_per_class = collections.defaultdict(lambda: {})
+
+        for raw_version, of_protocol in of_g.ir.items():
+            jversion = JavaOFVersion(of_protocol.wire_version)
+
+            for of_class in of_protocol.classes:
+                version_map_per_class[of_class.name][jversion] = of_class
+
+        interfaces = []
+        for class_name, version_map in version_map_per_class.items():
+            interfaces.append(JavaOFInterface(class_name, version_map))
+
+        return interfaces
+
+    @property
+    @memoize
+    def enums(self):
+        enum_entry_version_value_map = collections.defaultdict(lambda: collections.defaultdict(lambda: collections.OrderedDict()))
+
+        for version in self.versions:
+            of_protocol = of_g.ir[version.int_version]
+            for enum in of_protocol.enums:
+                for entry_name, entry_value in enum.values:
+                    enum_entry_version_value_map[enum.name][entry_name][version] = entry_value
+
+        enums = [ JavaEnum(name, entry_version_value_map) for name, entry_version_value_map
+                        in enum_entry_version_value_map.items() ]
+
+        return enums
+
+    @memoize
+    def enum_by_name(self, name):
+        try:
+            return find(self.enums, lambda e: e.name == name)
+        except KeyError:
+            raise KeyError("Could not find enum with name %s" % name)
+
+model = JavaModel()
+
+#######################################################################
+### OFVersion
+#######################################################################
 
 class JavaOFVersion(object):
     """ Models a version of OpenFlow. contains methods to convert the internal
@@ -29,17 +113,193 @@
     def constant_version(self):
         return "OF_" + self.of_version
 
+    def __repr__(self):
+        return "JavaOFVersion(%d)" % self.int_version
+
     def __str__(self):
         return of_g.param_version_names[self.int_version]
 
-class JavaProperty(object):
-    """ Models a property (member) of an openflow class. """
-    def __init__(self, msg, java_type, c_type, name, c_name):
-        self.msg = msg
-        self.java_type = java_type
-        self.c_type = c_type
-        self.name = name
+    def __hash__(self):
+        return hash(self.int_version)
+
+    def __eq__(self, other):
+        if other is None or type(self) != type(other):
+            return False
+        return (self.int_version,) == (other.int_version,)
+
+#######################################################################
+### Interface
+#######################################################################
+
+class JavaOFInterface(object):
+    """ Models an OpenFlow Message class for the purpose of the java class.
+        Version agnostic, in contrast to the loxi_ir python model.
+    """
+    def __init__(self, c_name, version_map):
         self.c_name = c_name
+        self.version_map = version_map
+        self.name = java_type.name_c_to_caps_camel(c_name)
+        self.builder_name = self.name + "Builder"
+        self.constant_name = c_name.upper().replace("OF_", "")
+
+        pck_suffix, parent_interface = self.class_info()
+        self.package = "org.openflow.protocol.%s" % pck_suffix if pck_suffix else "org.openflow.protocol"
+        if self.name != parent_interface:
+            self.parent_interface = parent_interface
+        else:
+            self.parent_interface = None
+
+    def class_info(self):
+        if re.match(r'OFFlow(Add|Modify(Strict?)|Deleted(Strict?))', self.name):
+            return ("", "OFFlowMod")
+        elif utils.class_is_message(self.c_name):
+            return ("", "OFMessage")
+        elif utils.class_is_action(self.c_name):
+            return ("action", "OFAction")
+        elif utils.class_is_oxm(self.c_name):
+            return ("oxm", "OFOxm")
+        elif utils.class_is_instruction(self.c_name):
+            return ("instruction", "OFInstruction")
+        elif utils.class_is_meter_band(self.c_name):
+            return ("meterband", "OFMeterBand")
+        else:
+            return ("", None)
+
+    @property
+    @memoize
+    def members(self):
+        all_versions = []
+        member_map = collections.OrderedDict()
+
+        for (version, of_class) in self.version_map.items():
+            for of_member in of_class.members:
+                if isinstance(of_member, OFLengthMember) or \
+                   isinstance(of_member, OFFieldLengthMember) or \
+                   isinstance(of_member, OFPadMember):
+                    continue
+                if of_member.name not in member_map:
+                    member_map[of_member.name] = JavaMember.for_of_member(self, of_member)
+
+        return member_map.values()
+
+    @property
+    @memoize
+    def is_virtual(self):
+        return self.name in model.virtual_interfaces
+
+    @property
+    @memoize
+    def all_versions(self):
+        return self.version_map.keys()
+
+    def versioned_class(self, version):
+        return JavaOFClass(self, version, self.version_map[version])
+
+    @property
+    @memoize
+    def versioned_classes(self):
+        if self.is_virtual:
+            return []
+        else:
+            return [ self.versioned_class(version) for version in self.all_versions ]
+
+#######################################################################
+### (Versioned) Classes
+#######################################################################
+
+class JavaOFClass(object):
+    """ Models an OpenFlow Message class for the purpose of the java class.
+        Version specific child of a JavaOFInterface
+    """
+    def __init__(self, interface, version, ir_class):
+        self.interface = interface
+        self.ir_class = ir_class
+        self.c_name = self.ir_class.name
+        self.version = version
+        self.constant_name = self.c_name.upper().replace("OF_", "")
+        self.package = "org.openflow.protocol.ver%s" % version.of_version
+
+    @property
+    def name(self):
+        return "%sVer%s" % (self.interface.name, self.version.of_version)
+
+    @property
+    def length(self):
+        if self.is_fixed_length:
+            return self.min_length
+        else:
+            raise Exception("No fixed length for class %s, version %s" % (self.name, self.version))
+
+    @property
+    def min_length(self):
+        id_tuple = (self.ir_class.name, self.version.int_version)
+        return of_g.base_length[id_tuple] if id_tuple in of_g.base_length else -1
+
+    @property
+    def is_fixed_length(self):
+        return (self.ir_class.name, self.version.int_version) in of_g.is_fixed_length
+
+    def all_properties(self):
+        return self.interface.members
+
+    def get_member(self, name):
+        for m in self.members:
+            if m.name == name:
+                return m
+
+    @property
+    @memoize
+    def data_members(self):
+        return [ prop for prop in self.members if prop.is_data ]
+
+    @property
+    @memoize
+    def fixed_value_members(self):
+        return [ prop for prop in self.members if prop.is_fixed_value ]
+
+    @property
+    @memoize
+    def public_members(self):
+        return [ prop for prop in self.members if prop.is_public ]
+
+    @property
+    @memoize
+    def members(self):
+        members = [ JavaMember.for_of_member(self, of_member) for of_member in self.ir_class.members ]
+        return members
+
+    def all_versions(self):
+        return [ JavaOFVersion(int_version)
+                 for int_version in of_g.unified[self.c_name]
+                 if int_version != 'union' and int_version != 'object_id' ]
+
+    def version_is_inherited(self, version):
+        return 'use_version' in of_g.unified[self.ir_class.name][version.int_version]
+
+    def inherited_from(self, version):
+        return JavaOFVersion(of_g.unified[self.ir_class.name][version.int_version]['use_version'])
+
+    @property
+    def is_virtual(self):
+        return type_maps.class_is_virtual(self.c_name)
+
+    @property
+    def is_extension(self):
+        return type_maps.message_is_extension(self.c_name, -1)
+
+#######################################################################
+### Member
+#######################################################################
+
+
+class JavaMember(object):
+    """ Models a property (member) of an openflow class. """
+    def __init__(self, msg, name, java_type, member):
+        self.msg = msg
+        self.name = name
+        self.java_type = java_type
+        self.member = member
+        self.c_name = self.member.name if(hasattr(self.member, "name")) else ""
 
     @property
     def title_name(self):
@@ -51,13 +311,18 @@
 
     @property
     def default_name(self):
-        return "DEFAULT_"+self.constant_name
+        if self.is_fixed_value:
+            return self.constant_name
+        else:
+            return "DEFAULT_"+self.constant_name
 
     @property
     def default_value(self):
         java_type = self.java_type.public_type;
 
-        if re.match(r'List.*', java_type):
+        if self.is_fixed_value:
+            return self.enum_value
+        elif re.match(r'List.*', java_type):
             return "Collections.emptyList()"
         elif java_type == "boolean":
             return "false";
@@ -67,114 +332,161 @@
             return "null";
 
     @property
+    def enum_value(self):
+        if self.name == "version":
+            return "OFVersion.%s" % self.msg.version.constant_version
+
+        java_type = self.java_type.public_type;
+        try:
+            global model
+            enum = model.enum_by_name(java_type)
+            entry = enum.entry_by_version_value(self.msg.version, self.value)
+            return "%s.%s" % ( enum.name, entry.name)
+        except KeyError, e:
+            print e.message
+            return self.value
+
+    @property
     def is_pad(self):
-        return self.c_name.startswith("pad")
+        return isinstance(self.member, OFPadMember)
+
+    def is_type_value(self, version=None):
+        if(version==None):
+            return any(self.is_type_value(version) for version in self.msg.all_versions)
+        try:
+            return self.c_name in get_type_values(self.msg.c_name, version.int_version)
+        except:
+            return False
+
+    @property
+    def is_field_length_value(self):
+        return isinstance(self.member, OFFieldLengthMember)
+
+    @property
+    def is_length_value(self):
+        return isinstance(self.member, OFLengthMember)
+
+    @property
+    def is_public(self):
+        return not (self.is_pad or self.is_length_value)
+
+    @property
+    def is_data(self):
+        return isinstance(self.member, OFDataMember) and self.name != "version"
+
+    @property
+    def is_fixed_value(self):
+        return hasattr(self.member, "value") or self.name == "version" \
+                or ( self.name == "length" and self.msg.is_fixed_length) \
+                or ( self.name == "len" and self.msg.is_fixed_length)
+
+    @property
+    def value(self):
+        if self.name == "version":
+            return self.msg.version.int_version
+        elif self.name == "length" or self.name == "len":
+            return self.msg.length
+        elif self.java_type.public_type in ("int", "short", "byte") and self.member.value > 100:
+            return "0x%x" % self.member.value
+        else:
+            return self.member.value
+
+    @property
+    def is_writeable(self):
+        return self.is_data and not self.name in model.write_blacklist[self.msg.name]
+
+    def get_type_value_info(self, version):
+        return get_type_values(msg.c_name, version.int_version)[self.c_name]
 
     @property
     def length(self):
-        count, base = utils.type_dec_to_count_base(self.c_type)
-        return of_g.of_base_types[base]['bytes'] * count
+        if hasattr(self.member, "length"):
+            return self.member.length
+        else:
+            count, base = utils.type_dec_to_count_base(self.member.type)
+            return of_g.of_base_types[base]['bytes'] * count
 
     @staticmethod
-    def for_field(msg, field, c_name=None):
-        if not c_name:
-            c_name = field['name']
-
-        name = java_utils.name_c_to_camel(c_name)
-        java_type = java_utils.convert_to_jtype(msg.c_name, c_name, field['m_type'])
-        c_type = field['m_type']
-        return JavaProperty(msg, java_type, c_type, name, c_name)
+    def for_of_member(java_class, member):
+        if isinstance(member, OFPadMember):
+            return JavaMember(None, "", None, member)
+        else:
+            if member.name == 'len':
+                name = 'length'
+            else:
+                name = java_type.name_c_to_camel(member.name)
+            j_type = java_type.convert_to_jtype(java_class.c_name, member.name, member.oftype)
+            return JavaMember(java_class, name, j_type, member)
 
     @property
     def is_universal(self):
+        if not self.msg.c_name in of_g.unified:
+            print("%s not self.unified" % self.msg.c_name)
+            return False
         for version in of_g.unified[self.msg.c_name]:
             if version == 'union' or version =='object_id':
                 continue
             if 'use_version' in of_g.unified[self.msg.c_name][version]:
                 continue
 
-            if not self.c_name in (f['name'] for f in of_g.unified[self.msg.c_name][version]['members']):
+            if not self.member.name in (f['name'] for f in of_g.unified[self.msg.c_name][version]['members']):
                 return False
         return True
 
-class JavaOFMessage(object):
-    """ Models an OpenFlow Message class """
-    def __init__(self, c_name):
-        self.c_name = c_name
-        self.interface_name = java_utils.name_c_to_caps_camel(c_name)
-        self.builder_name = self.interface_name + "Builder"
-        self.constant_name = c_name.upper().replace("OF_", "")
+    def __hash__(self):
+        return hash(self.name)
 
-    def min_length(self, version):
-        return of_g.base_length[(self.c_name, version.int_version)] if (self.c_name, version.int_version) in of_g.base_length else -1
-
-    def is_fixed_length(self, version):
-        return (self.c_name, version.int_version) in of_g.is_fixed_length
-
-    def class_name_for_version(self, version):
-        return self.interface_name + "Ver"+version.of_version
-
-
-    def all_properties(self, skip_pads=True):
-        if 'union' in of_g.unified[self.c_name]:
-            props = []
-            fields = of_g.unified[self.c_name]['union']
-            for field_name in sorted( fields.keys(), key=lambda k: fields[k]['memid']):
-                if field_name in ignore_fields:
-                    continue
-                if skip_pads and field_name.startswith("pad"):
-                    continue
-
-                java_property = JavaProperty.for_field(self, fields[field_name], c_name=field_name)
-                props.append(java_property)
-            return props
-        else:
-            return []
-
-    def all_versions(self):
-        return [ JavaOFVersion(int_version)
-                 for int_version in of_g.unified[self.c_name]
-                 if int_version != 'union' and int_version != 'object_id' ]
-
-    def property_in_version(self, prop, version):
-        if self.version_is_inherited(version):
-            version = self.inherited_from(version)
-
-        if 'members' not in of_g.unified[self.c_name][version.int_version]:
+    def __eq__(self, other):
+        if other is None or type(self) != type(other):
             return False
-        return prop.c_name in (member['name'] for member in of_g.unified[self.c_name][version.int_version]['members'])
+        return (self.name,) == (other.name,)
 
-    def properties_for_version(self, version, skip_pads=True):
-        props = []
-        if self.version_is_inherited(version):
-            version = self.inherited_from(version)
+#######################################################################
+### Enums
+#######################################################################
 
-        for field in of_g.unified[self.c_name][version.int_version]['members']:
-            if field['name'] in ignore_fields:
-                continue
-            if skip_pads and field['name'].startswith("pad"):
-                continue
+class JavaEnum(object):
+    def __init__(self, c_name, entry_version_value_map):
+        self.c_name = c_name
+        self.name   = "OF" + java_type.name_c_to_caps_camel("_".join(c_name.split("_")[1:]))
 
-            java_property = JavaProperty.for_field(self, field, c_name=field['name'])
-            props.append(java_property)
-        return props
+        # Port_features has constants that start with digits
+        self.name_prefix = "PF_" if self.name == "OFPortFeatures" else ""
 
-    def version_is_inherited(self, version):
-        return 'use_version' in of_g.unified[self.c_name][version.int_version]
+        self.entries = [ JavaEnumEntry(self, name, version_value_map)
+                         for (name, version_value_map) in entry_version_value_map.items() ]
+        self.package = "org.openflow.protocol"
 
-    def inherited_from(self, version):
-        return JavaOFVersion(of_g.unified[self.c_name][version.int_version]['use_version'])
-
-    @property
-    def is_virtual(self):
-        return type_maps.class_is_virtual(self.c_name)
-
-    @property
-    def is_extension(self):
-        return type_maps.message_is_extension(self.c_name, -1)
-
-    def wire_type(self, version):
+    @memoize
+    def entry_by_name(self, name):
         try:
-            return py_utils.primary_wire_type(self.c_name, version.int_version)
-        except ValueError, e:
-            return -1
+            return find(self.entries, lambda e: e.name == name)
+        except KeyError:
+            raise KeyError("Enum %s: no entry with name %s" % (self.name, name))
+
+    @memoize
+    def entry_by_c_name(self, name):
+        try:
+            return find(self.entries, lambda e: e.c_name == name)
+        except KeyError:
+            raise KeyError("Enum %s: no entry with c_name %s" % (self.name, name))
+
+    @memoize
+    def entry_by_version_value(self, version, value):
+        try:
+            return find(self.entries, lambda e: e.values[version] == value if version in e.values else False )
+        except KeyError:
+            raise KeyError("Enum %s: no entry with version %s, value %s" % (self.name, version, value))
+
+# values: Map JavaVersion->Value
+class JavaEnumEntry(object):
+    def __init__(self, enum, name, values):
+        self.name = enum.name_prefix + "_".join(name.split("_")[1:]).upper()
+        self.values = values
+
+    def value(self, version):
+        res = self.version_value_map[version]
+        return res
+
+    def all_values(self, versions, not_present=None):
+        return [ self.values[version] if version in self.values else not_present for version in versions ]
diff --git a/java_gen/java_type.py b/java_gen/java_type.py
new file mode 100644
index 0000000..3fa9e81
--- /dev/null
+++ b/java_gen/java_type.py
@@ -0,0 +1,230 @@
+import os
+import errno
+import re
+import subprocess
+import time
+
+def name_c_to_camel(name):
+    """ 'of_stats_reply' -> 'ofStatsReply' """
+    name = re.sub(r'^_','', name)
+    tokens = name.split('_')
+    for i in range(1, len(tokens)):
+            tokens[i] = tokens[i].title()
+    return "".join(tokens)
+
+def name_c_to_caps_camel(name):
+    """ 'of_stats_reply' to 'OFStatsReply' """
+    camel = name_c_to_camel(name.title())
+    if camel.startswith('Of'):
+        return camel.replace('Of','OF',1)
+    else:
+        return camel
+
+
+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):
+        self.pub_type = pub_type    # the type we expose externally, e.g. 'U8'
+        if priv_type is None:
+            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, $name)'  % self.pub_type
+        self._read_op = read_op
+        self._write_op = write_op
+
+    @property
+    def public_type(self):
+        """ return the public type """
+        return self.pub_type
+
+    def priv(self):
+        """ return the public type """
+        return self.priv_type
+
+    def has_priv(self):
+        """ Is the private type different from the public one?"""
+        return self.pub_type != self.priv_type
+
+    def read_op(self, version=None, length=None):
+        if length is None:
+            length = "length - bb.readerIndex()";
+
+        if callable(self._read_op):
+            return self._read_op(version)
+        else:
+            return self._read_op.replace("$length", str(length)).replace("$version", version.of_version)
+
+    def write_op(self, version=None, name=None):
+        if callable(self._write_op):
+            return self._write_op(version, name)
+        else:
+            return self._write_op.replace("$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=lambda version: 'OFPort.ofShort(bb.readShort())' if version.int_version < 2 else 'OFPort.ofInt(bb.readInt())',
+        write_op=lambda version, name: 'bb.writeShort(%s.getShortPortNumber())' % name if version.int_version < 2 else 'bb.writeInt(%s.getPortNumber())' % name)
+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.readFrom(bb)',
+        write_op = '$name.writeTo(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, $name, 32)')
+ipv4 = JType("IPv4",
+        read_op = "IPv4.readFrom(bb)",
+        write_op = "$name.writeTo(bb)")
+ipv6 = JType("IPv6",
+        read_op = "IPv6.readFrom(bb)",
+        write_op = "$name.writeTo(bb)")
+
+default_mtype_to_jtype_convert_map = {
+        'uint8_t' : u8,
+        'uint16_t' : u16,
+        'uint32_t' : u32,
+        'uint64_t' : u64,
+        'uint8_t[1]' : one_byte_array,
+        'uint8_t[2]' : two_byte_array,
+        'uint8_t[3]' : three_byte_array,
+        'uint8_t[4]' : four_byte_array,
+        'uint8_t[5]' : five_byte_array,
+        'uint8_t[6]' : six_byte_array,
+        'uint8_t[7]' : seven_byte_array,
+        'of_port_no_t' : of_port,
+        'list(of_action_t)' : actions_list,
+        'list(of_instruction_t)' : instructions_list,
+        'list(of_bucket_t)': buckets_list,
+        'list(of_port_desc_t)' : port_desc_list,
+        'list(of_packet_queue_t)' : packet_queue_list,
+        'list(of_uint32_t)' : u32_list,
+        'list(of_uint8_t)' : u8_list,
+        'of_octets_t' : octets,
+        'of_match_t': of_match,
+        'of_fm_cmd_t': flow_mod_cmd,
+        'of_mac_addr_t': mac_addr,
+        'of_port_desc_t': port_desc,
+        'of_desc_str_t': desc_str,
+        'of_serial_num_t': serial_num,
+        'of_port_name_t': port_name,
+        'of_table_name_t': table_name,
+        'of_ipv4_t': ipv4,
+        'of_ipv6_t': ipv6,
+        'of_wc_bmap_t': JType("Wildcards")
+        }
+
+## This is where we drop in special case handling for certain types
+exceptions = {
+        'OFPacketIn': {
+            'data' : octets
+            },
+}
+
+
+def make_standard_list_jtype(c_type):
+    m = re.match(r'list\(of_([a-zA-Z_]+)_t\)', c_type)
+    if not m:
+        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, $name)' % java_base_name
+        )
+
+def convert_to_jtype(obj_name, field_name, c_type):
+    """ Convert from a C type ("uint_32") to a java type ("U32")
+    and return a JType object with the size, internal type, and marshalling functions"""
+    if obj_name in exceptions and field_name in exceptions[obj_name]:
+        return exceptions[obj_name][field_name]
+    elif field_name == "type" and c_type == "uint8_t":
+        return JType("OFType", 'byte', size=1, read_op='bb.readByte()',
+        write_op='bb.writeByte($name)')
+    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($name)')
+    elif field_name == "version" and c_type == "uint8_t":
+        return JType("OFVersion", 'byte', size=1, read_op='bb.readByte()',
+        write_op='bb.writeByte($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):
+        return make_standard_list_jtype(c_type)
+    else:
+        print "WARN: Couldn't find java type conversion for '%s' in %s:%s" % (c_type, obj_name, field_name)
+        jtype = name_c_to_caps_camel(re.sub(r'_t$', "", c_type))
+        return JType(jtype)
diff --git a/java_gen/java_utils.py b/java_gen/java_utils.py
deleted file mode 100644
index c55b275..0000000
--- a/java_gen/java_utils.py
+++ /dev/null
@@ -1,215 +0,0 @@
-import os
-import errno
-import re
-import subprocess
-import time
-
-def name_c_to_camel(name):
-    """ 'of_stats_reply' -> 'ofStatsReply' """
-    tokens = name.split('_')
-    for i in range(1, len(tokens)):
-            tokens[i] = tokens[i].title()
-    return "".join(tokens)
-
-def name_c_to_caps_camel(name):
-    """ 'of_stats_reply' to 'OFStatsReply' """
-    camel = name_c_to_camel(name.title())
-    if camel.startswith('Of'):
-        return camel.replace('Of','OF',1)
-    else:
-        return camel
-
-
-class JType(object):
-    """ Wrapper class to hold C to Java type conversion information """
-    def __init__(self, pub_type, priv_type=None, size=None, read_op=None, write_op=None):
-        self.pub_type = pub_type    # the type we expose externally, e.g. 'U8'
-        if priv_type is None:
-            priv_type = pub_type
-        self.priv_type = priv_type  # the internal storage type
-        self.size = size            # bytes on the wire; None == variable length or hard to calc
-        if read_op is None:
-            read_op = 'ChannelUtils.read%s(this, "$name", bb)' % self.pub_type
-        if write_op is None:
-            write_op = 'ChannelUtils.write($name)'
-        self._read_op = read_op
-        self.write_op = write_op
-
-    @property
-    def public_type(self):
-        """ return the public type """
-        return self.pub_type
-
-    def priv(self):
-        """ return the public type """
-        return self.priv_type
-
-    def has_priv(self):
-        """ Is the private type different from the public one?"""
-        return self.pub_type != self.priv_type
-
-    def read_op(self, version=None):
-        if callable(self._read_op):
-            return self._read_op(version)
-        else:
-            return self._read_op
-
-hello_elem_list = JType("List<OFHelloElement>",
-        read_op = 'ChannelUtils.readHelloElementList(bb)',
-        write_op = 'ChannelUtils.writeHelloElementList(bb)'
-        )
-
-u8 =  JType('byte',  size=1, read_op='bb.readByte()',
-        write_op='bb.writeByte($name)')
-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)')
-u64 = JType('U64', 'U64', size=8, read_op='U64.of(bb.readLong())',
-        write_op='bb.writeLong($name.getLong())')
-of_port= JType('OFPort',size=None,
-        read_op=lambda(version): 'OFPort.ofShort(bb.readShort())' if version.int_version < 2 else 'OFPort.ofInt(bb.readInt())',
-        write_op='$name.writeTo(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 - MINIMUM_LENGTH)',
-        write_op = 'ChannelUtils.writeList(this, $name)')
-instructions_list = JType('List<OFInstruction>', size='ChannelUtils.calcListSize($name)',
-        read_op = 'ChannelUtils.readInstructionsList(bb, length - MINIMUM_LENGTH)',
-        write_op = 'ChannelUtils.writeList(this, $name)')
-buckets_list = JType('List<OFBucket>', size='ChannelUtils.calcListSize($name)',
-        read_op = 'ChannelUtils.readBucketList(bb, length - MINIMUM_LENGTH)',
-        write_op = 'ChannelUtils.writeList(this, $name)')
-port_desc_list = JType('List<OFPhysicalPort>', size='ChannelUtils.calcListSize($name)',
-        read_op = 'ChannelUtils.readPhysicalPortList(bb, length - MINIMUM_LENGTH)',
-        write_op = 'ChannelUtils.writeList(this, $name)')
-port_desc = JType('OFPhysicalPort', size='$name.getLength()',
-        read_op = 'ChannelUtils.readPhysicalPort(bb)',
-        write_op = 'ChannelUtils.write(this, $name)')
-packet_queue_list = JType('List<OFPacketQueue>', size='ChannelUtils.calcListSize($name)',
-        read_op = 'ChannelUtils.readPacketQueueList(bb, length - MINIMUM_LENGTH)',
-        write_op = 'ChannelUtils.writeList(this, $name)')
-octets = JType('byte[]', size="length - MINIMUM_LENGTH",
-        read_op = 'ChannelUtils.readBytes(bb, length - MINIMUM_LENGTH)',
-        write_op = 'ChannelUtils.writeBytes(bb, this.$name)')
-of_match = JType('Match', size="$name.getLength()",
-        read_op = 'ChannelUtils.readOFMatch(bb)',
-        write_op = 'ChannelUtils.writeOFMatch(this, $name)')
-flow_mod_cmd = JType('OFFlowModCmd', size="$name.getLength()",
-        read_op = 'ChannelUtils.readOFFlowModCmd(bb)',
-        write_op = 'ChannelUtils.writeOFFlowModCmd(this, $name)')
-mac_addr = JType('MacAddress', 'byte[]', size=6,
-        read_op = 'MacAddress.readFrom(bb)',
-        write_op = 'ChannelUtils.writeBytes(bb, $name)')
-bsn_interface_list = JType("List<OFBsnInterface>",
-        read_op = 'ChannelUtils.readBsnInterfaceList(bb)',
-        write_op = 'ChannelUtils.writeBsnInterfaceList(bb)'
-        )
-meter_band_list = JType("List<OFMeterBand>",
-        read_op = 'ChannelUtils.readMeterBandList(bb)',
-        write_op = 'ChannelUtils.writeMeterBandList(bb, $name)'
-        )
-
-
-
-
-
-default_mtype_to_jtype_convert_map = {
-        'uint8_t' : u8,
-        'uint16_t' : u16,
-        'uint32_t' : u32,
-        'uint64_t' : u64,
-        'uint8_t[1]' : one_byte_array,
-        'uint8_t[2]' : two_byte_array,
-        'uint8_t[3]' : three_byte_array,
-        'uint8_t[4]' : four_byte_array,
-        'uint8_t[5]' : five_byte_array,
-        'uint8_t[6]' : six_byte_array,
-        'uint8_t[7]' : seven_byte_array,
-        'of_port_no_t' : of_port,
-        'of_list_action_t' : actions_list,
-        'of_list_instruction_t' : instructions_list,
-        'of_list_bucket_t': buckets_list,
-        'of_list_port_desc_t' : port_desc_list,
-        'of_list_packet_queue_t' : packet_queue_list,
-        'of_octets_t' : octets,
-        'of_match_t': of_match,
-        'of_fm_cmd_t': flow_mod_cmd,
-        'of_mac_addr_t': mac_addr,
-        'of_port_desc_t': port_desc,
-        'of_list_bsn_interface_t': bsn_interface_list,
-        'of_list_hello_elem_t': hello_elem_list,
-        'of_list_meter_band_t': meter_band_list
-        }
-
-## This is where we drop in special case handling for certain types
-exceptions = {
-        'OFPacketIn': {
-            'data' : octets
-            },
-        }
-
-
-def convert_to_jtype(obj_name, field_name, c_type):
-    """ Convert from a C type ("uint_32") to a java type ("U32")
-    and return a JType object with the size, internal type, and marshalling functions"""
-    if obj_name in exceptions and field_name in exceptions[obj_name]:
-        return exceptions[obj_name][field_name]
-    elif c_type in default_mtype_to_jtype_convert_map:
-        return default_mtype_to_jtype_convert_map[c_type]
-    else:
-        print "WARN: Couldn't find java type conversion for '%s' in %s:%s" % (c_type, obj_name, field_name)
-        jtype = name_c_to_caps_camel(c_type)      # not sure... try to fake it
-        return JType(jtype)
-
-
-def mkdir_p(path):
-    """ Emulates `mkdir -p` """
-    try:
-        os.makedirs(path)
-    except OSError as exc: # Python >2.5
-        if exc.errno == errno.EEXIST:
-            pass
-        else: raise
-
-def copy_file_with_boiler_plate(src_name, dst_name, with_boiler=True):
-    with open("java_gen/pre-written/%s" % src_name, "r") as src:
-        with open(dst_name, "w") as dst:
-            if with_boiler:
-                print_boiler_plate(os.path.basename(dst_name), dst)
-            dst.writelines(src.readlines())
-
-def frob(s, **kwargs):
-    """ Step through string s and for each key in kwargs,
-         replace $key with kwargs[key] in s.
-    """
-    for k,v in kwargs.iteritems():
-        s = s.replace('$%s' % k, v)
-    return s
-
-def copy_prewrite_tree(basedir):
-    """ Recursively copy the directory structure from ./java_gen/pre-write
-       into $basedir"""
-    print "Copying pre-written files into %s" % basedir
-#    subprocess.call("cd java_gen/pre-written && tar cpf - . | ( cd ../../%s && tar xvpf - )" % basedir,
-#            shell=True)
diff --git a/java_gen/msgs.py b/java_gen/msgs.py
deleted file mode 100644
index 3cdef2c..0000000
--- a/java_gen/msgs.py
+++ /dev/null
@@ -1,55 +0,0 @@
-import of_g
-import os
-import pdb
-import re
-
-import loxi_front_end.type_maps as type_maps
-import loxi_utils.loxi_utils as utils
-import py_gen.util as py_utils
-
-import java_gen.java_utils as java_utils
-from java_gen.java_model import *
-ignore_fields = ['version', 'xid', 'length', 'type' ]
-
-protected_fields = ['version', 'length']
-
-
-templates_dir = os.path.join(os.path.dirname(os.path.realpath(__file__)), 'templates')
-
-def render_template(out, name, **context):
-    prefix = '//::(?=[ \t]|$)'
-    utils.render_template(out, name, [templates_dir], context, prefix=prefix)
-
-def create_message_interfaces(message_names, basedir):
-    """ Create the base interfaces for OFMessages"""
-    for msg_name in message_names:
-        msg = JavaOFMessage(msg_name)
-
-        filename = os.path.join(basedir, "%s.java" % msg.interface_name)
-        dirname = os.path.dirname(filename)
-        if not os.path.exists(dirname):
-            os.makedirs(dirname)
-
-        with open(filename, "w") as f:
-            render_template(f, "message_interface.java", msg=msg)
-
-def create_of_type_enum(message_names, basedir):
-    all_versions = [ JavaOFVersion(v) for v in of_g.target_version_list ]
-    messages =  sorted(filter(lambda msg: not msg.is_virtual and not msg.is_extension, [ JavaOFMessage(msg_name) for msg_name in message_names ]), key=lambda msg: msg.wire_type(all_versions[-1]))
-    filename = os.path.join(basedir, "../types/OFType.java")
-    dirname = os.path.dirname(filename)
-    if not os.path.exists(dirname):
-        os.makedirs(dirname)
-    with open(filename, "w") as f:
-        render_template(f, "of_type.java", all_messages=messages, all_versions = all_versions)
-
-def create_message_by_version(message_names, basedir):
-    """ Create the OF Messages for each version that implement the above interfaces"""
-    for msg_name in message_names:
-        msg = JavaOFMessage(msg_name)
-
-        for version in msg.all_versions():
-            filename = os.path.join(basedir, "%s.java" % msg.class_name_for_version(version))
-            with open(filename, "w") as f:
-                   render_template(f, "message_class.java", msg=msg, version=version,
-                            impl_class=msg.class_name_for_version(version))
diff --git a/java_gen/pre-written/.classpath b/java_gen/pre-written/.classpath
new file mode 100644
index 0000000..b6bc6ad
--- /dev/null
+++ b/java_gen/pre-written/.classpath
@@ -0,0 +1,7 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<classpath>
+	<classpathentry kind="src" path="src/main/java"/>
+	<classpathentry kind="lib" path="lib/netty-3.2.6.Final.jar"/>
+	<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER"/>
+	<classpathentry kind="output" path="bin"/>
+</classpath>
diff --git a/java_gen/pre-written/.project b/java_gen/pre-written/.project
new file mode 100644
index 0000000..b347bd6
--- /dev/null
+++ b/java_gen/pre-written/.project
@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<projectDescription>
+	<name>openflowj-loxi</name>
+	<comment></comment>
+	<projects>
+	</projects>
+	<buildSpec>
+		<buildCommand>
+			<name>org.eclipse.jdt.core.javabuilder</name>
+			<arguments>
+			</arguments>
+		</buildCommand>
+	</buildSpec>
+	<natures>
+		<nature>org.eclipse.jdt.core.javanature</nature>
+	</natures>
+</projectDescription>
diff --git a/java_gen/pre-written/lib/.gitignore b/java_gen/pre-written/lib/.gitignore
deleted file mode 100644
index b4cb1f8..0000000
--- a/java_gen/pre-written/lib/.gitignore
+++ /dev/null
@@ -1 +0,0 @@
-netty-3.2.6.Final.jar
diff --git a/java_gen/pre-written/pom.xml b/java_gen/pre-written/pom.xml
new file mode 100644
index 0000000..d01d797
--- /dev/null
+++ b/java_gen/pre-written/pom.xml
@@ -0,0 +1,55 @@
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <groupId>org.openflow</groupId>
+    <artifactId>openflowj</artifactId>
+    <version>2.0-SNAPSHOT</version>
+    <packaging>jar</packaging>
+
+    <name>Loxi-Generated OpenFlow/J</name>
+    <url>http://www.projectfloodlight.org/projects/</url>
+
+    <properties>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+    </properties>
+
+    <dependencies>
+        <dependency>
+            <groupId>junit</groupId>
+            <artifactId>junit</artifactId>
+            <version>4.8.2</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.jboss.netty</groupId>
+            <artifactId>netty</artifactId>
+            <version>3.2.9.Final</version>
+        </dependency>
+        <dependency>
+            <groupId>com.google.guava</groupId>
+            <artifactId>guava</artifactId>
+            <version>14.0.1</version>
+        </dependency>
+    </dependencies>
+    <build>
+    <plugins>
+    <plugin>
+        <groupId>org.codehaus.mojo</groupId>
+        <artifactId>build-helper-maven-plugin</artifactId>
+        <version>1.8</version>
+        <executions>
+            <execution>
+                <phase>generate-sources</phase>
+                <goals><goal>add-source</goal></goals>
+                <configuration>
+                    <sources>
+                        <source>../../java_gen/pre-written/src/main/java/</source>
+                    </sources>
+                </configuration>
+            </execution>
+        </executions>
+    </plugin>
+</plugins>
+</build>
+</project>
diff --git a/java_gen/pre-written/src/main/java/org/openflow/protocol/OFAbstractMessage.java b/java_gen/pre-written/src/main/java/org/openflow/protocol/OFAbstractMessage.java
deleted file mode 100644
index bc2218f..0000000
--- a/java_gen/pre-written/src/main/java/org/openflow/protocol/OFAbstractMessage.java
+++ /dev/null
@@ -1,83 +0,0 @@
-/* Copyright 2013, Big Switch Networks, Inc.
- *
- * LoxiGen is licensed under the Eclipse Public License, version 1.0 (EPL), with
- * the following special exception:
- *
- * LOXI Exception
- *
- * As a special exception to the terms of the EPL, you may distribute libraries
- * generated by LoxiGen (LoxiGen Libraries) under the terms of your choice, provided
- * that copyright and licensing notices generated by LoxiGen are not altered or removed
- * from the LoxiGen Libraries and the notice provided below is (i) included in
- * the LoxiGen Libraries, if distributed in source code form and (ii) included in any
- * documentation for the LoxiGen Libraries, if distributed in binary form.
- *
- * Notice: "Copyright 2013, Big Switch Networks, Inc. This library was generated by the LoxiGen Compiler."
- *
- * You may not use this file except in compliance with the EPL or LOXI Exception. You may obtain
- * a copy of the EPL at:
- *
- * http://www.eclipse.org/legal/epl-v10.html
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
- * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
- * EPL for the specific language governing permissions and limitations
- * under the EPL.
- */
-package org.openflow.protocol;
-
-/**
- * The base interface for all OpenFlow message objects
- */
-
-import org.openflow.types.OFType;
-
-abstract public class OFAbstractMessage implements OFObject {
-    private final OFVersion version;
-    private final OFType type;
-    private int xid;
-
-    public static int MINIMUM_SIZE = 8;
-
-    public OFAbstractMessage(final OFVersion version, final OFType type) {
-        this.version = version;
-        this.type = type;
-    }
-
-    /**
-     * Return the wire format version of this message, e.g., 0x01
-     */
-    OFVersion getVersion() {
-        return version;
-    }
-
-    /**
-     * @return the transction ID for this message
-     */
-    int getXid() {
-        return xid;
-    }
-
-    /**
-     * @param newXid
-     *            Set this transaction ID for this message
-     */
-    void setXid(final int xid) {
-        this.xid = xid;
-    }
-
-    /**
-     * The type that is returned here is agnostic to the underlying wire format
-     *
-     * @return the type of OpenFlow message.
-     */
-    OFType getType() {
-        return type;
-    }
-
-    @Override
-    public int getLength() {
-        return MINIMUM_SIZE;
-    }
-}
diff --git a/java_gen/pre-written/src/main/java/org/openflow/protocol/OFBsnVportQInQT.java b/java_gen/pre-written/src/main/java/org/openflow/protocol/OFBsnVportQInQT.java
new file mode 100644
index 0000000..c5b884e
--- /dev/null
+++ b/java_gen/pre-written/src/main/java/org/openflow/protocol/OFBsnVportQInQT.java
@@ -0,0 +1,5 @@
+package org.openflow.protocol;
+
+public class OFBsnVportQInQT {
+
+}
diff --git a/java_gen/pre-written/src/main/java/org/openflow/protocol/OFFlowMod.java b/java_gen/pre-written/src/main/java/org/openflow/protocol/OFFlowMod.java
new file mode 100644
index 0000000..06d8049
--- /dev/null
+++ b/java_gen/pre-written/src/main/java/org/openflow/protocol/OFFlowMod.java
@@ -0,0 +1,8 @@
+package org.openflow.protocol;
+
+public interface OFFlowMod extends OFMessage {
+
+    public interface Builder extends OFMessage.Builder {
+
+    }
+}
diff --git a/java_gen/pre-written/src/main/java/org/openflow/protocol/OFMatchBmap.java b/java_gen/pre-written/src/main/java/org/openflow/protocol/OFMatchBmap.java
new file mode 100644
index 0000000..6e4dc5b
--- /dev/null
+++ b/java_gen/pre-written/src/main/java/org/openflow/protocol/OFMatchBmap.java
@@ -0,0 +1,5 @@
+package org.openflow.protocol;
+
+public class OFMatchBmap {
+
+}
diff --git a/java_gen/pre-written/src/main/java/org/openflow/protocol/OFMessage.java b/java_gen/pre-written/src/main/java/org/openflow/protocol/OFMessage.java
index 4f31741..c1e4456 100644
--- a/java_gen/pre-written/src/main/java/org/openflow/protocol/OFMessage.java
+++ b/java_gen/pre-written/src/main/java/org/openflow/protocol/OFMessage.java
@@ -1,13 +1,13 @@
 package org.openflow.protocol;
 
-import org.openflow.types.OFType;
-
 public interface OFMessage {
     int getXid();
 
-    boolean isXidSet();
-
     OFType getType();
 
     OFVersion getVersion();
+
+    interface Builder {
+
+    }
 }
diff --git a/java_gen/pre-written/src/main/java/org/openflow/protocol/OFMessageReader.java b/java_gen/pre-written/src/main/java/org/openflow/protocol/OFMessageReader.java
index 24c3314..3f34d9b 100644
--- a/java_gen/pre-written/src/main/java/org/openflow/protocol/OFMessageReader.java
+++ b/java_gen/pre-written/src/main/java/org/openflow/protocol/OFMessageReader.java
@@ -3,6 +3,6 @@
 import org.jboss.netty.buffer.ChannelBuffer;
 import org.openflow.exceptions.OFParseError;
 
-public interface OFMessageReader<T extends OFMessage> {
+public interface OFMessageReader<T> {
     T readFrom(ChannelBuffer bb) throws OFParseError;
 }
diff --git a/java_gen/pre-written/src/main/java/org/openflow/protocol/OFMessageWriter.java b/java_gen/pre-written/src/main/java/org/openflow/protocol/OFMessageWriter.java
new file mode 100644
index 0000000..84e5507
--- /dev/null
+++ b/java_gen/pre-written/src/main/java/org/openflow/protocol/OFMessageWriter.java
@@ -0,0 +1,8 @@
+package org.openflow.protocol;
+
+import org.jboss.netty.buffer.ChannelBuffer;
+import org.openflow.exceptions.OFParseError;
+
+public interface OFMessageWriter<T> {
+    public int write(ChannelBuffer bb, T message) throws OFParseError;
+}
diff --git a/java_gen/pre-written/src/main/java/org/openflow/protocol/OFObject.java b/java_gen/pre-written/src/main/java/org/openflow/protocol/OFObject.java
index 21a4607..4a7557f 100644
--- a/java_gen/pre-written/src/main/java/org/openflow/protocol/OFObject.java
+++ b/java_gen/pre-written/src/main/java/org/openflow/protocol/OFObject.java
@@ -1,5 +1,7 @@
 package org.openflow.protocol;
 
+import org.jboss.netty.buffer.ChannelBuffer;
+
 /**
  *  Base interface of all OpenFlow objects (e.g., messages, actions, stats, etc.)
  *
@@ -10,26 +12,8 @@
  *  malformed packets, for example, for negative testing.
  */
 
-import org.jboss.netty.buffer.ChannelBuffer;
-import org.openflow.exceptions.OFParseError;
-import org.openflow.exceptions.OFShortWrite;
 
 public interface OFObject {
-    /**
-     * Return a number equal or greater than zero (and currently in OF less than
-     * 65536)
-     *
-     * @return the number of bytes this object will represent on the wire
-     */
-    public int getLength();
-
-    /**
-     * Automatically calculate any lengths and write an openflow object into the
-     * byte buffer.
-     *
-     * @param bb
-     *            A valid byte buffer with sufficient capacity to hold this
-     *            object/
-     */
-    public void writeTo(ChannelBuffer bb) throws OFParseError, OFShortWrite;
+    void writeTo(ChannelBuffer bb);
+    int getLength();
 }
diff --git a/java_gen/pre-written/src/main/java/org/openflow/protocol/OFTableFeature.java b/java_gen/pre-written/src/main/java/org/openflow/protocol/OFTableFeature.java
new file mode 100644
index 0000000..114f638
--- /dev/null
+++ b/java_gen/pre-written/src/main/java/org/openflow/protocol/OFTableFeature.java
@@ -0,0 +1,5 @@
+package org.openflow.protocol;
+
+public class OFTableFeature {
+    // FIXME implement
+}
diff --git a/java_gen/pre-written/src/main/java/org/openflow/protocol/OFVersion.java b/java_gen/pre-written/src/main/java/org/openflow/protocol/OFVersion.java
index afc0393..7241647 100644
--- a/java_gen/pre-written/src/main/java/org/openflow/protocol/OFVersion.java
+++ b/java_gen/pre-written/src/main/java/org/openflow/protocol/OFVersion.java
@@ -3,7 +3,7 @@
 public enum OFVersion {
     OF_10(1), OF_11(2), OF_12(3), OF_13(4);
 
-    private final int wireVersion;
+    public final int wireVersion;
 
     OFVersion(final int wireVersion) {
         this.wireVersion = wireVersion;
diff --git a/java_gen/pre-written/src/main/java/org/openflow/protocol/Wildcards.java b/java_gen/pre-written/src/main/java/org/openflow/protocol/Wildcards.java
new file mode 100644
index 0000000..25b2c21
--- /dev/null
+++ b/java_gen/pre-written/src/main/java/org/openflow/protocol/Wildcards.java
@@ -0,0 +1,5 @@
+package org.openflow.protocol;
+
+public class Wildcards {
+
+}
diff --git a/java_gen/pre-written/src/main/java/org/openflow/protocol/XidGenerator.java b/java_gen/pre-written/src/main/java/org/openflow/protocol/XidGenerator.java
new file mode 100644
index 0000000..0819ac2
--- /dev/null
+++ b/java_gen/pre-written/src/main/java/org/openflow/protocol/XidGenerator.java
@@ -0,0 +1,5 @@
+package org.openflow.protocol;
+
+public interface XidGenerator {
+    int nextXid();
+}
diff --git a/java_gen/pre-written/src/main/java/org/openflow/protocol/actions/OFAction.java b/java_gen/pre-written/src/main/java/org/openflow/protocol/actions/OFAction.java
deleted file mode 100644
index f01f8fe..0000000
--- a/java_gen/pre-written/src/main/java/org/openflow/protocol/actions/OFAction.java
+++ /dev/null
@@ -1,7 +0,0 @@
-package org.openflow.protocol.actions;
-
-import org.openflow.protocol.OFObject;
-
-public interface OFAction extends OFObject {
-
-}
diff --git a/java_gen/pre-written/src/main/java/org/openflow/protocol/instructions/OFInstruction.java b/java_gen/pre-written/src/main/java/org/openflow/protocol/instructions/OFInstruction.java
deleted file mode 100644
index 8af305c..0000000
--- a/java_gen/pre-written/src/main/java/org/openflow/protocol/instructions/OFInstruction.java
+++ /dev/null
@@ -1,7 +0,0 @@
-package org.openflow.protocol.instructions;
-
-import org.openflow.protocol.OFObject;
-
-public interface OFInstruction extends OFObject {
-
-}
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 19ced8f..f00e1b4 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
@@ -1,8 +1,6 @@
 package org.openflow.protocol.match;
 
 import org.jboss.netty.buffer.ChannelBuffer;
-import org.openflow.exceptions.OFParseError;
-import org.openflow.exceptions.OFShortWrite;
 import org.openflow.protocol.types.IpDscp;
 import org.openflow.types.EthType;
 import org.openflow.types.IPv4;
@@ -157,7 +155,7 @@
     }
 
     @Override
-    public void writeTo(final ChannelBuffer bb) throws OFParseError, OFShortWrite {
+    public void writeTo(final ChannelBuffer bb) {
         // TODO Auto-generated method stub
 
     }
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 b4eb8cf..0583d6f 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
@@ -1,9 +1,6 @@
 package org.openflow.types;
 
 import org.jboss.netty.buffer.ChannelBuffer;
-import org.openflow.exceptions.OFParseError;
-import org.openflow.exceptions.OFShortRead;
-import org.openflow.exceptions.OFShortWrite;
 import org.openflow.protocol.OFObject;
 
 /**
@@ -85,12 +82,12 @@
         return LENGTH;
     }
 
-    public static IPv4 readFrom(final ChannelBuffer bb) throws OFParseError, OFShortRead {
+    public static IPv4 readFrom(final ChannelBuffer bb) {
         return IPv4.of(bb.readInt());
     }
 
     @Override
-    public void writeTo(final ChannelBuffer bb) throws OFParseError, OFShortWrite {
+    public void writeTo(final ChannelBuffer bb) {
         bb.writeInt(rawValue);
     }
 
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 5f51665..19002d9 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
@@ -4,8 +4,6 @@
 
 import org.jboss.netty.buffer.ChannelBuffer;
 import org.openflow.exceptions.OFParseError;
-import org.openflow.exceptions.OFShortRead;
-import org.openflow.exceptions.OFShortWrite;
 import org.openflow.protocol.OFObject;
 
 /**
@@ -161,12 +159,12 @@
         return LENGTH;
     }
 
-    public static IPv6 readFrom(final ChannelBuffer bb) throws OFParseError, OFShortRead {
+    public static IPv6 readFrom(final ChannelBuffer bb) throws OFParseError {
         return IPv6.of(bb.readLong(), bb.readLong());
     }
 
     @Override
-    public void writeTo(final ChannelBuffer bb) throws OFParseError, OFShortWrite {
+    public void writeTo(final ChannelBuffer bb) {
         bb.writeLong(raw1);
         bb.writeLong(raw2);
     }
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 4ce19ab..8806bb3 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
@@ -2,7 +2,6 @@
 
 import org.jboss.netty.buffer.ChannelBuffer;
 import org.openflow.exceptions.OFParseError;
-import org.openflow.exceptions.OFShortWrite;
 import org.openflow.protocol.OFObject;
 import org.openflow.util.HexString;
 
@@ -84,7 +83,7 @@
     }
 
     @Override
-    public void writeTo(final ChannelBuffer bb) throws OFParseError, OFShortWrite {
+    public void writeTo(final ChannelBuffer bb) {
         bb.writeInt((int) (rawValue >> 16));
         bb.writeShort((int) rawValue & 0xFFFF);
     }
diff --git a/java_gen/pre-written/src/main/java/org/openflow/types/OFBsnInterface.java b/java_gen/pre-written/src/main/java/org/openflow/types/OFBsnInterface.java
deleted file mode 100644
index d0afb56..0000000
--- a/java_gen/pre-written/src/main/java/org/openflow/types/OFBsnInterface.java
+++ /dev/null
@@ -1,5 +0,0 @@
-package org.openflow.types;
-
-public interface OFBsnInterface {
-
-}
diff --git a/java_gen/pre-written/src/main/java/org/openflow/types/OFBucket.java b/java_gen/pre-written/src/main/java/org/openflow/types/OFBucket.java
deleted file mode 100644
index 47b403b..0000000
--- a/java_gen/pre-written/src/main/java/org/openflow/types/OFBucket.java
+++ /dev/null
@@ -1,22 +0,0 @@
-package org.openflow.types;
-
-import org.jboss.netty.buffer.ChannelBuffer;
-import org.openflow.exceptions.OFParseError;
-import org.openflow.exceptions.OFShortWrite;
-import org.openflow.protocol.OFObject;
-
-public class OFBucket implements OFObject {
-
-    @Override
-    public int getLength() {
-        // TODO Auto-generated method stub
-        return 0;
-    }
-
-    @Override
-    public void writeTo(final ChannelBuffer bb) throws OFParseError, OFShortWrite {
-        // TODO Auto-generated method stub
-
-    }
-
-}
diff --git a/java_gen/pre-written/src/main/java/org/openflow/types/OFPacketQueue.java b/java_gen/pre-written/src/main/java/org/openflow/types/OFPacketQueue.java
deleted file mode 100644
index d74906f..0000000
--- a/java_gen/pre-written/src/main/java/org/openflow/types/OFPacketQueue.java
+++ /dev/null
@@ -1,22 +0,0 @@
-package org.openflow.types;
-
-import org.jboss.netty.buffer.ChannelBuffer;
-import org.openflow.exceptions.OFParseError;
-import org.openflow.exceptions.OFShortWrite;
-import org.openflow.protocol.OFObject;
-
-public class OFPacketQueue implements OFObject {
-
-    @Override
-    public int getLength() {
-        // TODO Auto-generated method stub
-        return 0;
-    }
-
-    @Override
-    public void writeTo(final ChannelBuffer bb) throws OFParseError, OFShortWrite {
-        // TODO Auto-generated method stub
-
-    }
-
-}
diff --git a/java_gen/pre-written/src/main/java/org/openflow/types/U64.java b/java_gen/pre-written/src/main/java/org/openflow/types/U64.java
index 211c3ea..c0cd475 100644
--- a/java_gen/pre-written/src/main/java/org/openflow/types/U64.java
+++ b/java_gen/pre-written/src/main/java/org/openflow/types/U64.java
@@ -20,8 +20,7 @@
 import java.math.BigInteger;
 
 public class U64 {
-    private final static BigInteger TWO_POWER_64 = BigInteger.valueOf(Long.MAX_VALUE).add(
-            BigInteger.valueOf(1));
+    private static final long UNSIGNED_MASK = 0x7fffffffffffffffL;
 
     private final long raw;
 
@@ -38,8 +37,11 @@
     }
 
     public BigInteger getBigInteger() {
-        return raw >= 0 ? BigInteger.valueOf(raw) : TWO_POWER_64.add(BigInteger
-                .valueOf(raw));
+        BigInteger bigInt = BigInteger.valueOf(raw & UNSIGNED_MASK);
+        if (raw < 0) {
+          bigInt = bigInt.setBit(Long.SIZE - 1);
+        }
+        return bigInt;
     }
 
     @Override
@@ -47,8 +49,12 @@
         return getBigInteger().toString();
     }
 
-    public static BigInteger f(final long i) {
-        return new BigInteger(Long.toBinaryString(i), 2);
+    public static BigInteger f(final long value) {
+        BigInteger bigInt = BigInteger.valueOf(value & UNSIGNED_MASK);
+        if (value < 0) {
+          bigInt = bigInt.setBit(Long.SIZE - 1);
+        }
+        return bigInt;
     }
 
     public static long t(final BigInteger l) {
diff --git a/java_gen/pre-written/src/main/java/org/openflow/util/ChannelUtils.java b/java_gen/pre-written/src/main/java/org/openflow/util/ChannelUtils.java
index e8eeebd..dab6ff2 100644
--- a/java_gen/pre-written/src/main/java/org/openflow/util/ChannelUtils.java
+++ b/java_gen/pre-written/src/main/java/org/openflow/util/ChannelUtils.java
@@ -3,17 +3,32 @@
 import java.util.List;
 
 import org.jboss.netty.buffer.ChannelBuffer;
-import org.openflow.protocol.actions.OFAction;
-import org.openflow.protocol.instructions.OFInstruction;
+import org.openflow.protocol.OFBsnInterface;
+import org.openflow.protocol.OFBsnVportQInQ;
+import org.openflow.protocol.OFBsnVportQInQT;
+import org.openflow.protocol.OFBucket;
+import org.openflow.protocol.OFFlowStatsEntry;
+import org.openflow.protocol.OFGroupDescStatsEntry;
+import org.openflow.protocol.OFGroupStatsEntry;
+import org.openflow.protocol.OFHelloElem;
+import org.openflow.protocol.OFMeterFeatures;
+import org.openflow.protocol.OFMeterStats;
+import org.openflow.protocol.OFPacketQueue;
+import org.openflow.protocol.OFPortStatsEntry;
+import org.openflow.protocol.OFQueueStatsEntry;
+import org.openflow.protocol.OFTableFeature;
+import org.openflow.protocol.OFTableFeatures;
+import org.openflow.protocol.OFTableStatsEntry;
+import org.openflow.protocol.action.OFAction;
+import org.openflow.protocol.instruction.OFInstruction;
 import org.openflow.protocol.match.Match;
-import org.openflow.types.OFBsnInterface;
-import org.openflow.types.OFBucket;
 import org.openflow.types.OFFlowModCmd;
 import org.openflow.types.OFHelloElement;
 import org.openflow.types.OFMeterBand;
-import org.openflow.types.OFPacketQueue;
 import org.openflow.types.OFPhysicalPort;
 
+import com.google.common.base.Charsets;
+
 /**
  * Collection of helper functions for reading and writing into ChannelBuffers
  *
@@ -90,4 +105,212 @@
         return null;
     }
 
+    public static void writeOFMatch(ChannelBuffer bb, Match match) {
+        // TODO Auto-generated method stub
+
+    }
+
+    public static void writeList(ChannelBuffer bb, List<?> ports) {
+        // TODO Auto-generated method stub
+
+    }
+
+    public static void writeOFFlowModCmd(ChannelBuffer bb, OFFlowModCmd command) {
+        // TODO Auto-generated method stub
+
+    }
+
+    public static String readFixedLengthString(ChannelBuffer bb, int length) {
+        byte[] dst = new byte[length];
+        bb.readBytes(dst, 0, length);
+        return new String(dst, Charsets.US_ASCII);
+    }
+
+    public static void writeFixedLengthString(ChannelBuffer bb, String string, int length) {
+        int l = string.length();
+        if(l > length) {
+            throw new IllegalArgumentException("Error writing string: length="+l+" > max Length="+length);
+        }
+        bb.writeBytes(string.getBytes(Charsets.US_ASCII));
+        if(l < length) {
+            bb.writeZero(length - l);
+        }
+    }
+
+    public static void writeBsnInterfaceList(ChannelBuffer bb, List<OFBsnInterface> interfaces) {
+        // TODO Auto-generated method stub
+
+    }
+
+    public static void writeTableFeatureList(ChannelBuffer bb,
+            List<OFTableFeature> entries) {
+        // TODO Auto-generated method stub
+
+    }
+
+    public static void writeBsnInterface(ChannelBuffer bb,
+            List<OFBsnInterface> interfaces) {
+        // TODO Auto-generated method stub
+
+    }
+
+    public static void writeFlowStatsEntry(ChannelBuffer bb,
+            List<OFFlowStatsEntry> entries) {
+        // TODO Auto-generated method stub
+
+    }
+
+    public static List<OFFlowStatsEntry> readFlowStatsEntry(ChannelBuffer bb) {
+        // TODO Auto-generated method stub
+        return null;
+    }
+
+    public static void writeTableStatsEntryList(ChannelBuffer bb,
+            List<OFTableStatsEntry> entries) {
+        // TODO Auto-generated method stub
+
+    }
+
+    public static List<OFTableStatsEntry> readTableStatsEntryList(
+            ChannelBuffer bb) {
+        // TODO Auto-generated method stub
+        return null;
+    }
+
+    public static List<OFFlowStatsEntry> readFlowStatsEntryList(ChannelBuffer bb) {
+        // TODO Auto-generated method stub
+        return null;
+    }
+
+    public static void writeFlowStatsEntryList(ChannelBuffer bb,
+            List<OFFlowStatsEntry> entries) {
+        // TODO Auto-generated method stub
+
+    }
+
+    public static void writeGroupDescStatsEntryList(ChannelBuffer bb,
+            List<OFGroupDescStatsEntry> entries) {
+        // TODO Auto-generated method stub
+
+    }
+
+    public static List<OFGroupDescStatsEntry> readGroupDescStatsEntryList(
+            ChannelBuffer bb) {
+        // TODO Auto-generated method stub
+        return null;
+    }
+
+    public static void writeOFBsnVportQInQT(ChannelBuffer bb,
+            OFBsnVportQInQT vport) {
+        // TODO Auto-generated method stub
+
+    }
+
+    public static void writeMeterBandList(ChannelBuffer bb,
+            List<OFMeterBand> entries) {
+        // TODO Auto-generated method stub
+
+    }
+
+    public static int writeActionsList(ChannelBuffer bb, List<OFAction> actions) {
+        // TODO Auto-generated method stub
+        return 0;
+    }
+
+    public static OFBsnVportQInQ readOFBsnVportQInQ(ChannelBuffer bb) {
+        // TODO Auto-generated method stub
+        return null;
+    }
+
+    public static void writePortStatsEntryList(ChannelBuffer bb,
+            List<OFPortStatsEntry> entries) {
+        // TODO Auto-generated method stub
+
+    }
+
+    public static void write(ChannelBuffer bb, OFPhysicalPort desc) {
+        // TODO Auto-generated method stub
+
+    }
+
+    public static List<OFPortStatsEntry> readPortStatsEntryList(ChannelBuffer bb) {
+        // TODO Auto-generated method stub
+        return null;
+    }
+
+    public static void writeOFBsnVportQInQ(ChannelBuffer bb,
+            OFBsnVportQInQ vport) {
+        // TODO Auto-generated method stub
+
+    }
+
+    public static List<OFHelloElem> readHelloElemList(ChannelBuffer bb) {
+        // TODO Auto-generated method stub
+        return null;
+    }
+
+    public static void writeHelloElemList(ChannelBuffer bb,
+            List<OFHelloElem> elements) {
+        // TODO Auto-generated method stub
+
+    }
+
+    public static List<OFGroupStatsEntry> readGroupStatsEntryList(
+            ChannelBuffer bb) {
+        // TODO Auto-generated method stub
+        return null;
+    }
+
+    public static void writeGroupStatsEntryList(ChannelBuffer bb,
+            List<OFGroupStatsEntry> entries) {
+        // TODO Auto-generated method stub
+
+    }
+
+    public static List<OFQueueStatsEntry> readQueueStatsEntryList(
+            ChannelBuffer bb) {
+        // TODO Auto-generated method stub
+        return null;
+    }
+
+    public static void writeQueueStatsEntryList(ChannelBuffer bb,
+            List<OFQueueStatsEntry> entries) {
+        // TODO Auto-generated method stub
+
+    }
+
+    public static OFMeterFeatures readOFMeterFeatures(ChannelBuffer bb) {
+        // TODO Auto-generated method stub
+        return null;
+    }
+
+    public static void writeOFMeterFeatures(ChannelBuffer bb,
+            OFMeterFeatures features) {
+        // TODO Auto-generated method stub
+
+    }
+
+    public static List<OFMeterStats> readMeterStatsList(ChannelBuffer bb) {
+        // TODO Auto-generated method stub
+        return null;
+    }
+
+    public static void writeMeterStatsList(ChannelBuffer bb,
+            List<OFMeterStats> entries) {
+        // TODO Auto-generated method stub
+
+    }
+
+    public static List<OFTableFeatures> readTableFeaturesList(ChannelBuffer bb) {
+        // TODO Auto-generated method stub
+        return null;
+    }
+
+    public static void writeTableFeaturesList(ChannelBuffer bb,
+            List<OFTableFeatures> entries) {
+        // TODO Auto-generated method stub
+
+    }
+
+
 }
diff --git a/java_gen/pre-written/src/main/java/org/openflow/util/LengthCountingPseudoChannelBuffer.java b/java_gen/pre-written/src/main/java/org/openflow/util/LengthCountingPseudoChannelBuffer.java
new file mode 100644
index 0000000..bd0adce
--- /dev/null
+++ b/java_gen/pre-written/src/main/java/org/openflow/util/LengthCountingPseudoChannelBuffer.java
@@ -0,0 +1,673 @@
+package org.openflow.util;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.nio.ByteBuffer;
+import java.nio.ByteOrder;
+import java.nio.channels.GatheringByteChannel;
+import java.nio.channels.ScatteringByteChannel;
+import java.nio.charset.Charset;
+
+import org.jboss.netty.buffer.ChannelBuffer;
+import org.jboss.netty.buffer.ChannelBufferFactory;
+import org.jboss.netty.buffer.ChannelBufferIndexFinder;
+
+public class LengthCountingPseudoChannelBuffer implements ChannelBuffer {
+
+    int writerIndex = 0;
+    private int markedWriterIndex;
+
+    @Override
+    public ChannelBufferFactory factory() {
+        return null;
+    }
+
+    @Override
+    public int capacity() {
+        return Integer.MAX_VALUE;
+    }
+
+    @Override
+    public ByteOrder order() {
+        return ByteOrder.BIG_ENDIAN;
+    }
+
+    @Override
+    public boolean isDirect() {
+        return true;
+    }
+
+    @Override
+    public int readerIndex() {
+        return 0;
+    }
+
+    @Override
+    public void readerIndex(int readerIndex) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public int writerIndex() {
+        return writerIndex;
+    }
+
+    @Override
+    public void writerIndex(int writerIndex) {
+        this.writerIndex = writerIndex;
+    }
+
+    @Override
+    public void setIndex(int readerIndex, int writerIndex) {
+        if(readerIndex != 0)
+            throw new UnsupportedOperationException();
+        this.writerIndex = writerIndex;
+    }
+
+    @Override
+    public int readableBytes() {
+        return writerIndex;
+    }
+
+    @Override
+    public int writableBytes() {
+        return Integer.MAX_VALUE - writerIndex;
+    }
+
+    @Override
+    public boolean readable() {
+        return writerIndex > 0;
+    }
+
+    @Override
+    public boolean writable() {
+        return writerIndex < Integer.MAX_VALUE;
+    }
+
+    @Override
+    public void clear() {
+        writerIndex = 0;
+
+    }
+
+    @Override
+    public void markReaderIndex() {
+    }
+
+    @Override
+    public void resetReaderIndex() {
+    }
+
+    @Override
+    public void markWriterIndex() {
+        markedWriterIndex = writerIndex;
+    }
+
+    @Override
+    public void resetWriterIndex() {
+        writerIndex = markedWriterIndex;
+    }
+
+    @Override
+    public void discardReadBytes() {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public void ensureWritableBytes(int writableBytes) {
+        if(!((Integer.MAX_VALUE - writableBytes) > writerIndex))
+            throw new IllegalStateException();
+    }
+
+    @Override
+    public byte getByte(int index) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public short getUnsignedByte(int index) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public short getShort(int index) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public int getUnsignedShort(int index) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public int getMedium(int index) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public int getUnsignedMedium(int index) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public int getInt(int index) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public long getUnsignedInt(int index) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public long getLong(int index) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public char getChar(int index) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public float getFloat(int index) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public double getDouble(int index) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public void getBytes(int index, ChannelBuffer dst) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public void getBytes(int index, ChannelBuffer dst, int length) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public void getBytes(int index, ChannelBuffer dst, int dstIndex, int length) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public void getBytes(int index, byte[] dst) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public void getBytes(int index, byte[] dst, int dstIndex, int length) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public void getBytes(int index, ByteBuffer dst) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public void getBytes(int index, OutputStream out, int length)
+            throws IOException {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public int getBytes(int index, GatheringByteChannel out, int length)
+            throws IOException {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public void setByte(int index, int value) {
+    }
+
+    @Override
+    public void setShort(int index, int value) {
+    }
+
+    @Override
+    public void setMedium(int index, int value) {
+    }
+
+    @Override
+    public void setInt(int index, int value) {
+    }
+
+    @Override
+    public void setLong(int index, long value) {
+    }
+
+    @Override
+    public void setChar(int index, int value) {
+    }
+
+    @Override
+    public void setFloat(int index, float value) {
+    }
+
+    @Override
+    public void setDouble(int index, double value) {
+    }
+
+    @Override
+    public void setBytes(int index, ChannelBuffer src) {
+    }
+
+    @Override
+    public void setBytes(int index, ChannelBuffer src, int length) {
+    }
+
+    @Override
+    public void setBytes(int index, ChannelBuffer src, int srcIndex, int length) {
+    }
+
+    @Override
+    public void setBytes(int index, byte[] src) {
+    }
+
+    @Override
+    public void setBytes(int index, byte[] src, int srcIndex, int length) {
+    }
+
+    @Override
+    public void setBytes(int index, ByteBuffer src) {
+
+    }
+
+    @Override
+    public int setBytes(int index, InputStream in, int length)
+            throws IOException {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public int setBytes(int index, ScatteringByteChannel in, int length)
+            throws IOException {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public void setZero(int index, int length) {
+    }
+
+    @Override
+    public byte readByte() {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public short readUnsignedByte() {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public short readShort() {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public int readUnsignedShort() {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public int readMedium() {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public int readUnsignedMedium() {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public int readInt() {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public long readUnsignedInt() {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public long readLong() {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public char readChar() {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public float readFloat() {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public double readDouble() {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public ChannelBuffer readBytes(int length) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    @Deprecated
+    public ChannelBuffer readBytes(ChannelBufferIndexFinder indexFinder) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public ChannelBuffer readSlice(int length) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    @Deprecated
+    public
+    ChannelBuffer readSlice(ChannelBufferIndexFinder indexFinder) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public void readBytes(ChannelBuffer dst) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public void readBytes(ChannelBuffer dst, int length) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public void readBytes(ChannelBuffer dst, int dstIndex, int length) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public void readBytes(byte[] dst) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public void readBytes(byte[] dst, int dstIndex, int length) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public void readBytes(ByteBuffer dst) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public void readBytes(OutputStream out, int length) throws IOException {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public int readBytes(GatheringByteChannel out, int length)
+            throws IOException {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public void skipBytes(int length) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    @Deprecated
+    public int skipBytes(ChannelBufferIndexFinder indexFinder) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public void writeByte(int value) {
+        writerIndex++;
+    }
+
+    @Override
+    public void writeShort(int value) {
+    writerIndex += 2;
+}
+
+@Override
+public void writeMedium(int value) {
+    writerIndex += 3;
+}
+
+@Override
+public void writeInt(int value) {
+    writerIndex += 4;
+}
+
+@Override
+public void writeLong(long value) {
+    writerIndex += 8;
+}
+
+
+    @Override
+    public void writeChar(int value) {
+        writeShort(value);
+    }
+
+    @Override
+    public void writeFloat(float value) {
+        writeInt(Float.floatToIntBits(value));
+    }
+
+    @Override
+    public void writeDouble(double value) {
+        writeLong(Double.doubleToLongBits(value));
+
+    }
+
+    @Override
+    public void writeBytes(ChannelBuffer src) {
+        writerIndex += src.readableBytes();
+
+    }
+
+    @Override
+    public void writeBytes(ChannelBuffer src, int length) {
+        writerIndex += src.readableBytes();
+
+    }
+
+    @Override
+    public void writeBytes(ChannelBuffer src, int srcIndex, int length) {
+        writerIndex += length;
+    }
+
+    @Override
+    public void writeBytes(byte[] src) {
+        writerIndex += src.length;
+
+    }
+
+    @Override
+    public void writeBytes(byte[] src, int srcIndex, int length) {
+        writerIndex += length;
+    }
+
+    @Override
+    public void writeBytes(ByteBuffer src) {
+        writerIndex += src.remaining();
+
+    }
+
+    @Override
+    public int writeBytes(InputStream in, int length) throws IOException {
+        writerIndex += length;
+        return length;
+    }
+
+    @Override
+    public int writeBytes(ScatteringByteChannel in, int length)
+            throws IOException {
+        writerIndex += length;
+        return length;
+    }
+
+    @Override
+    public void writeZero(int length) {
+        writerIndex += length;
+
+    }
+
+    @Override
+    public int indexOf(int fromIndex, int toIndex, byte value) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public int indexOf(int fromIndex, int toIndex,
+            ChannelBufferIndexFinder indexFinder) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public int bytesBefore(byte value) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public int bytesBefore(ChannelBufferIndexFinder indexFinder) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public int bytesBefore(int length, byte value) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public int bytesBefore(int length, ChannelBufferIndexFinder indexFinder) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public int bytesBefore(int index, int length, byte value) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public int bytesBefore(int index, int length,
+            ChannelBufferIndexFinder indexFinder) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public ChannelBuffer copy() {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public ChannelBuffer copy(int index, int length) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public ChannelBuffer slice() {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public ChannelBuffer slice(int index, int length) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public ChannelBuffer duplicate() {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public ByteBuffer toByteBuffer() {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public ByteBuffer toByteBuffer(int index, int length) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public ByteBuffer[] toByteBuffers() {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public ByteBuffer[] toByteBuffers(int index, int length) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public boolean hasArray() {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public byte[] array() {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public int arrayOffset() {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public String toString(Charset charset) {
+        return "LengthCountingPseudoChannelBuffer(length="+writerIndex+")";
+    }
+
+    @Override
+    public String toString(int index, int length, Charset charset) {
+        return toString();
+    }
+
+    @Override
+    @Deprecated
+    public String toString(String charsetName) {
+        return toString();
+    }
+
+    @Override
+    @Deprecated
+    public String toString(String charsetName,
+            ChannelBufferIndexFinder terminatorFinder) {
+        return toString();
+    }
+
+    @Override
+    @Deprecated
+    public String toString(int index, int length, String charsetName) {
+        return toString();
+    }
+
+    @Override
+    @Deprecated
+    public
+    String toString(int index, int length, String charsetName,
+            ChannelBufferIndexFinder terminatorFinder) {
+        return toString();
+    }
+
+    @Override
+    public int compareTo(ChannelBuffer buffer) {
+        throw new UnsupportedOperationException();
+
+    }
+
+}
diff --git a/java_gen/pre-written/src/test/java/org/openflow/types/U64Test.java b/java_gen/pre-written/src/test/java/org/openflow/types/U64Test.java
new file mode 100644
index 0000000..16d3d3e
--- /dev/null
+++ b/java_gen/pre-written/src/test/java/org/openflow/types/U64Test.java
@@ -0,0 +1,26 @@
+package org.openflow.types;
+
+import static org.junit.Assert.assertEquals;
+
+import java.math.BigInteger;
+
+import org.junit.Test;
+
+public class U64Test {
+
+    @Test
+    public void testPositiveRaws() {
+        for(long positive: new long[] { 0, 1, 100, Long.MAX_VALUE }) {
+            assertEquals(positive, U64.of(positive).getValue());
+            assertEquals(BigInteger.valueOf(positive), U64.of(positive).getBigInteger());
+        }
+    }
+
+    @Test
+    public void testNegativeRaws() {
+        long minus_1 = 0xFFffFFffFFffFFffL;
+        assertEquals(minus_1, U64.of(minus_1).getValue());
+        assertEquals(new BigInteger("FFffFFffFFffFFff", 16),  U64.of(minus_1).getBigInteger());
+        assertEquals(new BigInteger("18446744073709551615"),  U64.of(minus_1).getBigInteger());
+    }
+}
diff --git a/java_gen/templates/_field_accessors.java b/java_gen/templates/_field_accessors.java
new file mode 100644
index 0000000..e8afe47
--- /dev/null
+++ b/java_gen/templates/_field_accessors.java
@@ -0,0 +1,33 @@
+//:: for prop in msg.interface.members:
+    @Override
+    public ${prop.java_type.public_type} get${prop.title_name}()${ "" if prop in msg.members else "throws UnsupportedOperationException"} {
+//:: if prop in msg.members:
+//::    version_prop = msg.get_member(prop.name)
+//::    if version_prop.is_fixed_value:
+        return ${version_prop.enum_value};
+//::    elif version_prop.is_length_value:
+        // FIXME: Hacky and inperformant way to determine a message length. Should be replaced with something better
+        ChannelBuffer c = new LengthCountingPseudoChannelBuffer();
+        WRITER.write(c, ${ "this" if not builder else "({0}) this.getMessage()".format(msg.name) });
+        return c.writerIndex();
+//::    else:
+        return ${version_prop.name};
+//::    #endif
+//:: else:
+        throw new UnsupportedOperationException("Property ${prop.name} not supported in version #{version}");
+//:: #endif
+    }
+
+//:: if generate_setters and prop.is_writeable:
+    @Override
+    public ${msg.interface.name}.Builder set${prop.title_name}(${prop.java_type.public_type} ${prop.name})${ "" if prop in msg.members else " throws UnsupportedOperationException"} {
+//:: if prop in msg.members:
+        this.${prop.name} = ${prop.name};
+        this.${prop.name}Set = true;
+        return this;
+//:: else:
+            throw new UnsupportedOperationException("Property ${prop.name} not supported in version #{version}");
+//:: #endif
+    }
+//:: #endif
+//:: #endfor
diff --git a/java_gen/templates/_imports.java b/java_gen/templates/_imports.java
new file mode 100644
index 0000000..7700546
--- /dev/null
+++ b/java_gen/templates/_imports.java
@@ -0,0 +1,12 @@
+import java.util.Collections;
+import java.util.List;
+import org.openflow.protocol.*;
+import org.openflow.protocol.action.*;
+import org.openflow.protocol.instruction.*;
+import org.openflow.protocol.match.*;
+import org.openflow.protocol.oxm.*;
+import org.openflow.types.*;
+import org.openflow.types.*;
+import org.openflow.util.*;
+import org.openflow.exceptions.*;
+import org.jboss.netty.buffer.ChannelBuffer;
diff --git a/java_gen/templates/of_type.java b/java_gen/templates/const.java
similarity index 74%
rename from java_gen/templates/of_type.java
rename to java_gen/templates/const.java
index 951a648..7870529 100644
--- a/java_gen/templates/of_type.java
+++ b/java_gen/templates/const.java
@@ -31,21 +31,22 @@
 
 //:: include('_autogen.java')
 
-package org.openflow.types;
+package ${package};
 
 import org.openflow.protocol.OFVersion;
 
-public enum OFType {
-//:: for i, msg in enumerate(all_messages):
-     ${msg.constant_name}(new byte[] { ${ ", ".join( [str(msg.wire_type(version)) for version in all_versions ]) } } )${ ", " if i < len(all_messages)-1 else ";" }
+public enum ${class_name} {
+//:: for i, entry in enumerate(enum.entries):
+//::     values = [ ("0x%x" % val) if val is not None else "-1" for val in entry.all_values(all_versions) ]
+     ${entry.name}(new int[] { ${ ", ".join( values) } } )${ ", " if i < len(enum.entries)-1 else ";" }
 //:: #endfor
 
-    byte[] wireTypes;
-    OFType(byte[] wireTypes) {
-        this.wireTypes = wireTypes;
+    private final int[] wireValues;
+    ${class_name}(int[] wireValues) {
+        this.wireValues = wireValues;
     }
 
-    public byte getWireType(OFVersion version) {
-        return this.wireTypes[version.getWireVersion()];
+    public int getWireValue(OFVersion version) {
+        return this.wireValues[version.getWireVersion()];
     }
 }
diff --git a/java_gen/templates/message_class.java b/java_gen/templates/message_class.java
deleted file mode 100644
index 2b4801c..0000000
--- a/java_gen/templates/message_class.java
+++ /dev/null
@@ -1,258 +0,0 @@
-//:: # Copyright 2013, Big Switch Networks, Inc.
-//:: #
-//:: # LoxiGen is licensed under the Eclipse Public License, version 1.0 (EPL), with
-//:: # the following special exception:
-//:: #
-//:: # LOXI Exception
-//:: #
-//:: # As a special exception to the terms of the EPL, you may distribute libraries
-//:: # generated by LoxiGen (LoxiGen Libraries) under the terms of your choice, provided
-//:: # that copyright and licensing notices generated by LoxiGen are not altered or removed
-//:: # from the LoxiGen Libraries and the notice provided below is (i) included in
-//:: # the LoxiGen Libraries, if distributed in source code form and (ii) included in any
-//:: # documentation for the LoxiGen Libraries, if distributed in binary form.
-//:: #
-//:: # Notice: "Copyright 2013, Big Switch Networks, Inc. This library was generated by the LoxiGen Compiler."
-//:: #
-//:: # You may not use this file except in compliance with the EPL or LOXI Exception. You may obtain
-//:: # a copy of the EPL at:
-//:: #
-//:: # http::: #www.eclipse.org/legal/epl-v10.html
-//:: #
-//:: # Unless required by applicable law or agreed to in writing, software
-//:: # distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
-//:: # WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
-//:: # EPL for the specific language governing permissions and limitations
-//:: # under the EPL.
-//::
-//:: import itertools
-//:: import of_g
-//:: include('_copyright.java')
-
-//:: include('_autogen.java')
-
-package org.openflow.protocol;
-import java.util.Collections;
-import java.util.List;
-import org.openflow.protocol.actions.OFAction;
-import org.openflow.protocol.instructions.OFInstruction;
-import org.openflow.protocol.match.*;
-import org.openflow.types.*;
-import org.openflow.types.*;
-import org.openflow.util.*;
-import org.openflow.exceptions.*;
-import org.jboss.netty.buffer.ChannelBuffer;
-
-class ${impl_class} implements ${msg.interface_name} {
-//:: if msg.is_fixed_length(version):
-    private static final int LENGTH = ${msg.min_length(version) };
-//:: else:
-    private static final int MINIMUM_LENGTH = ${msg.min_length(version) };
-//:: #endif
-
-//:: for prop in msg.properties_for_version(version):
-    private final static ${prop.java_type.public_type} ${prop.default_name} = ${prop.default_value};
-//:: #end
-    private boolean xidSet;
-    private final int xid;
-
-    // OF message fields
-//:: for prop in msg.properties_for_version(version):
-    private final ${prop.java_type.public_type} ${prop.name};
-//:: #endfor
-
-    // Constructor
-    ${impl_class}(${
-        ", ".join(["int xid" ] + [ "%s %s" %(prop.java_type.public_type, prop.name) for prop in msg.properties_for_version(version) ])}) {
-        this.xidSet = true;
-        this.xid = xid;
-//:: for prop in msg.properties_for_version(version):
-        this.${prop.name} = ${prop.name};
-//:: #endfor
-    }
-
-    ${impl_class}(${
-        ", ".join("%s %s" %(prop.java_type.public_type, prop.name) for prop in msg.properties_for_version(version)) }) {
-        this.xidSet = false;
-        this.xid = 0;
-//:: for prop in msg.properties_for_version(version):
-        this.${prop.name} = ${prop.name};
-//:: #endfor
-    }
-
-    @Override
-    public int getXid() {
-        return xid;
-    }
-
-    @Override
-    public boolean isXidSet() {
-        return xidSet;
-    }
-
-    @Override
-    public OFType getType() {
-        return OFType.${msg.constant_name};
-    }
-
-    @Override
-    public OFVersion getVersion() {
-        return OFVersion.${version.constant_version};
-    }
-
-    // Accessors for OF message fields
-//:: for prop in msg.all_properties():
-    @Override
-    public ${prop.java_type.public_type} get${prop.title_name}()${ "" if msg.property_in_version(prop, version) else "throws UnsupportedOperationException"} {
-//:: if msg.property_in_version(prop, version):
-        return ${prop.name};
-//:: else:
-        throw new UnsupportedOperationException("Property ${prop.name} not supported in version #{version}");
-//:: #endif
-    }
-//:: #endfor
-
-    public ${msg.interface_name}.Builder createBuilder() {
-        return new BuilderImplWithParent(this);
-    }
-
-    static class BuilderImplWithParent implements ${msg.interface_name}.Builder {
-        final ${impl_class} parentMessage;
-        private boolean xidSet;
-        private int xid;
-
-        // OF message fields
-//:: for prop in msg.properties_for_version(version):
-        private boolean ${prop.name}Set;
-        private ${prop.java_type.public_type} ${prop.name};
-//:: #endfor
-
-        BuilderImplWithParent(${impl_class} parentMessage) {
-            this.parentMessage = parentMessage;
-        }
-
-//:: for prop in msg.all_properties():
-        @Override
-        public ${prop.java_type.public_type} get${prop.title_name}()${ "" if msg.property_in_version(prop, version) else " throws UnsupportedOperationException"} {
-//:: if msg.property_in_version(prop, version):
-            return ${prop.name};
-//:: else:
-            throw new UnsupportedOperationException("Property ${prop.name} not supported in version #{version}");
-//:: #endif
-        }
-        @Override
-        public ${msg.interface_name}.Builder set${prop.title_name}(${prop.java_type.public_type} ${prop.name})${ "" if msg.property_in_version(prop, version) else " throws UnsupportedOperationException"} {
-//:: if msg.property_in_version(prop, version):
-            this.${prop.name} = ${prop.name};
-            this.${prop.name}Set = true;
-            return this;
-//:: else:
-        throw new UnsupportedOperationException("Property ${prop.name} not supported in version #{version}");
-//:: #endif
-        }
-//:: #endfor
-        @Override
-        public ${msg.interface_name} getMessage() {
-            if(this.xidSet) {
-                return new ${impl_class}(
-                    ${",\n                      ".join(
-                         [ "xid" ] +
-                         [ "this.{0}Set ? this.{0} : parentMessage.{0}".format(prop.name)
-                             for prop in msg.properties_for_version(version)])}
-                    );
-            } else {
-                return new ${impl_class}(
-                    ${",\n                      ".join(
-                         [ "this.{0}Set ? this.{0} : parentMessage.{0}".format(prop.name)
-                             for prop in msg.properties_for_version(version)])}
-                    );
-            }
-        }
-    }
-
-    static class BuilderImpl implements ${msg.interface_name}.Builder {
-        private boolean xidSet;
-        private int xid;
-
-        // OF message fields
-//:: for prop in msg.properties_for_version(version):
-        private boolean ${prop.name}Set;
-        private ${prop.java_type.public_type} ${prop.name};
-//:: #endfor
-
-//:: for prop in msg.all_properties():
-        @Override
-        public ${prop.java_type.public_type} get${prop.title_name}()${ "" if msg.property_in_version(prop, version) else " throws UnsupportedOperationException"} {
-//:: if msg.property_in_version(prop, version):
-            return ${prop.name};
-//:: else:
-            throw new UnsupportedOperationException("Property ${prop.name} not supported in version #{version}");
-//:: #endif
-        }
-        @Override
-        public ${msg.interface_name}.Builder set${prop.title_name}(${prop.java_type.public_type} ${prop.name})${ "" if msg.property_in_version(prop, version) else " throws UnsupportedOperationException"} {
-//:: if msg.property_in_version(prop, version):
-            this.${prop.name} = ${prop.name};
-            this.${prop.name}Set = true;
-            return this;
-//:: else:
-        throw new UnsupportedOperationException("Property ${prop.name} not supported in version #{version}");
-//:: #endif
-        }
-//:: #endfor
-        @Override
-        public ${msg.interface_name} getMessage() {
-            if(this.xidSet) {
-                return new ${impl_class}(
-                    ${",\n                      ".join(
-                         [ "xid" ] +
-                         [ "this.{0}Set ? this.{0} : {1}.{2}".format(prop.name, impl_class, prop.default_name)
-                             for prop in msg.properties_for_version(version)])}
-                    );
-            } else {
-                return new ${impl_class}(
-                    ${",\n                      ".join(
-                         [ "this.{0}Set ? this.{0} : {1}.{2}".format(prop.name, impl_class, prop.default_name)
-                             for prop in msg.properties_for_version(version)])}
-                    );
-            }
-        }
-    }
-
-    final static Reader READER = new Reader();
-    static class Reader implements OFMessageReader<${msg.interface_name}> {
-        @Override
-        public ${msg.interface_name} readFrom(ChannelBuffer bb) throws OFParseError {
-            byte version = bb.readByte();
-            if (version != (byte) ${version.int_version})
-                throw new OFParseError("Wrong version: Expected=${version.int_version}, got="+version);
-
-            byte type = bb.readByte();
-            if(type != ${msg.wire_type(version)})
-                throw new OFParseError("Wrong message type: Expected=${msg.constant_name}, got="+type);
-
-            int length = bb.readUnsignedShort();
-//:: if msg.is_fixed_length(version):
-            if(length != LENGTH)
-                throw new OFParseError("Wrong message length: Expected="+LENGTH +", got="+length);
-//:: else:
-            if(length < MINIMUM_LENGTH)
-                throw new OFParseError("Insufficient message length: minimum length="+MINIMUM_LENGTH +", got="+length);
-//:: #endif
-            int xid = bb.readInt();
-//:: for prop in msg.properties_for_version(version, skip_pads=False):
-//:: if prop.is_pad:
-            // pad: ${prop.length} bytes
-            bb.skipBytes(${prop.length});
-//:: else:
-            ${prop.java_type.public_type} ${prop.name} = ${prop.java_type.read_op(version)};
-//:: #endif
-//:: #endfor
-                return new ${impl_class}(
-                    ${",\n                      ".join(
-                         [ "xid" ] + [ prop.name for prop in msg.properties_for_version(version)])}
-                    );
-        }
-    }
-
-}
diff --git a/java_gen/templates/of_class.java b/java_gen/templates/of_class.java
new file mode 100644
index 0000000..772858a
--- /dev/null
+++ b/java_gen/templates/of_class.java
@@ -0,0 +1,209 @@
+//:: # Copyright 2013, Big Switch Networks, Inc.
+//:: #
+//:: # LoxiGen is licensed under the Eclipse Public License, version 1.0 (EPL), with
+//:: # the following special exception:
+//:: #
+//:: # LOXI Exception
+//:: #
+//:: # As a special exception to the terms of the EPL, you may distribute libraries
+//:: # generated by LoxiGen (LoxiGen Libraries) under the terms of your choice, provided
+//:: # that copyright and licensing notices generated by LoxiGen are not altered or removed
+//:: # from the LoxiGen Libraries and the notice provided below is (i) included in
+//:: # the LoxiGen Libraries, if distributed in source code form and (ii) included in any
+//:: # documentation for the LoxiGen Libraries, if distributed in binary form.
+//:: #
+//:: # Notice: "Copyright 2013, Big Switch Networks, Inc. This library was generated by the LoxiGen Compiler."
+//:: #
+//:: # You may not use this file except in compliance with the EPL or LOXI Exception. You may obtain
+//:: # a copy of the EPL at:
+//:: #
+//:: # http::: #www.eclipse.org/legal/epl-v10.html
+//:: #
+//:: # Unless required by applicable law or agreed to in writing, software
+//:: # distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+//:: # WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+//:: # EPL for the specific language governing permissions and limitations
+//:: # under the EPL.
+//::
+//:: from loxi_ir import *
+//:: import itertools
+//:: import of_g
+//:: include('_copyright.java')
+
+//:: include('_autogen.java')
+
+package ${msg.package};
+
+//:: include("_imports.java", msg=msg)
+
+class ${impl_class} implements ${msg.interface.name} {
+    // version: ${version}
+    private final static byte WIRE_VERSION = ${version.int_version};
+//:: if msg.is_fixed_length:
+    private final static int LENGTH = ${msg.length};
+//:: else:
+    private final static int MINIMUM_LENGTH = ${msg.min_length};
+//:: #endif
+
+//:: for prop in msg.data_members:
+    private final static ${prop.java_type.public_type} ${prop.default_name} = ${prop.default_value};
+//:: #end
+
+    // OF message fields
+//:: for prop in msg.data_members:
+    private final ${prop.java_type.public_type} ${prop.name};
+//:: #endfor
+
+    ${impl_class}(${
+        ", ".join("%s %s" %(prop.java_type.public_type, prop.name) for prop in msg.data_members) }) {
+//:: for prop in msg.data_members:
+        this.${prop.name} = ${prop.name};
+//:: #endfor
+    }
+
+    // Accessors for OF message fields
+//:: include("_field_accessors.java", msg=msg, generate_setters=False, builder=False)
+
+
+    public ${msg.name}.Builder createBuilder() {
+        return new BuilderImplWithParent(this);
+    }
+
+    static class BuilderImplWithParent implements ${msg.interface.name}.Builder {
+        final ${impl_class} parentMessage;
+
+        // OF message fields
+//:: for prop in msg.data_members:
+        private boolean ${prop.name}Set;
+        private ${prop.java_type.public_type} ${prop.name};
+//:: #endfor
+
+        BuilderImplWithParent(${impl_class} parentMessage) {
+            this.parentMessage = parentMessage;
+        }
+
+//:: include("_field_accessors.java", msg=msg, generate_setters=True, builder=True)
+
+        @Override
+        public ${msg.interface.name} getMessage() {
+                return new ${impl_class}(
+                    ${",\n                      ".join(
+                         [ "this.{0}Set ? this.{0} : parentMessage.{0}".format(prop.name)
+                             for prop in msg.data_members])}
+                    );
+        }
+    }
+
+    static class BuilderImpl implements ${msg.interface.name}.Builder {
+        // OF message fields
+//:: for prop in msg.data_members:
+        private boolean ${prop.name}Set;
+        private ${prop.java_type.public_type} ${prop.name};
+//:: #endfor
+
+//:: include("_field_accessors.java", msg=msg, generate_setters=True, builder=True)
+//
+        @Override
+        public ${msg.interface.name} getMessage() {
+            return new ${impl_class}(
+                ${",\n                      ".join(
+                     [ "this.{0}Set ? this.{0} : {1}.{2}".format(prop.name, impl_class, prop.default_name)
+                         for prop in msg.data_members])}
+                );
+        }
+    }
+
+    final static Reader READER = new Reader();
+    static class Reader implements OFMessageReader<${msg.interface.name}> {
+        @Override
+        public ${msg.interface.name} readFrom(ChannelBuffer bb) throws OFParseError {
+//:: fields_with_length_member = {}
+//:: for prop in msg.members:
+//:: if prop.is_data:
+            ${prop.java_type.public_type} ${prop.name} = ${prop.java_type.read_op(version,
+                    length=fields_with_length_member[prop.c_name] if prop.c_name in fields_with_length_member else None)};
+//:: elif prop.is_pad:
+            // pad: ${prop.length} bytes
+            bb.skipBytes(${prop.length});
+//:: elif prop.is_fixed_value:
+            // fixed value property ${prop.name} == ${prop.value}
+            ${prop.java_type.priv_type} ${prop.name} = ${prop.java_type.read_op(version)};
+            if(${prop.name} != ${prop.value})
+                throw new OFParseError("Wrong ${prop.name}: Expected=${prop.enum_value}(${prop.value}), got="+${prop.name});
+//:: elif prop.is_length_value:
+            ${prop.java_type.public_type} ${prop.name} = ${prop.java_type.read_op(version)};
+            if(${prop.name} < MINIMUM_LENGTH)
+                throw new OFParseError("Wrong ${prop.name}: Expected to be >= " + MINIMUM_LENGTH + ", was: " + ${prop.name});
+//:: elif prop.is_field_length_value:
+//::        fields_with_length_member[prop.member.field_name] = prop.name
+            int ${prop.name} = ${prop.java_type.read_op(version)};
+//:: else:
+    // fixme: todo ${prop.name}
+//:: #endif
+//:: #endfor
+            return new ${impl_class}(
+                    ${",\n                      ".join(
+                         [ prop.name for prop in msg.data_members])}
+                    );
+        }
+    }
+
+    public int writeTo(ChannelBuffer bb) {
+        return WRITER.write(bb, this);
+    }
+
+    final static Writer WRITER = new Writer();
+    static class Writer implements OFMessageWriter<${impl_class}> {
+        @Override
+        public int write(ChannelBuffer bb, ${impl_class} message) {
+//:: if not msg.is_fixed_length:
+            int startIndex = bb.writerIndex();
+//:: #end
+
+//:: fields_with_length_member = {}
+//:: for prop in msg.members:
+//:: if prop.c_name in fields_with_length_member:
+            int ${prop.name}StartIndex = bb.writerIndex();
+//:: #endif
+//:: if prop.is_data:
+            ${prop.java_type.write_op(version, "message." + prop.name)};
+//:: elif prop.is_pad:
+            // pad: ${prop.length} bytes
+            bb.writeZero(${prop.length});
+//:: elif prop.is_fixed_value:
+            // fixed value property ${prop.name} = ${prop.value}
+            ${prop.java_type.write_op(version, prop.value)};
+//:: elif prop.is_length_value:
+            // ${prop.name} is length of variable message, will be updated at the end
+            ${prop.java_type.write_op(version, 0)};
+//:: elif prop.is_field_length_value:
+//::        fields_with_length_member[prop.member.field_name] = prop.name
+            // ${prop.name} is length indicator for ${prop.member.field_name}, will be
+            // udpated when ${prop.member.field_name} has been written
+            int ${prop.name}Index = bb.writerIndex();
+            ${prop.java_type.write_op(version, 0)};
+//:: else:
+            // FIXME: todo write ${prop.name}
+//:: #endif
+//:: if prop.c_name in fields_with_length_member:
+//::     length_member_name = fields_with_length_member[prop.c_name]
+            // update field length member ${length_member_name}
+            int ${prop.name}Length = bb.writerIndex() - ${prop.name}StartIndex;
+            bb.setShort(${length_member_name}Index, ${prop.name}Length);
+//:: #endif
+//:: #endfor
+
+//:: if msg.is_fixed_length:
+            return LENGTH;
+//:: else:
+            // update length field
+            int length = bb.writerIndex() - startIndex;
+            bb.setShort(startIndex + 2, length);
+            return length;
+//:: #end
+
+        }
+    }
+
+
+}
diff --git a/java_gen/templates/message_interface.java b/java_gen/templates/of_interface.java
similarity index 71%
rename from java_gen/templates/message_interface.java
rename to java_gen/templates/of_interface.java
index 904be95..af6493e 100644
--- a/java_gen/templates/message_interface.java
+++ b/java_gen/templates/of_interface.java
@@ -31,32 +31,25 @@
 
 //:: include('_autogen.java')
 
-package org.openflow.protocol;
-import java.util.List;
-import org.openflow.protocol.match.*;
-import org.openflow.protocol.actions.OFAction;
-import org.openflow.protocol.instructions.OFInstruction;
-import org.openflow.types.*;
-import org.openflow.util.*;
-import org.openflow.exceptions.OFUnsupported;
+package ${msg.package};
 
-public interface ${msg.interface_name} extends OFMessage {
-    int getXid();
-    boolean isXidSet();
-    OFType getType();
-    OFVersion getVersion();
+//:: include("_imports.java", msg=msg)
 
-//:: for prop in msg.all_properties():
-    ${prop.java_type.public_type} get${prop.title_name}()${ "" if prop.is_universal else "throws UnsupportedOperationException"};
+public interface ${msg.name} ${"extends %s" % msg.parent_interface if msg.parent_interface else ""} {
+//:: for prop in msg.members:
+    ${prop.java_type.public_type} get${prop.title_name}()${ "" if prop.is_universal else " throws UnsupportedOperationException"};
 //:: #endfor
 
-    Builder createBuilder();
+    int writeTo(ChannelBuffer channelBuffer);
 
-    public interface Builder {
-        ${msg.interface_name} getMessage();
-//:: for prop in msg.all_properties():
-        ${prop.java_type.public_type} get${prop.title_name}()${ "" if prop.is_universal else "throws UnsupportedOperationException"};
+    Builder createBuilder();
+    public interface Builder ${"extends %s.Builder" % msg.parent_interface if msg.parent_interface else ""} {
+        ${msg.name} getMessage();
+//:: for prop in msg.members:
+        ${prop.java_type.public_type} get${prop.title_name}()${ "" if prop.is_universal else " throws UnsupportedOperationException"};
+//:: if prop.is_writeable:
         Builder set${prop.title_name}(${prop.java_type.public_type} ${prop.name})${ "" if prop.is_universal else " throws UnsupportedOperationException"};
+//:: #endif
 //:: #endfor
 
     }
diff --git a/lang_java.py b/lang_java.py
index db23c82..be94e82 100644
--- a/lang_java.py
+++ b/lang_java.py
@@ -42,35 +42,9 @@
 
 """
 
-import java_gen.java_code_gen as java_code_gen
+import java_gen.codegen as java_codegen
 
 
 targets = {
-    'base_java': java_code_gen.gen_all_java
+    'openflowj/README': java_codegen.gen_all_java
 }
-
-##
-# The list of files to produce.  These are the keywords used to index
-# the arrays below giving the external file names, the subdirectory locations
-# and the generating functions.
-
-target_files =  ["base_java" ]
-# Internal file name references to actual file names
-file_to_name_map = dict(
-    # LOCI source
-    base_java="README.openflowj", # not really used by java generator
-)
-
-##
-# The map from the internal file identifier to the function name
-# that generates the content of the file
-
-file_gen_map = dict(
-    base_java=java_code_gen.gen_all_java,
-)
-
-
-# Map from file references to target sub-directories
-file_to_subdir_map = dict(
-    base_java="openflowj/",
-)
diff --git a/loxi_front_end/match.py b/loxi_front_end/match.py
index 42c0a9e..20d5030 100644
--- a/loxi_front_end/match.py
+++ b/loxi_front_end/match.py
@@ -147,7 +147,7 @@
         ),
     ipv4_src = dict(
         name="ipv4_src",
-        m_type="uint32_t",
+        m_type="of_ipv4_t",
         v1_wc_shift=8,
         print_type="PRIx32",
         conditions="is_ipv4(match)",
@@ -156,7 +156,7 @@
         ),
     ipv4_dst = dict(
         name="ipv4_dst",
-        m_type="uint32_t",
+        m_type="of_ipv4_t",
         v1_wc_shift=14,
         print_type="PRIx32",
         conditions="is_ipv4(match)",
diff --git a/loxigen.py b/loxigen.py
index 1d1f245..36d6872 100755
--- a/loxigen.py
+++ b/loxigen.py
@@ -442,7 +442,12 @@
                                                    name=m_name))
                         pad_count += 1
                     else:
-                        legacy_members.append(dict(m_type=m.oftype, name=m.name))
+                        # HACK the C backend does not yet support of_oxm_t
+                        if m.oftype == 'of_oxm_t':
+                            m_type = 'of_octets_t'
+                        else:
+                            m_type = m.oftype
+                        legacy_members.append(dict(m_type=m_type, name=m.name))
                 versions[version_name]['classes'][ofclass.name] = legacy_members
 
             for enum in ofinput.enums:
diff --git a/of_g.py b/of_g.py
index 2e8b5ba..651ee64 100644
--- a/of_g.py
+++ b/of_g.py
@@ -280,6 +280,7 @@
 #    of_counter_t = dict(bytes=8, to_w="u64_hton", from_w="u64_ntoh", use_as_rv=1,
 #                    short_name="counter"),
     of_mac_addr_t = dict(bytes=6, short_name="mac"),
+    of_ipv4_t = dict(bytes=4, short_name="ipv4"),
     of_ipv6_t = dict(bytes=16, short_name="ipv6"),
     of_port_name_t = dict(bytes=ofp_constants["OF_MAX_PORT_NAME_LEN"],
                           short_name="port_name"),
@@ -308,7 +309,7 @@
                    "of_port_no_t", "of_fm_cmd_t", "of_wc_bmap_t",
                    "of_match_bmap_t", "of_port_name_t", "of_table_name_t",
                    "of_desc_str_t", "of_serial_num_t", "of_mac_addr_t",
-                   "of_ipv6_t"]
+                   "of_ipv6_t", "of_ipv4_t"]
 
 base_object_members = """\
     /* The control block for the underlying data buffer */
diff --git a/openflow_input/bsn_get_interfaces b/openflow_input/bsn_get_interfaces
index ba1508c..01902bc 100644
--- a/openflow_input/bsn_get_interfaces
+++ b/openflow_input/bsn_get_interfaces
@@ -40,8 +40,8 @@
     of_mac_addr_t hw_addr;
     pad(2);
     of_port_name_t name;
-    uint32_t ipv4_addr;
-    uint32_t ipv4_netmask;
+    of_ipv4_t ipv4_addr;
+    of_ipv4_t ipv4_netmask;
 };
 
 struct of_bsn_get_interfaces_reply {
diff --git a/openflow_input/oxm-1.2 b/openflow_input/oxm-1.2
index b18c6fb..01af6c6 100644
--- a/openflow_input/oxm-1.2
+++ b/openflow_input/oxm-1.2
@@ -227,24 +227,24 @@
 
 struct of_oxm_ipv4_dst {
     uint32_t type_len == 0x80001804;
-    uint32_t value;
+    of_ipv4_t value;
 };
 
 struct of_oxm_ipv4_dst_masked {
     uint32_t type_len == 0x80001908;
-    uint32_t value;
-    uint32_t value_mask;
+    of_ipv4_t value;
+    of_ipv4_t value_mask;
 };
 
 struct of_oxm_ipv4_src {
     uint32_t type_len == 0x80001604;
-    uint32_t value;
+    of_ipv4_t value;
 };
 
 struct of_oxm_ipv4_src_masked {
     uint32_t type_len == 0x80001708;
-    uint32_t value;
-    uint32_t value_mask;
+    of_ipv4_t value;
+    of_ipv4_t value_mask;
 };
 
 struct of_oxm_ipv6_dst {
diff --git a/openflow_input/standard-1.0 b/openflow_input/standard-1.0
index 5d4405c..e9cb6f0 100644
--- a/openflow_input/standard-1.0
+++ b/openflow_input/standard-1.0
@@ -563,8 +563,8 @@
     uint8_t ip_dscp;
     uint8_t ip_proto;
     pad(2);
-    uint32_t ipv4_src;
-    uint32_t ipv4_dst;
+    of_ipv4_t ipv4_src;
+    of_ipv4_t ipv4_dst;
     uint16_t tcp_src;
     uint16_t tcp_dst;
 };
diff --git a/openflow_input/standard-1.1 b/openflow_input/standard-1.1
index a477d55..553e665 100644
--- a/openflow_input/standard-1.1
+++ b/openflow_input/standard-1.1
@@ -779,10 +779,10 @@
     uint16_t eth_type;
     uint8_t ip_dscp;
     uint8_t ip_proto;
-    uint32_t ipv4_src;
-    uint32_t ipv4_src_mask;
-    uint32_t ipv4_dst;
-    uint32_t ipv4_dst_mask;
+    of_ipv4_t ipv4_src;
+    of_ipv4_t ipv4_src_mask;
+    of_ipv4_t ipv4_dst;
+    of_ipv4_t ipv4_dst_mask;
     uint16_t tcp_src;
     uint16_t tcp_dst;
     uint32_t mpls_label;
diff --git a/openflow_input/standard-1.2 b/openflow_input/standard-1.2
index 4650e06..8b4fa3f 100644
--- a/openflow_input/standard-1.2
+++ b/openflow_input/standard-1.2
@@ -692,7 +692,7 @@
 struct of_action_set_field {
     uint16_t type == 25;
     uint16_t len;
-    of_octets_t field;
+    of_oxm_t field;
 };
 
 struct of_action_experimenter {
diff --git a/openflow_input/standard-1.3 b/openflow_input/standard-1.3
index ccef4db..0d5cec3 100644
--- a/openflow_input/standard-1.3
+++ b/openflow_input/standard-1.3
@@ -824,7 +824,7 @@
 struct of_action_set_field {
     uint16_t type == 25;
     uint16_t len;
-    of_octets_t field;
+    of_oxm_t field;
 };
 
 struct of_action_experimenter {
diff --git a/py_gen/codegen.py b/py_gen/codegen.py
index 4e93c4c..6570938 100644
--- a/py_gen/codegen.py
+++ b/py_gen/codegen.py
@@ -35,7 +35,8 @@
 from loxi_ir import *
 
 PyOFClass = namedtuple('PyOFClass', ['name', 'pyname', 'members', 'type_members',
-                                     'min_length', 'is_fixed_length'])
+                                     'min_length', 'is_fixed_length',
+                                     'has_internal_alignment', 'has_external_alignment'])
 
 # Return the name for the generated Python class
 def generate_pyname(cls):
@@ -92,7 +93,9 @@
                       members=members,
                       type_members=type_members,
                       min_length=of_g.base_length[(cls, version)],
-                      is_fixed_length=(cls, version) in of_g.is_fixed_length))
+                      is_fixed_length=(cls, version) in of_g.is_fixed_length,
+                      has_internal_alignment=cls == 'of_action_set_field',
+                      has_external_alignment=cls == 'of_match_v3'))
     return ofclasses
 
 def generate_init(out, name, version):
diff --git a/py_gen/oftype.py b/py_gen/oftype.py
index cf87ded..2399266 100644
--- a/py_gen/oftype.py
+++ b/py_gen/oftype.py
@@ -78,6 +78,11 @@
         pack='util.pack_match_bmap(%s)',
         unpack='util.unpack_match_bmap(%s)'),
 
+    'of_ipv4_t': OFTypeData(
+        init='0',
+        pack='struct.pack("!L", %s)',
+        unpack='%s.read("!L")[0]'),
+
     'of_ipv6_t': OFTypeData(
         init="'\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00'",
         pack='struct.pack("!16s", %s)',
@@ -99,6 +104,11 @@
         pack='util.pack_list(%s)',
         unpack='oxm.unpack_list(%s.slice(_length-4))'),
 
+    'of_oxm_t': OFTypeData(
+        init='None',
+        pack='%s.pack()',
+        unpack='oxm.unpack(%s)'),
+
     # TODO implement unpack
     'list(of_table_features_t)': OFTypeData(
         init='[]',
diff --git a/py_gen/templates/_pack.py b/py_gen/templates/_pack.py
index 4714e97..9956cf6 100644
--- a/py_gen/templates/_pack.py
+++ b/py_gen/templates/_pack.py
@@ -56,8 +56,12 @@
 :: #endfor
 :: if length_member_index != None:
         length = sum([len(x) for x in packed])
+:: if ofclass.has_internal_alignment:
+        packed.append(loxi.generic_util.pad_to(8, length))
+        length += len(packed[-1])
+:: #endif
         packed[${length_member_index}] = ${gen_pack_expr(length_member.oftype, 'length')}
 :: #endif
-:: if ofclass.name == 'of_match_v3':
-        packed.append('\x00' * ((length + 7)/8*8 - length))
+:: if ofclass.has_external_alignment:
+        packed.append(loxi.generic_util.pad_to(8, length))
 :: #endif
diff --git a/py_gen/templates/_pretty_print.py b/py_gen/templates/_pretty_print.py
index 7be7a14..ed9d5cc 100644
--- a/py_gen/templates/_pretty_print.py
+++ b/py_gen/templates/_pretty_print.py
@@ -46,7 +46,7 @@
                     q.text('None')
 :: elif m.oftype == 'of_mac_addr_t':
                 q.text(util.pretty_mac(self.${m.name}))
-:: elif m.oftype == 'uint32_t' and m.name.startswith("ipv4"):
+:: elif m.oftype == 'of_ipv4_t':
                 q.text(util.pretty_ipv4(self.${m.name}))
 :: elif m.oftype == 'of_wc_bmap_t' and version in [1,2]:
                 q.text(util.pretty_wildcards(self.${m.name}))
diff --git a/py_gen/templates/_unpack.py b/py_gen/templates/_unpack.py
index 133e831..09a0e08 100644
--- a/py_gen/templates/_unpack.py
+++ b/py_gen/templates/_unpack.py
@@ -53,6 +53,6 @@
         obj.${m.name} = ${gen_unpack_expr(m.oftype, reader_expr)}
 ::     #endif
 :: #endfor
-:: if ofclass.name == 'of_match_v3':
-        reader.skip((_length + 7)/8*8 - _length)
+:: if ofclass.has_external_alignment or ofclass.has_internal_alignment:
+        reader.skip_align()
 :: #endif
diff --git a/py_gen/templates/action.py b/py_gen/templates/action.py
index dccb46e..fba5294 100644
--- a/py_gen/templates/action.py
+++ b/py_gen/templates/action.py
@@ -37,6 +37,9 @@
 import util
 import loxi.generic_util
 import loxi
+:: if version >= 3:
+import oxm # for unpack
+:: #endif
 
 def unpack_list(reader):
     def deserializer(reader, typ):
diff --git a/py_gen/templates/generic_util.py b/py_gen/templates/generic_util.py
index 53091ed..28d3b5f 100644
--- a/py_gen/templates/generic_util.py
+++ b/py_gen/templates/generic_util.py
@@ -63,6 +63,13 @@
         return deserializer(reader.slice(length), typ)
     return unpack_list(reader, wrapper)
 
+def pad_to(alignment, length):
+    """
+    Return a string of zero bytes that will pad a string of length 'length' to
+    a multiple of 'alignment'.
+    """
+    return "\x00" * ((length + alignment - 1)/alignment*alignment - length)
+
 class OFReader(object):
     """
     Cursor over a read-only buffer
@@ -102,6 +109,12 @@
             raise loxi.ProtocolError("Buffer too short")
         self.offset += length
 
+    def skip_align(self):
+        new_offset = (self.offset + 7) / 8 * 8
+        if new_offset > len(self.buf):
+            raise loxi.ProtocolError("Buffer too short")
+        self.offset = new_offset
+
     def is_empty(self):
         return self.offset == len(self.buf)
 
diff --git a/py_gen/templates/oxm.py b/py_gen/templates/oxm.py
index d95dd8e..792c277 100644
--- a/py_gen/templates/oxm.py
+++ b/py_gen/templates/oxm.py
@@ -38,15 +38,16 @@
 import loxi.generic_util
 import loxi
 
+def unpack(reader):
+    type_len, = reader.peek('!L')
+    if type_len in parsers:
+        return parsers[type_len](reader)
+    else:
+        raise loxi.ProtocolError("unknown OXM cls=%#x type=%#x masked=%d len=%d (%#x)" % \
+            ((type_len >> 16) & 0xffff, (type_len >> 9) & 0x7f, (type_len >> 8) & 1, type_len & 0xff, type_len))
+
 def unpack_list(reader):
-    def deserializer(reader):
-        type_len, = reader.peek('!L')
-        if type_len in parsers:
-            return parsers[type_len](reader)
-        else:
-            raise loxi.ProtocolError("unknown OXM cls=%#x type=%#x masked=%d len=%d (%#x)" % \
-                ((type_len >> 16) & 0xffff, (type_len >> 9) & 0x7f, (type_len >> 8) & 1, type_len & 0xff, type_len))
-    return loxi.generic_util.unpack_list(reader, deserializer)
+    return loxi.generic_util.unpack_list(reader, unpack)
 
 class OXM(object):
     type_len = None # override in subclass
diff --git a/py_gen/tests/of12.py b/py_gen/tests/of12.py
index c6c94ab..98d999b 100644
--- a/py_gen/tests/of12.py
+++ b/py_gen/tests/of12.py
@@ -78,7 +78,9 @@
         self.klasses.sort(key=lambda x: str(x))
 
     def test_serialization(self):
-        expected_failures = []
+        expected_failures = [
+            ofp.action.set_field, # field defaults to None
+        ]
         for klass in self.klasses:
             def fn():
                 obj = klass()
diff --git a/py_gen/tests/of13.py b/py_gen/tests/of13.py
index 349881f..8c18f41 100644
--- a/py_gen/tests/of13.py
+++ b/py_gen/tests/of13.py
@@ -93,6 +93,7 @@
 
     def test_serialization(self):
         expected_failures = [
+            ofp.action.set_field, # field defaults to None
             ofp.common.table_feature_prop_apply_actions,
             ofp.common.table_feature_prop_apply_actions_miss,
             ofp.common.table_feature_prop_write_actions,
diff --git a/test_data/of13/action_output.data b/test_data/of13/action_output.data
new file mode 100644
index 0000000..7cd52ce
--- /dev/null
+++ b/test_data/of13/action_output.data
@@ -0,0 +1,8 @@
+-- binary
+00 00 # type
+00 10 # length
+00 00 00 32 # port
+ff ff # max_len
+00 00 00 00 00 00 # pad
+-- python
+ofp.action.output(port=50, max_len=65535)
diff --git a/test_data/of13/action_set_field_eth_dst.data b/test_data/of13/action_set_field_eth_dst.data
new file mode 100644
index 0000000..1e4a971
--- /dev/null
+++ b/test_data/of13/action_set_field_eth_dst.data
@@ -0,0 +1,8 @@
+-- binary
+00 19 # type
+00 10 # length
+80 00 06 06 # OXM header
+00 01 02 03 04 05 # OXM value
+00 00 # pad
+-- python
+ofp.action.set_field(field=ofp.oxm.eth_dst([0, 1, 2, 3, 4, 5]))
diff --git a/test_data/of13/action_set_field_ipv6_src.data b/test_data/of13/action_set_field_ipv6_src.data
new file mode 100644
index 0000000..f440dee
--- /dev/null
+++ b/test_data/of13/action_set_field_ipv6_src.data
@@ -0,0 +1,7 @@
+-- binary
+00 19 # type
+00 18 # length
+80 00 34 10 # OXM header
+00 01 02 03 04 05 06 07 08 09 0a 0b 0c 0d 0e 0f # OXM value
+-- python
+ofp.action.set_field(field=ofp.oxm.ipv6_src("\x00\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0a\x0b\x0c\x0d\x0e\x0f"))
diff --git a/test_data/of13/action_set_field_tcp_src.data b/test_data/of13/action_set_field_tcp_src.data
new file mode 100644
index 0000000..a69c7c0
--- /dev/null
+++ b/test_data/of13/action_set_field_tcp_src.data
@@ -0,0 +1,8 @@
+-- binary
+00 19 # type
+00 10 # length
+80 00 1a 02 # OXM header
+00 32 # OXM value
+00 00 00 00 00 00 # pad
+-- python
+ofp.action.set_field(field=ofp.oxm.tcp_src(50))