--- /dev/null
+/**
+* Copyright 2011, Big Switch Networks, Inc.
+* Originally created by David Erickson & Rob Sherwood, Stanford University
+*
+* Licensed under the Apache License, Version 2.0 (the "License"); you may
+* not use this file except in compliance with the License. You may obtain
+* a copy of the License at
+*
+* http://www.apache.org/licenses/LICENSE-2.0
+*
+* 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
+* License for the specific language governing permissions and limitations
+* under the License.
+**/
+
+package org.openflow.vendor.nicira;
+
+import org.jboss.netty.buffer.ChannelBuffer;
+import org.openflow.protocol.vendor.OFVendorData;
+
+/**
+ * Base class for vendor data corresponding to a Nicira vendor extension.
+ * Nicira vendor data always starts with a 4-byte integer data type value.
+ *
+ * @author Rob Vaterlaus (rob.vaterlaus@bigswitch.com)
+ */
+public class OFNiciraVendorData implements OFVendorData {
+
+ public static final int NX_VENDOR_ID = 0x00002320;
+ /**
+ * The value of the integer data type at the beginning of the vendor data
+ */
+ protected int dataType;
+
+ /**
+ * Construct empty (i.e. unspecified data type) Nicira vendor data.
+ */
+ public OFNiciraVendorData() {
+ }
+
+ /**
+ * Contruct Nicira vendor data with the specified data type
+ * @param dataType the data type value at the beginning of the vendor data.
+ */
+ public OFNiciraVendorData(int dataType) {
+ this.dataType = dataType;
+ }
+
+ /**
+ * Get the data type value at the beginning of the vendor data
+ * @return the integer data type value
+ */
+ public int getDataType() {
+ return dataType;
+ }
+
+ /**
+ * Set the data type value
+ * @param dataType the integer data type value at the beginning of the
+ * vendor data.
+ */
+ public void setDataType(int dataType) {
+ this.dataType = dataType;
+ }
+
+ /**
+ * Get the length of the vendor data. This implementation will normally
+ * be the superclass for another class that will override this to return
+ * the overall vendor data length. This implementation just returns the
+ * length of the part that includes the 4-byte integer data type value
+ * at the beginning of the vendor data.
+ */
+ @Override
+ public int getLength() {
+ return 4;
+ }
+
+ /**
+ * Read the vendor data from the ChannelBuffer
+ * @param data the channel buffer from which we're deserializing
+ * @param length the length to the end of the enclosing message
+ */
+ @Override
+ public void readFrom(ChannelBuffer data, int length) {
+ dataType = data.readInt();
+ }
+
+ /**
+ * Write the vendor data to the ChannelBuffer
+ * @param data the channel buffer to which we're serializing
+ */
+ @Override
+ public void writeTo(ChannelBuffer data) {
+ data.writeInt(dataType);
+ }
+}