/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.onlab.netty;

import java.io.IOException;

/**
 * A unit of communication.
 * Has a payload. Also supports a feature to respond back to the sender.
 */
public interface Message {

    /**
     * Returns the payload of this message.
     * @return message payload.
     */
    public byte[] payload();

    /**
     * Sends a reply back to the sender of this message.
     * @param data payload of the response.
     * @throws IOException if there is a communication error.
     */
    public void respond(byte[] data) throws IOException;
}