utils/netty/src/main/java/org/onlab/netty/MessagingService.java

/*
 * 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;

import com.google.common.util.concurrent.ListenableFuture;

/**
 * Interface for low level messaging primitives.
 */
public interface MessagingService {
    /**
     * Sends a message asynchronously to the specified communication end point.
     * The message is specified using the type and payload.
     * @param ep end point to send the message to.
     * @param type type of message.
     * @param payload message payload bytes.
     * @throws IOException
     */
    public void sendAsync(Endpoint ep, String type, byte[] payload) throws IOException;

    /**
     * Sends a message synchronously and waits for a response.
     * @param ep end point to send the message to.
     * @param type type of message.
     * @param payload message payload.
     * @return a response future
     * @throws IOException
     */
    public ListenableFuture<byte[]> sendAndReceive(Endpoint ep, String type, byte[] payload) throws IOException;

    /**
     * Registers a new message handler for message type.
     * @param type message type.
     * @param handler message handler
     */
    public void registerHandler(String type, MessageHandler handler);

    /**
     * Unregister current handler, if one exists for message type.
     * @param type message type
     */
    public void unregisterHandler(String type);
}