content: /*
   * 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.apache.celeborn.common.network.server;
  
  import org.apache.celeborn.common.network.protocol.Message;
  
  /**
   * Handles either request or response messages coming off of Netty. A MessageHandler instance is
   * associated with a single Netty Channel (though it may have multiple clients on the same Channel.)
   */
  public abstract class MessageHandler<T extends Message> {
    /** Handles the receipt of a single message. */
    public abstract void handle(T message) throws Exception;
  
    /** Invoked when the channel this MessageHandler is on is active. */
    public abstract void channelActive();
  
    /** Invoked when an exception was caught on the Channel. */
    public abstract void exceptionCaught(Throwable cause);
  
    /** Invoked when the channel this MessageHandler is on is inactive. */
    public abstract void channelInactive();
  }
  