ServiceClientHandshakeHandler.java

/*
 * Copyright (C) 2011 Google Inc.
 *
 * 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.ros.internal.node.service;

import org.apache.commons.logging.Log;
import org.jboss.netty.channel.ChannelHandlerContext;
import org.jboss.netty.channel.ChannelPipeline;
import org.jboss.netty.channel.MessageEvent;
import org.ros.internal.transport.BaseClientHandshakeHandler;
import org.ros.internal.transport.ConnectionHeader;
import org.ros.internal.transport.tcp.TcpRosClientPipelineFactory;
import org.ros.log.RosLogFactory;
import org.ros.message.MessageDeserializer;
import org.ros.node.service.ServiceResponseListener;
import org.ros.node.service.ServiceServer;

import java.util.Queue;
import java.util.concurrent.ExecutorService;

/**
 * Performs a handshake with the connected {@link ServiceServer}.
 *
 * @author damonkohler@google.com (Damon Kohler)
 *
 * @param <T>
 *          the connected {@link ServiceServer} responds to requests of this
 *          type
 * @param <S>
 *          the connected {@link ServiceServer} returns responses of this type
 */
class ServiceClientHandshakeHandler<T, S> extends BaseClientHandshakeHandler {

  private static final Log log = RosLogFactory.getLog(ServiceClientHandshakeHandler.class);

  private final Queue<ServiceResponseListener<S>> responseListeners;
  private final MessageDeserializer<S> deserializer;
  private final ExecutorService executorService;

  public ServiceClientHandshakeHandler(ConnectionHeader outgoingConnectionHeader,
      Queue<ServiceResponseListener<S>> responseListeners, MessageDeserializer<S> deserializer,
      ExecutorService executorService) {
    super(new ServiceClientHandshake(outgoingConnectionHeader), executorService);
    this.responseListeners = responseListeners;
    this.deserializer = deserializer;
    this.executorService = executorService;
  }

  @Override
  protected void onSuccess(ConnectionHeader incommingConnectionHeader, ChannelHandlerContext ctx,
      MessageEvent e) {
    ChannelPipeline pipeline = e.getChannel().getPipeline();
    pipeline.remove(TcpRosClientPipelineFactory.LENGTH_FIELD_BASED_FRAME_DECODER);
    pipeline.remove(ServiceClientHandshakeHandler.this);
    pipeline.addLast("ResponseDecoder", new ServiceResponseDecoder<S>());
    pipeline.addLast("ResponseHandler", new ServiceResponseHandler<S>(responseListeners,
        deserializer, executorService));
  }

  @Override
  protected void onFailure(String errorMessage, ChannelHandlerContext ctx, MessageEvent e) {
    log.error("Service client handshake failed: " + errorMessage);
    e.getChannel().close();
  }

  @Override
  public String getName() {
    return "ServiceClientHandshakeHandler";
  }
}