TcpClient.java

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/*
 * 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.transport.tcp;

import com.google.common.base.Preconditions;
import com.google.common.collect.Lists;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.jboss.netty.bootstrap.ClientBootstrap;
import org.jboss.netty.buffer.ChannelBuffer;
import org.jboss.netty.buffer.ChannelBufferFactory;
import org.jboss.netty.buffer.HeapChannelBufferFactory;
import org.jboss.netty.channel.Channel;
import org.jboss.netty.channel.ChannelFactory;
import org.jboss.netty.channel.ChannelFuture;
import org.jboss.netty.channel.ChannelPipeline;
import org.jboss.netty.channel.group.ChannelGroup;
import org.jboss.netty.channel.socket.nio.NioClientSocketChannelFactory;
import org.ros.exception.RosRuntimeException;

import java.net.SocketAddress;
import java.nio.ByteOrder;
import java.util.List;
import java.util.concurrent.Executor;
import java.util.concurrent.TimeUnit;

public class TcpClient {

  private static final boolean DEBUG = false;
  private static final Log log = LogFactory.getLog(TcpClient.class);

  private static final int DEFAULT_CONNECTION_TIMEOUT_DURATION = 5;
  private static final TimeUnit DEFAULT_CONNECTION_TIMEOUT_UNIT = TimeUnit.SECONDS;
  private static final boolean DEFAULT_KEEP_ALIVE = true;

  private final ChannelGroup channelGroup;
  private final ChannelFactory channelFactory;
  private final ChannelBufferFactory channelBufferFactory;
  private final ClientBootstrap bootstrap;
  private final List<NamedChannelHandler> namedChannelHandlers;
  
  private Channel channel;

  public TcpClient(ChannelGroup channelGroup, Executor executor) {
    this.channelGroup = channelGroup;
    channelFactory = new NioClientSocketChannelFactory(executor, executor);
    channelBufferFactory = new HeapChannelBufferFactory(ByteOrder.LITTLE_ENDIAN);
    bootstrap = new ClientBootstrap(channelFactory);
    bootstrap.setOption("bufferFactory", channelBufferFactory);
    setConnectionTimeout(DEFAULT_CONNECTION_TIMEOUT_DURATION, DEFAULT_CONNECTION_TIMEOUT_UNIT);
    setKeepAlive(DEFAULT_KEEP_ALIVE);
    namedChannelHandlers = Lists.newArrayList();
  }

  public void setConnectionTimeout(long duration, TimeUnit unit) {
    bootstrap.setOption("connectionTimeoutMillis", TimeUnit.MILLISECONDS.convert(duration, unit));
  }

  public void setKeepAlive(boolean value) {
    bootstrap.setOption("keepAlive", value);
  }

  public void addNamedChannelHandler(NamedChannelHandler namedChannelHandler) {
    namedChannelHandlers.add(namedChannelHandler);
  }

  public void addAllNamedChannelHandlers(List<NamedChannelHandler> namedChannelHandlers) {
    this.namedChannelHandlers.addAll(namedChannelHandlers);
  }

  public Channel connect(String connectionName, SocketAddress socketAddress) {
    TcpClientPipelineFactory tcpClientPipelineFactory = new TcpClientPipelineFactory(channelGroup) {
      @Override
      public ChannelPipeline getPipeline() {
        ChannelPipeline pipeline = super.getPipeline();
        for (NamedChannelHandler namedChannelHandler : namedChannelHandlers) {
          pipeline.addLast(namedChannelHandler.getName(), namedChannelHandler);
        }
        return pipeline;
      }
    };
    bootstrap.setPipelineFactory(tcpClientPipelineFactory);
    ChannelFuture future = bootstrap.connect(socketAddress).awaitUninterruptibly();
    if (future.isSuccess()) {
      channel = future.getChannel();
      if (DEBUG) {
        log.info("Connected to: " + socketAddress);
      }
    } else {
      // We expect the first connection to succeed. If not, fail fast.
      throw new RosRuntimeException("Connection exception: " + socketAddress, future.getCause());
    }
    return channel;
  }

  public ChannelFuture write(ChannelBuffer buffer) {
    Preconditions.checkNotNull(channel);
    Preconditions.checkNotNull(buffer);
    return channel.write(buffer);
  }
}