| /* |
| * 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.giraph.comm.netty; |
| |
| import java.net.InetSocketAddress; |
| import java.util.List; |
| import com.google.common.collect.Lists; |
| |
| import io.netty.channel.Channel; |
| import io.netty.channel.ChannelFuture; |
| import io.netty.channel.ChannelFutureListener; |
| import org.apache.log4j.Logger; |
| |
| |
| /** |
| * Maintains multiple channels and rotates between them. This is thread-safe. |
| */ |
| public class ChannelRotater { |
| /** Logger */ |
| private static final Logger LOG = Logger.getLogger(ChannelRotater.class); |
| /** Index of last used channel */ |
| private int index = 0; |
| /** Channel list */ |
| private final List<Channel> channelList = Lists.newArrayList(); |
| /** Task id of this channel */ |
| private final Integer taskId; |
| /** Address these channels are associated with */ |
| private final InetSocketAddress address; |
| |
| /** |
| * Constructor |
| * |
| * @param taskId Id of the task these channels as associated with |
| * @param address Address these channels are associated with |
| */ |
| public ChannelRotater(Integer taskId, InetSocketAddress address) { |
| this.taskId = taskId; |
| this.address = address; |
| } |
| |
| public Integer getTaskId() { |
| return taskId; |
| } |
| |
| /** |
| * Add a channel to the rotation |
| * |
| * @param channel Channel to add |
| */ |
| public synchronized void addChannel(Channel channel) { |
| synchronized (channelList) { |
| channelList.add(channel); |
| } |
| } |
| |
| /** |
| * Get the next channel |
| * |
| * @return Next channel |
| */ |
| public synchronized Channel nextChannel() { |
| if (channelList.isEmpty()) { |
| LOG.warn("nextChannel: No channels exist for hostname " + |
| address.getHostName()); |
| return null; |
| } |
| |
| ++index; |
| if (index >= channelList.size()) { |
| index = 0; |
| } |
| return channelList.get(index); |
| } |
| |
| /** |
| * Remove the a channel |
| * |
| * @param channel Channel to remove |
| * @return Return true if successful, false otherwise |
| */ |
| public synchronized boolean removeChannel(Channel channel) { |
| boolean success = channelList.remove(channel); |
| if (index >= channelList.size()) { |
| index = 0; |
| } |
| return success; |
| } |
| |
| /** |
| * Get the number of channels in this object |
| * |
| * @return Number of channels |
| */ |
| public synchronized int size() { |
| return channelList.size(); |
| } |
| |
| /** |
| * Close the channels |
| * |
| * @param channelFutureListener If desired, pass in a channel future listener |
| */ |
| public synchronized void closeChannels( |
| ChannelFutureListener channelFutureListener) { |
| for (Channel channel : channelList) { |
| ChannelFuture channelFuture = channel.close(); |
| if (channelFutureListener != null) { |
| channelFuture.addListener(channelFutureListener); |
| } |
| } |
| } |
| |
| /** |
| * Get a copy of the channels |
| * |
| * @return Copy of the channels |
| */ |
| public synchronized Iterable<Channel> getChannels() { |
| return Lists.newArrayList(channelList); |
| } |
| } |