Java tutorial
/* * copyright 2012, gash * * Gash 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 snapchatproto.servers.management; import io.netty.channel.ChannelFuture; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import snapchatproto.servers.management.ManagementQueue.ManagementQueueEntry; public class OutboundMgmtWorker extends Thread { protected static Logger logger = LoggerFactory.getLogger("management"); int workerId; boolean forever = true; public OutboundMgmtWorker(ThreadGroup tgrp, int workerId) { super(tgrp, "outbound-mgmt-" + workerId); this.workerId = workerId; if (ManagementQueue.outbound == null) throw new RuntimeException("management worker detected null queue"); } @Override public void run() { while (true) { if (!forever && ManagementQueue.outbound.size() == 0) break; try { // block until a message is enqueued ManagementQueueEntry msg = ManagementQueue.outbound.take(); if (logger.isDebugEnabled()) logger.debug( "Outbound management message routing to node " + msg.req.getRaftHeader().getToNode()); if (msg.channel.isWritable()) { boolean rtn = false; if (msg.channel != null && msg.channel.isOpen() && msg.channel.isWritable()) { ChannelFuture cf = msg.channel.write(msg); // blocks on write - use listener to be async cf.awaitUninterruptibly(); rtn = cf.isSuccess(); if (!rtn) ManagementQueue.outbound.putFirst(msg); } } else { logger.info("channel to node " + msg.req.getRaftHeader().getToNode() + " is not writable"); ManagementQueue.outbound.putFirst(msg); } } catch (InterruptedException ie) { break; } catch (Exception e) { logger.error("Unexpected management communcation failure", e); break; } } if (!forever) { logger.info("management outbound queue closing"); } } }