| /* |
| * 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.axis2.clustering.tribes; |
| |
| import org.apache.catalina.tribes.ChannelMessage; |
| import org.apache.catalina.tribes.group.ChannelInterceptorBase; |
| import org.apache.commons.logging.Log; |
| import org.apache.commons.logging.LogFactory; |
| |
| import java.util.ArrayList; |
| import java.util.HashMap; |
| import java.util.List; |
| import java.util.Map; |
| |
| /** |
| * Message intereceptor for handling at-most-once message processing semantics |
| */ |
| public class AtMostOnceInterceptor extends ChannelInterceptorBase { |
| |
| private static Log log = LogFactory.getLog(AtMostOnceInterceptor.class); |
| private static final Map<ChannelMessage, Long> receivedMessages = |
| new HashMap<ChannelMessage, Long>(); |
| |
| /** |
| * The time a message lives in the receivedMessages Map |
| */ |
| private static final int TIMEOUT = 5 * 60 * 1000; |
| |
| public AtMostOnceInterceptor() { |
| Thread cleanupThread = new Thread(new MessageCleanupTask()); |
| cleanupThread.setPriority(Thread.MIN_PRIORITY); |
| cleanupThread.start(); |
| } |
| |
| public void messageReceived(ChannelMessage msg) { |
| if (okToProcess(msg.getOptions())) { |
| synchronized (receivedMessages) { |
| if (receivedMessages.get(msg) == null) { // If it is a new message, keep track of it |
| receivedMessages.put(msg, System.currentTimeMillis()); |
| super.messageReceived(msg); |
| } else { // If it is a duplicate message, discard it. i.e. dont call super.messageReceived |
| log.info("Duplicate message received from " + TribesUtil.getName(msg.getAddress())); |
| } |
| } |
| } else { |
| super.messageReceived(msg); |
| } |
| } |
| |
| private class MessageCleanupTask implements Runnable { |
| |
| public void run() { |
| while (true) { // This task should never terminate |
| try { |
| Thread.sleep(TIMEOUT); |
| } catch (InterruptedException e) { |
| e.printStackTrace(); |
| } |
| try { |
| List<ChannelMessage> toBeRemoved = new ArrayList<ChannelMessage>(); |
| Thread.yield(); |
| synchronized (receivedMessages) { |
| for (ChannelMessage msg : receivedMessages.keySet()) { |
| long arrivalTime = receivedMessages.get(msg); |
| if (System.currentTimeMillis() - arrivalTime >= TIMEOUT) { |
| toBeRemoved.add(msg); |
| if (toBeRemoved.size() > 10000) { // Do not allow this thread to run for too long |
| break; |
| } |
| } |
| } |
| for (ChannelMessage msg : toBeRemoved) { |
| receivedMessages.remove(msg); |
| if (log.isDebugEnabled()) { |
| log.debug("Cleaned up message "); |
| } |
| } |
| } |
| } catch (Throwable e) { |
| log.error("Exception occurred while trying to cleanup messages", e); |
| } |
| } |
| } |
| } |
| } |