001 /** 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017 package org.apache.activemq.broker.region.policy; 018 019 import java.util.ArrayList; 020 import java.util.List; 021 import org.apache.activemq.broker.ConnectionContext; 022 import org.apache.activemq.broker.region.MessageReference; 023 import org.apache.activemq.broker.region.SubscriptionRecovery; 024 import org.apache.activemq.broker.region.Topic; 025 import org.apache.activemq.command.ActiveMQDestination; 026 import org.apache.activemq.command.Message; 027 import org.apache.activemq.filter.DestinationFilter; 028 029 /** 030 * This implementation of {@link SubscriptionRecoveryPolicy} will only keep the 031 * last message. 032 * 033 * @org.apache.xbean.XBean 034 * @version $Revision$ 035 */ 036 public class LastImageSubscriptionRecoveryPolicy implements SubscriptionRecoveryPolicy { 037 038 private volatile MessageReference lastImage; 039 040 public boolean add(ConnectionContext context, MessageReference node) throws Exception { 041 lastImage = node; 042 return true; 043 } 044 045 public void recover(ConnectionContext context, Topic topic, SubscriptionRecovery sub) throws Exception { 046 // Re-dispatch the last message seen. 047 MessageReference node = lastImage; 048 if (node != null) { 049 sub.addRecoveredMessage(context, node); 050 } 051 } 052 053 public void start() throws Exception { 054 } 055 056 public void stop() throws Exception { 057 } 058 059 public Message[] browse(ActiveMQDestination destination) throws Exception { 060 List<Message> result = new ArrayList<Message>(); 061 DestinationFilter filter = DestinationFilter.parseFilter(destination); 062 if (filter.matches(lastImage.getMessage().getDestination())) { 063 result.add(lastImage.getMessage()); 064 } 065 return result.toArray(new Message[result.size()]); 066 } 067 068 public SubscriptionRecoveryPolicy copy() { 069 return new LastImageSubscriptionRecoveryPolicy(); 070 } 071 072 }