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 */ 017package org.apache.activemq.broker.region.policy; 018 019import java.util.ArrayList; 020import java.util.List; 021import org.apache.activemq.broker.Broker; 022import org.apache.activemq.broker.ConnectionContext; 023import org.apache.activemq.broker.region.MessageReference; 024import org.apache.activemq.broker.region.SubscriptionRecovery; 025import org.apache.activemq.broker.region.Topic; 026import org.apache.activemq.command.ActiveMQDestination; 027import org.apache.activemq.command.Message; 028import org.apache.activemq.filter.DestinationFilter; 029 030/** 031 * This implementation of {@link SubscriptionRecoveryPolicy} will only keep the 032 * last message. 033 * 034 * @org.apache.xbean.XBean 035 * 036 */ 037public class LastImageSubscriptionRecoveryPolicy implements SubscriptionRecoveryPolicy { 038 039 private volatile MessageReference lastImage; 040 041 public boolean add(ConnectionContext context, MessageReference node) throws Exception { 042 lastImage = node; 043 return true; 044 } 045 046 public void recover(ConnectionContext context, Topic topic, SubscriptionRecovery sub) throws Exception { 047 // Re-dispatch the last message seen. 048 MessageReference node = lastImage; 049 if (node != null) { 050 sub.addRecoveredMessage(context, node); 051 } 052 } 053 054 public void start() throws Exception { 055 } 056 057 public void stop() throws Exception { 058 } 059 060 public Message[] browse(ActiveMQDestination destination) throws Exception { 061 List<Message> result = new ArrayList<Message>(); 062 DestinationFilter filter = DestinationFilter.parseFilter(destination); 063 if (filter.matches(lastImage.getMessage().getDestination())) { 064 result.add(lastImage.getMessage()); 065 } 066 return result.toArray(new Message[result.size()]); 067 } 068 069 public SubscriptionRecoveryPolicy copy() { 070 return new LastImageSubscriptionRecoveryPolicy(); 071 } 072 073 public void setBroker(Broker broker) { 074 } 075 076}