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.concurrent.atomic.AtomicLong;
020import javax.jms.JMSException;
021import javax.jms.Message;
022import javax.jms.MessageListener;
023import org.apache.activemq.ActiveMQMessageTransformation;
024import org.apache.activemq.broker.Broker;
025import org.apache.activemq.broker.ConnectionContext;
026import org.apache.activemq.broker.region.Destination;
027import org.apache.activemq.broker.region.MessageReference;
028import org.apache.activemq.broker.region.SubscriptionRecovery;
029import org.apache.activemq.broker.region.Topic;
030import org.apache.activemq.command.ActiveMQDestination;
031import org.apache.activemq.command.ActiveMQMessage;
032import org.apache.activemq.command.ConnectionId;
033import org.apache.activemq.command.MessageId;
034import org.apache.activemq.command.ProducerId;
035import org.apache.activemq.command.SessionId;
036import org.apache.activemq.util.IdGenerator;
037import org.slf4j.Logger;
038import org.slf4j.LoggerFactory;
039
040/**
041 * This implementation of {@link SubscriptionRecoveryPolicy} will perform a user
042 * specific query mechanism to load any messages they may have missed.
043 * 
044 * @org.apache.xbean.XBean
045 * 
046 */
047public class QueryBasedSubscriptionRecoveryPolicy implements SubscriptionRecoveryPolicy {
048
049    private static final Logger LOG = LoggerFactory.getLogger(QueryBasedSubscriptionRecoveryPolicy.class);
050
051    private MessageQuery query;
052    private final AtomicLong messageSequence = new AtomicLong(0);
053    private final IdGenerator idGenerator = new IdGenerator();
054    private final ProducerId producerId = createProducerId();
055
056    public SubscriptionRecoveryPolicy copy() {
057        QueryBasedSubscriptionRecoveryPolicy rc = new QueryBasedSubscriptionRecoveryPolicy();
058        rc.setQuery(query);
059        return rc;
060    }
061
062    public boolean add(ConnectionContext context, MessageReference message) throws Exception {
063        return query.validateUpdate(message.getMessage());
064    }
065
066    public void recover(final ConnectionContext context, final Topic topic, final SubscriptionRecovery sub) throws Exception {
067        if (query != null) {
068            ActiveMQDestination destination = sub.getActiveMQDestination();
069            query.execute(destination, new MessageListener() {
070
071                public void onMessage(Message message) {
072                    dispatchInitialMessage(message, topic, context, sub);
073                }
074            });
075        }
076    }
077
078    public void start() throws Exception {
079        if (query == null) {
080            throw new IllegalArgumentException("No query property configured");
081        }
082    }
083
084    public void stop() throws Exception {
085    }
086
087    public MessageQuery getQuery() {
088        return query;
089    }
090
091    /**
092     * Sets the query strategy to load initial messages
093     */
094    public void setQuery(MessageQuery query) {
095        this.query = query;
096    }
097
098    public org.apache.activemq.command.Message[] browse(ActiveMQDestination dest) throws Exception {
099        return new org.apache.activemq.command.Message[0];
100    }
101    
102    public void setBroker(Broker broker) {        
103    }
104
105    protected void dispatchInitialMessage(Message message, Destination regionDestination, ConnectionContext context, SubscriptionRecovery sub) {
106        try {
107            ActiveMQMessage activeMessage = ActiveMQMessageTransformation.transformMessage(message, null);
108            ActiveMQDestination destination = activeMessage.getDestination();
109            if (destination == null) {
110                destination = sub.getActiveMQDestination();
111                activeMessage.setDestination(destination);
112            }
113            activeMessage.setRegionDestination(regionDestination);
114            configure(activeMessage);
115            sub.addRecoveredMessage(context, activeMessage);
116        } catch (Throwable e) {
117            LOG.warn("Failed to dispatch initial message: {} into subscription. Reason: ", message, e);
118        }
119    }
120
121    protected void configure(ActiveMQMessage msg) throws JMSException {
122        long sequenceNumber = messageSequence.incrementAndGet();
123        msg.setMessageId(new MessageId(producerId, sequenceNumber));
124        msg.onSend();
125        msg.setProducerId(producerId);
126    }
127
128    protected ProducerId createProducerId() {
129        String id = idGenerator.generateId();
130        ConnectionId connectionId = new ConnectionId(id);
131        SessionId sessionId = new SessionId(connectionId, 1);
132        return new ProducerId(sessionId, 1);
133    }
134}