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ActiveMQ example source code file (QueryBasedSubscriptionRecoveryPolicy.java)

This example ActiveMQ source code file (QueryBasedSubscriptionRecoveryPolicy.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - ActiveMQ tags/keywords

activemqdestination, atomiclong, connectionid, connectionid, exception, exception, idgenerator, messagequery, producerid, producerid, querybasedsubscriptionrecoverypolicy, querybasedsubscriptionrecoverypolicy, subscriptionrecovery, subscriptionrecoverypolicy

The ActiveMQ QueryBasedSubscriptionRecoveryPolicy.java source code

/**
 * 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.activemq.broker.region.policy;

import java.util.concurrent.atomic.AtomicLong;
import javax.jms.JMSException;
import javax.jms.Message;
import javax.jms.MessageListener;
import org.apache.activemq.ActiveMQMessageTransformation;
import org.apache.activemq.broker.Broker;
import org.apache.activemq.broker.ConnectionContext;
import org.apache.activemq.broker.region.Destination;
import org.apache.activemq.broker.region.MessageReference;
import org.apache.activemq.broker.region.SubscriptionRecovery;
import org.apache.activemq.broker.region.Topic;
import org.apache.activemq.command.ActiveMQDestination;
import org.apache.activemq.command.ActiveMQMessage;
import org.apache.activemq.command.ConnectionId;
import org.apache.activemq.command.MessageId;
import org.apache.activemq.command.ProducerId;
import org.apache.activemq.command.SessionId;
import org.apache.activemq.util.IdGenerator;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * This implementation of {@link SubscriptionRecoveryPolicy} will perform a user
 * specific query mechanism to load any messages they may have missed.
 * 
 * @org.apache.xbean.XBean
 * 
 */
public class QueryBasedSubscriptionRecoveryPolicy implements SubscriptionRecoveryPolicy {

    private static final Logger LOG = LoggerFactory.getLogger(QueryBasedSubscriptionRecoveryPolicy.class);

    private MessageQuery query;
    private final AtomicLong messageSequence = new AtomicLong(0);
    private final IdGenerator idGenerator = new IdGenerator();
    private final ProducerId producerId = createProducerId();

    public SubscriptionRecoveryPolicy copy() {
        QueryBasedSubscriptionRecoveryPolicy rc = new QueryBasedSubscriptionRecoveryPolicy();
        rc.setQuery(query);
        return rc;
    }

    public boolean add(ConnectionContext context, MessageReference message) throws Exception {
        return query.validateUpdate(message.getMessage());
    }

    public void recover(final ConnectionContext context, final Topic topic, final SubscriptionRecovery sub) throws Exception {
        if (query != null) {
            ActiveMQDestination destination = sub.getActiveMQDestination();
            query.execute(destination, new MessageListener() {

                public void onMessage(Message message) {
                    dispatchInitialMessage(message, topic, context, sub);
                }
            });
        }
    }

    public void start() throws Exception {
        if (query == null) {
            throw new IllegalArgumentException("No query property configured");
        }
    }

    public void stop() throws Exception {
    }

    public MessageQuery getQuery() {
        return query;
    }

    /**
     * Sets the query strategy to load initial messages
     */
    public void setQuery(MessageQuery query) {
        this.query = query;
    }

    public org.apache.activemq.command.Message[] browse(ActiveMQDestination dest) throws Exception {
        return new org.apache.activemq.command.Message[0];
    }
    
    public void setBroker(Broker broker) {        
    }

    protected void dispatchInitialMessage(Message message, Destination regionDestination, ConnectionContext context, SubscriptionRecovery sub) {
        try {
            ActiveMQMessage activeMessage = ActiveMQMessageTransformation.transformMessage(message, null);
            ActiveMQDestination destination = activeMessage.getDestination();
            if (destination == null) {
                destination = sub.getActiveMQDestination();
                activeMessage.setDestination(destination);
            }
            activeMessage.setRegionDestination(regionDestination);
            configure(activeMessage);
            sub.addRecoveredMessage(context, activeMessage);
        } catch (Throwable e) {
            LOG.warn("Failed to dispatch initial message: " + message + " into subscription. Reason: " + e, e);
        }
    }

    protected void configure(ActiveMQMessage msg) throws JMSException {
        long sequenceNumber = messageSequence.incrementAndGet();
        msg.setMessageId(new MessageId(producerId, sequenceNumber));
        msg.onSend();
        msg.setProducerId(producerId);
    }

    protected ProducerId createProducerId() {
        String id = idGenerator.generateId();
        ConnectionId connectionId = new ConnectionId(id);
        SessionId sessionId = new SessionId(connectionId, 1);
        return new ProducerId(sessionId, 1);
    }
}

Other ActiveMQ examples (source code examples)

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