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ActiveMQ example source code file (TimeStampingBrokerPlugin.java)

This example ActiveMQ source code file (TimeStampingBrokerPlugin.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

brokerpluginsupport, brokerpluginsupport, exception, exception, log, logger, message, message, override, set, timestampingbrokerplugin, timestampingbrokerplugin

The ActiveMQ TimeStampingBrokerPlugin.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.util;

import org.apache.activemq.broker.BrokerPluginSupport;
import org.apache.activemq.broker.ProducerBrokerExchange;
import org.apache.activemq.command.Message;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * A Broker interceptor which updates a JMS Client's timestamp on the message
 * with a broker timestamp. Useful when the clocks on client machines are known
 * to not be correct and you can only trust the time set on the broker machines.
 * 
 * Enabling this plugin will break JMS compliance since the timestamp that the
 * producer sees on the messages after as send() will be different from the
 * timestamp the consumer will observe when he receives the message. This plugin
 * is not enabled in the default ActiveMQ configuration.
 * 
 * 2 new attributes have been added which will allow the administrator some override control
 * over the expiration time for incoming messages:
 *
 * Attribute 'zeroExpirationOverride' can be used to apply an expiration
 * time to incoming messages with no expiration defined (messages that would never expire)
 *
 * Attribute 'ttlCeiling' can be used to apply a limit to the expiration time
 *
 * @org.apache.xbean.XBean element="timeStampingBrokerPlugin"
 * 
 * 
 */
public class TimeStampingBrokerPlugin extends BrokerPluginSupport {
    private static final Logger LOG = LoggerFactory.getLogger(TimeStampingBrokerPlugin.class);
    /** 
    * variable which (when non-zero) is used to override
    * the expiration date for messages that arrive with
    * no expiration date set (in Milliseconds).
    */
    long zeroExpirationOverride = 0;

    /** 
    * variable which (when non-zero) is used to limit
    * the expiration date (in Milliseconds).  
    */
    long ttlCeiling = 0;
    
    /**
     * If true, the plugin will not update timestamp to past values
     * False by default
     */
    boolean futureOnly = false;
    
    
    /**
     * if true, update timestamp even if message has passed through a network
     * default false
     */
    boolean processNetworkMessages = false;

    /** 
    * setter method for zeroExpirationOverride
    */
    public void setZeroExpirationOverride(long ttl)
    {
        this.zeroExpirationOverride = ttl;
    }

    /** 
    * setter method for ttlCeiling
    */
    public void setTtlCeiling(long ttlCeiling)
    {
        this.ttlCeiling = ttlCeiling;
    }

	public void setFutureOnly(boolean futureOnly) {
		this.futureOnly = futureOnly;
	}
	
	public void setProcessNetworkMessages(Boolean processNetworkMessages) {
	    this.processNetworkMessages = processNetworkMessages;
	}

	@Override
    public void send(ProducerBrokerExchange producerExchange, Message message) throws Exception {
        if (message.getTimestamp() > 0
            && (processNetworkMessages || (message.getBrokerPath() == null || message.getBrokerPath().length == 0))) {
            // timestamp not been disabled and has not passed through a network or processNetworkMessages=true
            long oldExpiration = message.getExpiration();
            long newTimeStamp = System.currentTimeMillis();
            long timeToLive = zeroExpirationOverride;
            long oldTimestamp = message.getTimestamp();
            if (oldExpiration > 0) {
                timeToLive = oldExpiration - oldTimestamp;
            }
            if (timeToLive > 0 && ttlCeiling > 0 && timeToLive > ttlCeiling) {
                timeToLive = ttlCeiling;
            }
            long expiration = timeToLive + newTimeStamp;
			//In the scenario that the Broker is behind the clients we never want to set the Timestamp and Expiration in the past 
			if(!futureOnly || (expiration > oldExpiration)) {
				if (timeToLive > 0 && expiration > 0) {
					message.setExpiration(expiration);
				}
				message.setTimestamp(newTimeStamp);
				if (LOG.isDebugEnabled()) {
				    LOG.debug("Set message " + message.getMessageId() + " timestamp from " + oldTimestamp + " to " + newTimeStamp);
				}
			}
        }
        super.send(producerExchange, message);
    }
}

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