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ActiveMQ example source code file (CommandAgent.java)

This example ActiveMQ source code file (CommandAgent.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

annotation, commandmessagelistener, connection, connection, connectionfactory, destination, destination, exception, jmsexception, jmsexception, logger, messageconsumer, servicestopper, string, string

The ActiveMQ CommandAgent.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 javax.annotation.PostConstruct;
import javax.annotation.PreDestroy;
import javax.jms.Connection;
import javax.jms.ConnectionFactory;
import javax.jms.Destination;
import javax.jms.ExceptionListener;
import javax.jms.JMSException;
import javax.jms.MessageConsumer;
import javax.jms.Session;
import org.apache.activemq.ActiveMQConnectionFactory;
import org.apache.activemq.Service;
import org.apache.activemq.advisory.AdvisorySupport;
import org.apache.activemq.util.ServiceStopper;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * An agent which listens to commands on a JMS destination
 * 
 * 
 * @org.apache.xbean.XBean
 */
public class CommandAgent implements Service, ExceptionListener {
    private static final Logger LOG = LoggerFactory.getLogger(CommandAgent.class);

    private String brokerUrl = "vm://localhost";
    private String username;
    private String password;
    private ConnectionFactory connectionFactory;
    private Connection connection;
    private Destination commandDestination;
    private CommandMessageListener listener;
    private Session session;
    private MessageConsumer consumer;

    /**
     *
     * @throws Exception
     * @org.apache.xbean.InitMethod
     */
    @PostConstruct
    public void start() throws Exception {
        session = getConnection().createSession(false, Session.AUTO_ACKNOWLEDGE);
        listener = new CommandMessageListener(session);
        Destination destination = getCommandDestination();
        if (LOG.isDebugEnabled()) {
            LOG.debug("Agent subscribing to control destination: " + destination);
        }
        consumer = session.createConsumer(destination);
        consumer.setMessageListener(listener);
    }

    /**
     *
     * @throws Exception
     * @org.apache.xbean.DestroyMethod
     */
    @PreDestroy
    public void stop() throws Exception {
        ServiceStopper stopper = new ServiceStopper();
        if (consumer != null) {
            try {
                consumer.close();
                consumer = null;
            } catch (JMSException e) {
                stopper.onException(this, e);
            }
        }
        if (session != null) {
            try {
                session.close();
                session = null;
            } catch (JMSException e) {
                stopper.onException(this, e);
            }
        }
        if (connection != null) {
            try {
                connection.close();
                connection = null;
            } catch (JMSException e) {
                stopper.onException(this, e);
            }
        }
        stopper.throwFirstException();
    }

    // Properties
    // -------------------------------------------------------------------------
    public String getBrokerUrl() {
        return brokerUrl;
    }

    public void setBrokerUrl(String brokerUrl) {
        this.brokerUrl = brokerUrl;
    }    

    public String getUsername() {
		return username;
	}

	public void setUsername(String username) {
		this.username = username;
	}

	public String getPassword() {
		return password;
	}

	public void setPassword(String password) {
		this.password = password;
	}

	public ConnectionFactory getConnectionFactory() {
        if (connectionFactory == null) {
            connectionFactory = new ActiveMQConnectionFactory(brokerUrl);
        }
        return connectionFactory;
    }

    public void setConnectionFactory(ConnectionFactory connectionFactory) {
        this.connectionFactory = connectionFactory;
    }

    public Connection getConnection() throws JMSException {
        if (connection == null) {
            connection = createConnection();
            connection.setExceptionListener(this);
            connection.start();
        }
        return connection;
    }

    public void setConnection(Connection connection) {
        this.connection = connection;
    }

    public Destination getCommandDestination() {
        if (commandDestination == null) {
            commandDestination = createCommandDestination();
        }
        return commandDestination;
    }

    public void setCommandDestination(Destination commandDestination) {
        this.commandDestination = commandDestination;
    }

    protected Connection createConnection() throws JMSException {
        return getConnectionFactory().createConnection(username, password);
    }

    protected Destination createCommandDestination() {
        return AdvisorySupport.getAgentDestination();
    }

    public void onException(JMSException exception) {
        try {
            stop();
        } catch (Exception e) {
        }
    }
}

Other ActiveMQ examples (source code examples)

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