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ActiveMQ example source code file (PooledConnectionFactory.java)

This example ActiveMQ source code file (PooledConnectionFactory.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

activemqconnection, atomicboolean, connection, connectionfactory, connectionkey, connectionpool, connectionpool, jmsexception, jmsexception, linkedlist, linkedlist, objectpoolfactory, pooledconnectionfactory, pooledconnectionfactory, util

The ActiveMQ PooledConnectionFactory.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.pool;

import java.util.HashMap;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.Map;
import java.util.concurrent.atomic.AtomicBoolean;
import javax.jms.Connection;
import javax.jms.ConnectionFactory;
import javax.jms.JMSException;
import org.apache.activemq.ActiveMQConnection;
import org.apache.activemq.ActiveMQConnectionFactory;
import org.apache.activemq.Service;
import org.apache.activemq.util.IOExceptionSupport;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.apache.commons.pool.ObjectPoolFactory;
import org.apache.commons.pool.impl.GenericObjectPoolFactory;

/**
 * A JMS provider which pools Connection, Session and MessageProducer instances
 * so it can be used with tools like <a href="http://camel.apache.org/activemq.html">Camel and Spring's .
 * Connections, sessions and producers are returned to a pool after use so that they can be reused later
 * without having to undergo the cost of creating them again.
 * 
 * b>NOTE:</b> while this implementation does allow the creation of a collection of active consumers,
 * it does not 'pool' consumers. Pooling makes sense for connections, sessions and producers, which 
 * are expensive to create and can remain idle a minimal cost. Consumers, on the other hand, are usually
 * just created at startup and left active, handling incoming messages as they come. When a consumer is
 * complete, it is best to close it rather than return it to a pool for later reuse: this is because, 
 * even if a consumer is idle, ActiveMQ will keep delivering messages to the consumer's prefetch buffer,
 * where they'll get held until the consumer is active again.
 * 
 * If you are creating a collection of consumers (for example, for multi-threaded message consumption), you
 * might want to consider using a lower prefetch value for each consumer (e.g. 10 or 20), to ensure that 
 * all messages don't end up going to just one of the consumers. See this FAQ entry for more detail: 
 * http://activemq.apache.org/i-do-not-receive-messages-in-my-second-consumer.html
 * 
 * @org.apache.xbean.XBean element="pooledConnectionFactory"
 * 
 * 
 */
public class PooledConnectionFactory implements ConnectionFactory, Service {
    private static final transient Logger LOG = LoggerFactory.getLogger(PooledConnectionFactory.class);
    private ConnectionFactory connectionFactory;
    private Map<ConnectionKey, LinkedList cache = new HashMap>();
    private ObjectPoolFactory poolFactory;
    private int maximumActive = 500;
    private int maxConnections = 1;
    private int idleTimeout = 30 * 1000;
    private AtomicBoolean stopped = new AtomicBoolean(false);
    private long expiryTimeout = 0l;

    public PooledConnectionFactory() {
        this(new ActiveMQConnectionFactory());
    }

    public PooledConnectionFactory(String brokerURL) {
        this(new ActiveMQConnectionFactory(brokerURL));
    }

    public PooledConnectionFactory(ActiveMQConnectionFactory connectionFactory) {
        this.connectionFactory = connectionFactory;
    }

    public ConnectionFactory getConnectionFactory() {
        return connectionFactory;
    }

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

    public Connection createConnection() throws JMSException {
        return createConnection(null, null);
    }

    public synchronized Connection createConnection(String userName, String password) throws JMSException {
        if (stopped.get()) {
            LOG.debug("PooledConnectionFactory is stopped, skip create new connection.");
            return null;
        }
        
        ConnectionKey key = new ConnectionKey(userName, password);
        LinkedList<ConnectionPool> pools = cache.get(key);

        if (pools == null) {
            pools = new LinkedList<ConnectionPool>();
            cache.put(key, pools);
        }

        ConnectionPool connection = null;
        if (pools.size() == maxConnections) {
            connection = pools.removeFirst();
        }

        // Now.. we might get a connection, but it might be that we need to
        // dump it..
        if (connection != null && connection.expiredCheck()) {
            connection = null;
        }

        if (connection == null) {
            ActiveMQConnection delegate = createConnection(key);
            connection = createConnectionPool(delegate);
        }
        pools.add(connection);
        return new PooledConnection(connection);
    }

    protected ConnectionPool createConnectionPool(ActiveMQConnection connection) {
        ConnectionPool result =  new ConnectionPool(connection, getPoolFactory());
        result.setIdleTimeout(getIdleTimeout());
        result.setExpiryTimeout(getExpiryTimeout());
        return result;
    }

    protected ActiveMQConnection createConnection(ConnectionKey key) throws JMSException {
        if (key.getUserName() == null && key.getPassword() == null) {
            return (ActiveMQConnection)connectionFactory.createConnection();
        } else {
            return (ActiveMQConnection)connectionFactory.createConnection(key.getUserName(), key.getPassword());
        }
    }

    /**
     * @see org.apache.activemq.service.Service#start()
     */
    public void start() {
        try {
            stopped.set(false);
            createConnection();
        } catch (JMSException e) {
            LOG.warn("Create pooled connection during start failed.", e);
            IOExceptionSupport.create(e);
        }
    }

    public void stop() {
        LOG.debug("Stop the PooledConnectionFactory, number of connections in cache: "+cache.size());
        stopped.set(true);
        for (Iterator<LinkedList iter = cache.values().iterator(); iter.hasNext();) {
            for (ConnectionPool connection : iter.next()) {
                try {
                    connection.close();
                }catch(Exception e) {
                    LOG.warn("Close connection failed",e);
                }
            }
        }
        cache.clear();
    }

    public ObjectPoolFactory getPoolFactory() {
        if (poolFactory == null) {
            poolFactory = createPoolFactory();
        }
        return poolFactory;
    }

    /**
     * Sets the object pool factory used to create individual session pools for
     * each connection
     */
    public void setPoolFactory(ObjectPoolFactory poolFactory) {
        this.poolFactory = poolFactory;
    }

    public int getMaximumActive() {
        return maximumActive;
    }

    /**
     * Sets the maximum number of active sessions per connection
     */
    public void setMaximumActive(int maximumActive) {
        this.maximumActive = maximumActive;
    }

    /**
     * @return the maxConnections
     */
    public int getMaxConnections() {
        return maxConnections;
    }

    /**
     * @param maxConnections the maxConnections to set
     */
    public void setMaxConnections(int maxConnections) {
        this.maxConnections = maxConnections;
    }

    protected ObjectPoolFactory createPoolFactory() {
        return new GenericObjectPoolFactory(null, maximumActive);
    }

    public int getIdleTimeout() {
        return idleTimeout;
    }

    public void setIdleTimeout(int idleTimeout) {
        this.idleTimeout = idleTimeout;
    }

    /**
     * allow connections to expire, irrespective of load or idle time. This is useful with failover
     * to force a reconnect from the pool, to reestablish load balancing or use of the master post recovery
     * 
     * @param expiryTimeout non zero in milliseconds
     */
    public void setExpiryTimeout(long expiryTimeout) {
        this.expiryTimeout = expiryTimeout;   
    }
    
    public long getExpiryTimeout() {
        return expiryTimeout;
    }
}
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