ActiveMQ example source code file (ConnectionPool.java)

This example ActiveMQ source code file (ConnectionPool.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, connectionpool, connectionpool, exception, io, jmsexception, jmsexception, map, objectpoolfactory, objectpoolfactory, sessionkey, sessionpool, sessionpool, transportlistener, util

The ActiveMQ ConnectionPool.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.io.IOException;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.concurrent.atomic.AtomicBoolean;

import javax.jms.JMSException;
import javax.jms.Session;

import org.apache.activemq.ActiveMQConnection;
import org.apache.activemq.transport.TransportListener;
import org.apache.commons.pool.ObjectPoolFactory;

/**
 * Holds a real JMS connection along with the session pools associated with it.
 * 
 * 
 */
public class ConnectionPool {

    private ActiveMQConnection connection;
    private Map<SessionKey, SessionPool> cache;
    private AtomicBoolean started = new AtomicBoolean(false);
    private int referenceCount;
    private ObjectPoolFactory poolFactory;
    private long lastUsed = System.currentTimeMillis();
    private long firstUsed = lastUsed;
    private boolean hasFailed;
    private boolean hasExpired;
    private int idleTimeout = 30 * 1000;
    private long expiryTimeout = 0l;

    public ConnectionPool(ActiveMQConnection connection, ObjectPoolFactory poolFactory) {
        this(connection, new HashMap<SessionKey, SessionPool>(), poolFactory);
        // Add a transport Listener so that we can notice if this connection
        // should be expired due to
        // a connection failure.
        connection.addTransportListener(new TransportListener() {
            public void onCommand(Object command) {
            }

            public void onException(IOException error) {
                synchronized (ConnectionPool.this) {
                    hasFailed = true;
                }
            }

            public void transportInterupted() {
            }

            public void transportResumed() {
            }
        });       
        //
        // make sure that we set the hasFailed flag, in case the transport already failed
        // prior to the addition of our new TransportListener
        //
        if(connection.isTransportFailed()) {
            hasFailed = true;
        }
    }

    public ConnectionPool(ActiveMQConnection connection, Map<SessionKey, SessionPool> cache, ObjectPoolFactory poolFactory) {
        this.connection = connection;
        this.cache = cache;
        this.poolFactory = poolFactory;
    }

    public void start() throws JMSException {
        if (started.compareAndSet(false, true)) {
        	try {
        		connection.start();
        	} catch (JMSException e) {
        		started.set(false);
        		throw(e);
        	}
        }
    }

    public synchronized ActiveMQConnection getConnection() {
        return connection;
    }

    public Session createSession(boolean transacted, int ackMode) throws JMSException {
        SessionKey key = new SessionKey(transacted, ackMode);
        SessionPool pool = cache.get(key);
        if (pool == null) {
            pool = createSessionPool(key);
            cache.put(key, pool);
        }
        PooledSession session = pool.borrowSession();
        return session;
    }

    public synchronized void close() {
        if (connection != null) {
            try {
                Iterator<SessionPool> i = cache.values().iterator();
                while (i.hasNext()) {
                    SessionPool pool = i.next();
                    i.remove();
                    try {
                        pool.close();
                    } catch (Exception e) {
                    }
                }
            } finally {
                try {
                    connection.close();
                } catch (Exception e) {
                } finally {
                    connection = null;
                }
            }
        }
    }

    public synchronized void incrementReferenceCount() {
        referenceCount++;
        lastUsed = System.currentTimeMillis();
    }

    public synchronized void decrementReferenceCount() {
        referenceCount--;
        lastUsed = System.currentTimeMillis();
        if (referenceCount == 0) {
            expiredCheck();
        }
    }

    /**
     * @return true if this connection has expired.
     */
    public synchronized boolean expiredCheck() {
        if (connection == null) {
            return true;
        }
        if (hasExpired) {
            if (referenceCount == 0) {
                close();
            }
            return true;
        }
        if (hasFailed 
                || (idleTimeout > 0 && System.currentTimeMillis() > lastUsed + idleTimeout)
                || expiryTimeout > 0 && System.currentTimeMillis() > firstUsed + expiryTimeout) {
            hasExpired = true;
            if (referenceCount == 0) {
                close();
            }
            return true;
        }
        return false;
    }

    public int getIdleTimeout() {
        return idleTimeout;
    }

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

    protected SessionPool createSessionPool(SessionKey key) {
        return new SessionPool(this, key, poolFactory.createPool());
    }

    public void setExpiryTimeout(long expiryTimeout) {
        this.expiryTimeout  = expiryTimeout;
    }
    
    public long getExpiryTimeout() {
        return expiryTimeout;
    }

}