/**
*
* Copyright 2004 Protique Ltd
*
* Licensed 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.codehaus.activemq.service.impl;
import EDU.oswego.cs.dl.util.concurrent.ConcurrentHashMap;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.codehaus.activemq.broker.BrokerClient;
import org.codehaus.activemq.message.ActiveMQMessage;
import org.codehaus.activemq.service.MessageContainerManager;
import org.codehaus.activemq.service.Service;
import org.codehaus.activemq.service.Subscription;
import javax.jms.JMSException;
import java.util.Map;
import java.util.Iterator;
/**
* A Dispatcher that polls for updates for active Message Consumers
*
* @version $Revision: 1.9 $
*/
public class DispatchWorker implements Runnable, Service {
private static final Log log = LogFactory.getLog(DispatchWorker.class);
private static final int POLL_TIMEOUT = 250;
private Map subscriptions = new ConcurrentHashMap(1000, 0.75f);
private Object lock = new Object();
private boolean active = true;
private boolean started = false;
private MessageContainerManager containerManager;
/**
* Register the MessageContainerManager for the Dispatcher
*
* @param mcm
*/
public void register(MessageContainerManager mcm) {
this.containerManager = mcm;
}
/**
* Called to indicate that there is work to do on a Subscription this will wake up a Dispatch Worker if it is
* waiting for messages to dispatch
*/
public void wakeup() {
synchronized (lock) {
active = true;
lock.notifyAll();
}
}
/**
* Add an active subscription
*
* @param client
* @param sub
*/
public void addActiveSubscription(BrokerClient client, Subscription sub) {
if (log.isDebugEnabled()) {
log.info("Adding subscription: " + sub + " to client: " + client);
}
subscriptions.put(sub, client);
}
/**
* remove an active subscription
*
* @param client
* @param sub
*/
public void removeActiveSubscription(BrokerClient client, Subscription sub) {
if (log.isDebugEnabled()) {
log.info("Removing subscription: " + sub + " from client: " + client);
}
subscriptions.remove(sub);
}
/**
* dispatch messages to active Consumers
*
* @see java.lang.Runnable#run()
*/
public void run() {
while (started) {
doPoll();
boolean dispatched = false;
try {
// our collection will not throw concurrent modification exception
for (Iterator iter = subscriptions.keySet().iterator(); iter.hasNext();) {
Subscription sub = (Subscription) iter.next();
if (sub != null && sub.isReadyToDispatch()) {
dispatched = dispatchMessages(sub, dispatched);
}
}
}
catch (JMSException jmsEx) {
log.error("Could not dispatch to Subscription: " + jmsEx, jmsEx);
}
if (!dispatched) {
synchronized (lock) {
active = false;
if (!active && started) {
try {
lock.wait(POLL_TIMEOUT);
}
catch (InterruptedException e) {
}
}
}
}
}
}
/**
* start the DispatchWorker
*
* @see org.codehaus.activemq.service.Service#start()
*/
public void start() {
started = true;
}
/**
* stop the DispatchWorker
*
* @see org.codehaus.activemq.service.Service#stop()
*/
public void stop() {
started = false;
}
// Implementation methods
//-------------------------------------------------------------------------
protected boolean dispatchMessages(Subscription subscription, boolean dispatched) throws JMSException {
ActiveMQMessage[] msgs = subscription.getMessagesToDispatch();
if (msgs != null && msgs.length > 0) {
BrokerClient client = (BrokerClient) subscriptions.get(subscription);
if (client == null) {
log.warn("Null client for subscription: " + subscription);
}
else {
for (int i = 0; i < msgs.length; i++) {
ActiveMQMessage msg = msgs[i].shallowCopy();
if (log.isDebugEnabled()) {
log.debug("Dispatching message: " + msg);
}
int[] consumerNos = new int[1];
consumerNos[0] = subscription.getConsumerNumber();
msg.setConsumerNos(consumerNos);
client.dispatch(msg);
dispatched = true;
}
}
}
return dispatched;
}
protected void doPoll() {
if (containerManager != null && started) {
try {
containerManager.poll();
}
catch (JMSException e) {
log.error("Error polling from the ContainerManager: ", e);
}
}
}
}