BrowseDestinationTask.java

/* 
 * Copyright 2003,2004 Colin Crist
 *
 * 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 hermes.browser.tasks;

import hermes.BrowseInterruptedException;
import hermes.Domain;
import hermes.Hermes;
import hermes.browser.HermesBrowser;
import hermes.browser.IconCache;
import hermes.config.DestinationConfig;
import hermes.impl.QueueBrowserWithConsumer;

import java.util.Enumeration;
import java.util.Iterator;

import javax.jms.Destination;
import javax.jms.JMSException;
import javax.jms.Message;
import javax.jms.Queue;
import javax.jms.QueueBrowser;

import org.apache.log4j.Logger;

/**
 * @author colincrist@hermesjms.com
 */
public class BrowseDestinationTask extends TaskSupport implements Task {
	private static final Logger log = Logger.getLogger(BrowseDestinationTask.class);
	private Hermes hermes;
	private Iterator iter;
	private QueueBrowser browser;
	private String title = "Browse";
	private boolean useMessageConsumer = false;
	private boolean queuesOnly = false;

	public BrowseDestinationTask(Hermes hermes, final DestinationConfig dConfig) {
		super(Domain.getDomain(dConfig.getDomain()).getIcon());

		this.hermes = hermes;
		this.title = "Browsing " + dConfig.getName() + " on " + hermes.getId();

		if (dConfig.isDurable()) {
			title = title + " (durableName=" + dConfig.getClientID() + ")";
		}

		this.iter = new Iterator() {
			private boolean first = true;

			public void remove() {
				// TODO Auto-generated method stub
			}

			public boolean hasNext() {
				return first;
			}

			public Object next() {
				first = false;
				return dConfig;
			}
		};
	}

	public BrowseDestinationTask(Hermes hermes, Iterator iter) {
		super(IconCache.getIcon("jms.unknown"));

		this.hermes = hermes;
		this.iter = iter;
		this.queuesOnly = true; // Can only browse queues when browsing all destinations on a session. 
	}

	public String getTitle() {
		return title;
	}

	protected QueueBrowser createBrowser(Destination destination, DestinationConfig dConfig) throws JMSException {
		if (dConfig.getDomain() == Domain.QUEUE.getId() && hermes.getSessionConfig().isUseConsumerForQueueBrowse()) {
			log.debug("using a MessageConsumer for the QueueBrowse");

			return new QueueBrowserWithConsumer(hermes, (Queue) destination, dConfig.getSelector(), HermesBrowser.getBrowser().getQueueBrowseConsumerTimeout());
		} else {
			return hermes.createBrowser(dConfig);
		}
	}

	public void stop() {
		super.stop();

		try {
			if (browser != null) {
				browser.close();
				browser = null;
			}
		} catch (JMSException e) {
			log.error(e.getMessage(), e);
		}
	}

	public void invoke() throws Exception {
		while (iter.hasNext()) {
			final DestinationConfig dConfig = (DestinationConfig) iter.next();
			final boolean shouldBrowse = queuesOnly ? Domain.getDomain(dConfig.getDomain()).equals(Domain.QUEUE) : true ;
			int nmessages = 0;

			try {
				if (shouldBrowse) {
					final Destination destination = hermes.getDestination(dConfig.getName(), Domain.getDomain(dConfig.getDomain()));
					browser = createBrowser(destination, dConfig);

					notifyStatus("Running...");

					for (final Enumeration messageIter = browser.getEnumeration(); messageIter.hasMoreElements() && isRunning();) {
						final Message message = (Message) messageIter.nextElement();

						if (message != null) {
							notifyMessage(message);
							nmessages++;
						} else {
							// @TODO May be a bug here, keep an eye out for this
							// message recurring!

							log.error("Got a null message!");
							Thread.sleep(500);
						}
					}

					if (!isRunning()) {
						log.debug("user requested stop browse of " + dConfig.getName());
					}
				}
			} catch (BrowseInterruptedException ex) {
				log.info("browse of " + getTitle() + " interrupted after " + nmessages);
			} catch (InterruptedException ex) {
				log.info(ex.getMessage(), ex);
			} finally {
				log.debug("browse complete nmessages=" + nmessages);

				notifyStatus("Done.");

				if (browser != null) {
					browser.close();
					browser = null;
				}

				hermes.close();
			}
		}
	}

	public boolean isUseMessageConsumer() {
		return useMessageConsumer;
	}

	public void setUseMessageConsumer(boolean useMessageConsumer) {
		this.useMessageConsumer = useMessageConsumer;
	}
}