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/*
* Copyright (C) 2013 Schlichtherle IT Services & Stimulus Software.
* All rights reserved. Use is subject to license terms.
*/
package net.java.trueupdate.jms;
import java.util.concurrent.*;
import javax.annotation.*;
import javax.annotation.concurrent.ThreadSafe;
import javax.jms.*;
import net.java.trueupdate.message.UpdateMessageListener;
import static net.java.trueupdate.util.Objects.requireNonNull;
import net.java.trueupdate.util.builder.AbstractBuilder;
/**
* Receives JMS messages in a loop and forwards them to the given
* {@link MessageListener}.
* This {@link Runnable} should be run by a {@link Thread} in environments
* where it's not possible to use
* {@link Session#setMessageListener(MessageListener)}, e.g. in a web app
* or an enterprise app, and it's not desirable to use a message driven
* bean.
*
* @author Christian Schlichtherle
*/
@ThreadSafe
public final class JmsReceiver implements Runnable {
public static final ThreadFactory LISTENER_THREAD_FACTORY =
new ThreadFactory() {
@Override public Thread newThread(Runnable r) {
return new Thread(r, "TrueUpdate JMS / Listener");
}
};
private static final boolean NO_LOCAL = true;
private final Object lock = new Object();
private final @Nullable String subscriptionName;
private final @CheckForNull String messageSelector;
private final MessageListener messageListener;
private final Destination destination;
private final ConnectionFactory connectionFactory;
private final ExecutorService executorService;
private Connection connection;
// Work around https://java.net/jira/browse/GLASSFISH-20836 .
private volatile Thread thread;
private JmsReceiver(final Builder b) {
this.subscriptionName = b.subscriptionName;
this.messageSelector = b.messageSelector;
this.messageListener = requireNonNull(b.messageListener);
this.destination = requireNonNull(b.destination);
this.connectionFactory = requireNonNull(b.connectionFactory);
this.executorService = requireNonNull(b.executorService);
}
/** Returns a new builder for JMS receivers. */
public static Builder builder() { return new Builder(); }
@Override public void run() {
try {
Connection c = null;
try {
MessageConsumer mc;
synchronized (lock) {
c = connection;
if (null != c)
throw new java.lang.IllegalStateException("Already running.");
c = connectionFactory.createConnection();
final Session s = c.createSession(false, Session.CLIENT_ACKNOWLEDGE);
final Destination d = destination;
mc = d instanceof Topic
? s.createDurableSubscriber((Topic) d, subscriptionName, messageSelector, NO_LOCAL)
: s.createConsumer(d, messageSelector);
thread = Thread.currentThread();
connection = c;
}
c.start();
while (true) {
final Message m = mc.receive();
if (null == m) break;
synchronized(lock) {
if (null == connection) break;
m.acknowledge();
executorService.execute(new Runnable() {
@Override public void run() {
messageListener.onMessage(m);
}
});
}
}
} finally {
if (null != c) {
// c.close(); // see https://issues.apache.org/jira/browse/AMQ-4769 .
synchronized (lock) {
thread = null;
lock.notifyAll();
}
}
}
} catch (JMSException ex) {
throw new java.lang.IllegalStateException(ex);
}
}
/** Stops this runnable from a different thread. */
public void stop(long timeout, TimeUnit unit) throws Exception {
// HC SVNT DRACONIS
// The following code is a fucking mess, but that's just because the
// JMS implementations Apache ActiveMQ 5.8.0 and Open MQ 5.0 are
// riddled with bugs - SCNR!
final long stop = System.currentTimeMillis() + unit.toMillis(timeout);
unit = TimeUnit.MILLISECONDS;
synchronized (lock) {
final Connection c = connection;
if (null == c) return;
connection = null;
// Work around https://java.net/jira/browse/GLASSFISH-20836 .
executorService.submit(new Runnable() {
@SuppressWarnings("SleepWhileInLoop")
@Override public void run() {
for (Thread t; null != (t = thread); ) {
// Wait first to give c.close() priority and avoid a
// JMSException with a wrapped InterruptedException
// when using ActiveMQ 5.8.0.
try { Thread.sleep(100); }
catch (InterruptedException stop) { }
t.interrupt();
}
}
});
try {
c.close();
} finally {
try {
timeout = Math.max(1, stop - System.currentTimeMillis());
lock.wait(timeout);
if (null != thread)
throw new TimeoutException();
} finally {
if (0 != executorService.shutdownNow().size())
throw new AssertionError();
timeout = Math.max(1, stop - System.currentTimeMillis());
if (!executorService.awaitTermination(timeout, unit))
throw new TimeoutException();
}
}
}
}
/**
* A builder for a JMS receiver.
*
* @param The type of the parent builder, if defined.
*/
@SuppressWarnings("PackageVisibleField")
public static class Builder
extends AbstractBuilder
{
@CheckForNull ConnectionFactory connectionFactory;
@CheckForNull Destination destination;
@CheckForNull String messageSelector, subscriptionName;
@CheckForNull MessageListener messageListener;
@CheckForNull ExecutorService executorService;
protected Builder() { }
public final Builder
connectionFactory(
final @Nullable ConnectionFactory connectionFactory) {
this.connectionFactory = connectionFactory;
return this;
}
public final Builder
destination(
final @Nullable Destination destination) {
this.destination = destination;
return this;
}
public final Builder
subscriptionName(
final @Nullable String subscriptionName) {
this.subscriptionName = subscriptionName;
return this;
}
public final Builder
messageSelector(
final @Nullable String messageSelector) {
this.messageSelector = messageSelector;
return this;
}
public final Builder
messageListener(
final @Nullable MessageListener messageListener) {
this.messageListener = messageListener;
return this;
}
public final Builder
updateMessageListener(
final @CheckForNull UpdateMessageListener updateMessageListener) {
this.messageListener = null == updateMessageListener
? null
: JmsListener.create(updateMessageListener);
return this;
}
public final Builder
executorService(
final @Nullable ExecutorService executorService) {
this.executorService = executorService;
return this;
}
@Override public final JmsReceiver build() {
return new JmsReceiver(this);
}
} // Builder
}