@Override
protected void doShutdown() {
if (!this.isRunning()) {
return;
}
try {
synchronized (consumersMonitor) {
if (this.consumers != null) {
for (BlockingQueueConsumer consumer : this.consumers.keySet()) {
consumer.setQuiesce(this.shutdownTimeout);
}
}
}
logger.info("Waiting for workers to finish.");
boolean finished = cancellationLock.await(shutdownTimeout, TimeUnit.MILLISECONDS);
if (finished) {
logger.info("Successfully waited for workers to finish.");
} else {
logger.info("Workers not finished. Forcing connections to close.");
}
} catch (InterruptedException e) {
Thread.currentThread().interrupt();
logger.warn("Interrupted waiting for workers. Continuing with shutdown.");
}
synchronized (this.consumersMonitor) {
this.consumers = null;
}
}
/**
* Specify the number of concurrent consumers to create. Default is 1.
*
* <p>Raising the number of concurrent consumers is recommended in order to scale the consumption
* of messages coming in from a queue. However, note that any ordering guarantees are lost once
* multiple consumers are registered. In general, stick with 1 consumer for low-volume queues.
* Cannot be less than {@link #maxConcurrentConsumers} (if set).
*
* @see #setMaxConcurrentConsumers(int)
* @param concurrentConsumers the minimum number of consumers to create.
*/
public void setConcurrentConsumers(final int concurrentConsumers) {
Assert.isTrue(concurrentConsumers > 0, "'concurrentConsumers' value must be at least 1 (one)");
if (this.maxConcurrentConsumers != null) {
Assert.isTrue(
concurrentConsumers <= this.maxConcurrentConsumers,
"'concurrentConsumers' cannot be more than 'maxConcurrentConsumers'");
}
synchronized (consumersMonitor) {
if (logger.isDebugEnabled()) {
logger.debug(
"Changing consumers from " + this.concurrentConsumers + " to " + concurrentConsumers);
}
int delta = this.concurrentConsumers - concurrentConsumers;
this.concurrentConsumers = concurrentConsumers;
if (isActive() && this.consumers != null) {
if (delta > 0) {
Iterator<Entry<BlockingQueueConsumer, Boolean>> entryIterator =
consumers.entrySet().iterator();
while (entryIterator.hasNext() && delta > 0) {
Entry<BlockingQueueConsumer, Boolean> entry = entryIterator.next();
if (entry.getValue()) {
BlockingQueueConsumer consumer = entry.getKey();
consumer.setQuiesce(this.shutdownTimeout);
this.consumers.put(consumer, false);
delta--;
}
}
} else {
addAndStartConsumers(-delta);
}
}
}
}
