/**
* 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.camel.component.disruptor;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.TimeUnit;
import com.lmax.disruptor.InsufficientCapacityException;
import org.apache.camel.AsyncCallback;
import org.apache.camel.Exchange;
import org.apache.camel.ExchangeTimedOutException;
import org.apache.camel.WaitForTaskToComplete;
import org.apache.camel.impl.DefaultAsyncProducer;
import org.apache.camel.support.SynchronizationAdapter;
import org.apache.camel.util.ExchangeHelper;
/**
* A Producer for the Disruptor component.
*/
public class DisruptorProducer extends DefaultAsyncProducer {
private final WaitForTaskToComplete waitForTaskToComplete;
private final long timeout;
private final DisruptorEndpoint endpoint;
private boolean blockWhenFull;
public DisruptorProducer(final DisruptorEndpoint endpoint,
final WaitForTaskToComplete waitForTaskToComplete,
final long timeout, boolean blockWhenFull) {
super(endpoint);
this.waitForTaskToComplete = waitForTaskToComplete;
this.timeout = timeout;
this.endpoint = endpoint;
this.blockWhenFull = blockWhenFull;
}
@Override
public DisruptorEndpoint getEndpoint() {
return endpoint;
}
@Override
protected void doStart() throws Exception {
getEndpoint().onStarted(this);
}
@Override
protected void doStop() throws Exception {
getEndpoint().onStopped(this);
}
@Override
public boolean process(final Exchange exchange, final AsyncCallback callback) {
WaitForTaskToComplete wait = waitForTaskToComplete;
if (exchange.getProperty(Exchange.ASYNC_WAIT) != null) {
wait = exchange.getProperty(Exchange.ASYNC_WAIT, WaitForTaskToComplete.class);
}
if (wait == WaitForTaskToComplete.Always
|| (wait == WaitForTaskToComplete.IfReplyExpected && ExchangeHelper.isOutCapable(exchange))) {
// do not handover the completion as we wait for the copy to complete, and copy its result back when it done
final Exchange copy = prepareCopy(exchange, false);
// latch that waits until we are complete
final CountDownLatch latch = new CountDownLatch(1);
// we should wait for the reply so install a on completion so we know when its complete
copy.addOnCompletion(new SynchronizationAdapter() {
@Override
public void onDone(final Exchange response) {
// check for timeout, which then already would have invoked the latch
if (latch.getCount() == 0) {
if (log.isTraceEnabled()) {
log.trace("{}. Timeout occurred so response will be ignored: {}", this,
response.hasOut() ? response.getOut() : response.getIn());
}
} else {
if (log.isTraceEnabled()) {
log.trace("{} with response: {}", this,
response.hasOut() ? response.getOut() : response.getIn());
}
try {
ExchangeHelper.copyResults(exchange, response);
} finally {
// always ensure latch is triggered
latch.countDown();
}
}
}
@Override
public boolean allowHandover() {
// do not allow handover as we want to seda producer to have its completion triggered
// at this point in the routing (at this leg), instead of at the very last (this ensure timeout is honored)
return false;
}
@Override
public String toString() {
return "onDone at endpoint: " + endpoint;
}
});
doPublish(copy);
if (timeout > 0) {
if (log.isTraceEnabled()) {
log.trace("Waiting for task to complete using timeout (ms): {} at [{}]", timeout,
endpoint.getEndpointUri());
}
// lets see if we can get the task done before the timeout
boolean done = false;
try {
done = latch.await(timeout, TimeUnit.MILLISECONDS);
} catch (InterruptedException e) {
// ignore
}
if (!done) {
// Remove timed out Exchange from disruptor endpoint.
// We can't actually remove a published exchange from an active Disruptor.
// Instead we prevent processing of the exchange by setting a Property on the exchange and the value
// would be an AtomicBoolean. This is set by the Producer and the Consumer would look up that Property and
// check the AtomicBoolean. If the AtomicBoolean says that we are good to proceed, it will process the
// exchange. If false, it will simply disregard the exchange.
// But since the Property map is a Concurrent one, maybe we don't need the AtomicBoolean. Check with Simon.
// Also check the TimeoutHandler of the new Disruptor 3.0.0, consider making the switch to the latest version.
exchange.setProperty(DisruptorEndpoint.DISRUPTOR_IGNORE_EXCHANGE, true);
exchange.setException(new ExchangeTimedOutException(exchange, timeout));
// count down to indicate timeout
latch.countDown();
}
} else {
if (log.isTraceEnabled()) {
log.trace("Waiting for task to complete (blocking) at [{}]", endpoint.getEndpointUri());
}
// no timeout then wait until its done
try {
latch.await();
} catch (InterruptedException e) {
// ignore
}
}
} else {
// no wait, eg its a InOnly then just publish to the ringbuffer and return
// handover the completion so its the copy which performs that, as we do not wait
final Exchange copy = prepareCopy(exchange, true);
doPublish(copy);
}
// we use OnCompletion on the Exchange to callback and wait for the Exchange to be done
// so we should just signal the callback we are done synchronously
callback.done(true);
return true;
}
private void doPublish(Exchange exchange) {
log.trace("Publishing Exchange to disruptor ringbuffer: {}", exchange);
try {
if (blockWhenFull) {
endpoint.publish(exchange);
} else {
endpoint.tryPublish(exchange);
}
} catch (DisruptorNotStartedException e) {
throw new IllegalStateException("Disruptor was not started", e);
} catch (InsufficientCapacityException e) {
throw new IllegalStateException("Disruptors ringbuffer was full", e);
}
}
private Exchange prepareCopy(final Exchange exchange, final boolean handover) {
// use a new copy of the exchange to route async
final Exchange copy = ExchangeHelper.createCorrelatedCopy(exchange, handover);
// set a new from endpoint to be the disruptor
copy.setFromEndpoint(endpoint);
return copy;
}
}