/**
* This logic is only executed if we have to retry redelivery asynchronously, which have to be
* done from the callback.
*
* <p>And therefore the logic is a bit different than the synchronous <tt>processErrorHandler</tt>
* method which can use a loop based redelivery technique. However this means that these two
* methods in overall have to be in <b>sync</b> in terms of logic.
*/
protected void processAsyncErrorHandler(
final Exchange exchange, final AsyncCallback callback, final RedeliveryData data) {
// can we still run
if (!isRunAllowed()) {
if (exchange.getException() == null) {
exchange.setException(new RejectedExecutionException());
}
callback.done(data.sync);
return;
}
// did previous processing cause an exception?
boolean handle = shouldHandleException(exchange);
if (handle) {
handleException(exchange, data);
}
// compute if we are exhausted or not
boolean exhausted = isExhausted(exchange, data);
if (exhausted) {
Processor target = null;
boolean deliver = true;
// the unit of work may have an optional callback associated we need to leverage
SubUnitOfWorkCallback uowCallback = exchange.getUnitOfWork().getSubUnitOfWorkCallback();
if (uowCallback != null) {
// signal to the callback we are exhausted
uowCallback.onExhausted(exchange);
// do not deliver to the failure processor as its been handled by the callback instead
deliver = false;
}
if (deliver) {
// should deliver to failure processor (either from onException or the dead letter channel)
target = data.failureProcessor != null ? data.failureProcessor : data.deadLetterProcessor;
}
// we should always invoke the deliverToFailureProcessor as it prepares, logs and does a fair
// bit of work for exhausted exchanges (its only the target processor which may be null if
// handled by a savepoint)
deliverToFailureProcessor(target, exchange, data, callback);
// we are breaking out
return;
}
if (data.redeliveryCounter > 0) {
// let the RedeliverTask be the logic which tries to redeliver the Exchange which we can used
// a scheduler to
// have it being executed in the future, or immediately
// Note: the data.redeliverFromSync should be kept as is, in case it was enabled previously
// to ensure the callback will continue routing from where we left
AsyncRedeliveryTask task = new AsyncRedeliveryTask(exchange, callback, data);
// calculate the redelivery delay
data.redeliveryDelay =
data.currentRedeliveryPolicy.calculateRedeliveryDelay(
data.redeliveryDelay, data.redeliveryCounter);
if (data.redeliveryDelay > 0) {
// schedule the redelivery task
if (log.isTraceEnabled()) {
log.trace(
"Scheduling redelivery task to run in {} millis for exchangeId: {}",
data.redeliveryDelay,
exchange.getExchangeId());
}
executorService.schedule(task, data.redeliveryDelay, TimeUnit.MILLISECONDS);
} else {
// execute the task immediately
executorService.submit(task);
}
}
}
/** Process the exchange using redelivery error handling. */
protected boolean processErrorHandler(
final Exchange exchange, final AsyncCallback callback, final RedeliveryData data) {
// do a defensive copy of the original Exchange, which is needed for redelivery so we can ensure
// the
// original Exchange is being redelivered, and not a mutated Exchange
data.original = defensiveCopyExchangeIfNeeded(exchange);
// use looping to have redelivery attempts
while (true) {
// can we still run
if (!isRunAllowed()) {
if (exchange.getException() == null) {
exchange.setException(new RejectedExecutionException());
}
// we cannot process so invoke callback
callback.done(data.sync);
return data.sync;
}
// did previous processing cause an exception?
boolean handle = shouldHandleException(exchange);
if (handle) {
handleException(exchange, data);
}
// compute if we are exhausted or not
boolean exhausted = isExhausted(exchange, data);
if (exhausted) {
Processor target = null;
boolean deliver = true;
// the unit of work may have an optional callback associated we need to leverage
SubUnitOfWorkCallback uowCallback = exchange.getUnitOfWork().getSubUnitOfWorkCallback();
if (uowCallback != null) {
// signal to the callback we are exhausted
uowCallback.onExhausted(exchange);
// do not deliver to the failure processor as its been handled by the callback instead
deliver = false;
}
if (deliver) {
// should deliver to failure processor (either from onException or the dead letter
// channel)
target = data.failureProcessor != null ? data.failureProcessor : data.deadLetterProcessor;
}
// we should always invoke the deliverToFailureProcessor as it prepares, logs and does a
// fair
// bit of work for exhausted exchanges (its only the target processor which may be null if
// handled by a savepoint)
boolean sync = deliverToFailureProcessor(target, exchange, data, callback);
// we are breaking out
return sync;
}
if (data.redeliveryCounter > 0) {
// calculate delay
data.redeliveryDelay =
data.currentRedeliveryPolicy.calculateRedeliveryDelay(
data.redeliveryDelay, data.redeliveryCounter);
if (data.redeliveryDelay > 0) {
// okay there is a delay so create a scheduled task to have it executed in the future
if (data.currentRedeliveryPolicy.isAsyncDelayedRedelivery() && !exchange.isTransacted()) {
// let the RedeliverTask be the logic which tries to redeliver the Exchange which we can
// used a scheduler to
// have it being executed in the future, or immediately
// we are continuing asynchronously
// mark we are routing async from now and that this redelivery task came from a
// synchronous routing
data.sync = false;
data.redeliverFromSync = true;
AsyncRedeliveryTask task = new AsyncRedeliveryTask(exchange, callback, data);
// schedule the redelivery task
if (log.isTraceEnabled()) {
log.trace(
"Scheduling redelivery task to run in {} millis for exchangeId: {}",
data.redeliveryDelay,
exchange.getExchangeId());
}
executorService.schedule(task, data.redeliveryDelay, TimeUnit.MILLISECONDS);
return false;
} else {
// async delayed redelivery was disabled or we are transacted so we must be synchronous
// as the transaction manager requires to execute in the same thread context
try {
data.currentRedeliveryPolicy.sleep(data.redeliveryDelay);
} catch (InterruptedException e) {
// we was interrupted so break out
exchange.setException(e);
// mark the exchange to stop continue routing when interrupted
// as we do not want to continue routing (for example a task has been cancelled)
exchange.setProperty(Exchange.ROUTE_STOP, Boolean.TRUE);
callback.done(data.sync);
return data.sync;
}
}
}
// prepare for redelivery
prepareExchangeForRedelivery(exchange, data);
// letting onRedeliver be executed
deliverToOnRedeliveryProcessor(exchange, data);
// emmit event we are doing redelivery
EventHelper.notifyExchangeRedelivery(
exchange.getContext(), exchange, data.redeliveryCounter);
}
// process the exchange (also redelivery)
boolean sync =
AsyncProcessorHelper.process(
outputAsync,
exchange,
new AsyncCallback() {
public void done(boolean sync) {
// this callback should only handle the async case
if (sync) {
return;
}
// mark we are in async mode now
data.sync = false;
// if we are done then notify callback and exit
if (isDone(exchange)) {
callback.done(sync);
return;
}
// error occurred so loop back around which we do by invoking the
// processAsyncErrorHandler
// method which takes care of this in a asynchronous manner
processAsyncErrorHandler(exchange, callback, data);
}
});
if (!sync) {
// the remainder of the Exchange is being processed asynchronously so we should return
return false;
}
// we continue to route synchronously
// if we are done then notify callback and exit
boolean done = isDone(exchange);
if (done) {
callback.done(true);
return true;
}
// error occurred so loop back around.....
}
}