org.apache.camel.processor.MulticastProcessor Maven / Gradle / Ivy
/*
* 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.processor;
import java.io.Closeable;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.Executor;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.atomic.AtomicReference;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;
import org.apache.camel.AggregationStrategy;
import org.apache.camel.AsyncCallback;
import org.apache.camel.AsyncProcessor;
import org.apache.camel.CamelContext;
import org.apache.camel.CamelContextAware;
import org.apache.camel.CamelExchangeException;
import org.apache.camel.Endpoint;
import org.apache.camel.ErrorHandlerFactory;
import org.apache.camel.Exchange;
import org.apache.camel.Navigate;
import org.apache.camel.Processor;
import org.apache.camel.Producer;
import org.apache.camel.RuntimeCamelException;
import org.apache.camel.StreamCache;
import org.apache.camel.Traceable;
import org.apache.camel.spi.IdAware;
import org.apache.camel.spi.RouteContext;
import org.apache.camel.spi.UnitOfWork;
import org.apache.camel.support.AsyncProcessorConverterHelper;
import org.apache.camel.support.AsyncProcessorSupport;
import org.apache.camel.support.EventHelper;
import org.apache.camel.support.ExchangeHelper;
import org.apache.camel.support.service.ServiceHelper;
import org.apache.camel.util.CastUtils;
import org.apache.camel.util.IOHelper;
import org.apache.camel.util.KeyValueHolder;
import org.apache.camel.util.StopWatch;
import org.apache.camel.util.concurrent.AsyncCompletionService;
import static org.apache.camel.util.ObjectHelper.notNull;
/**
* Implements the Multicast pattern to send a message exchange to a number of
* endpoints, each endpoint receiving a copy of the message exchange.
*
* @see Pipeline
*/
public class MulticastProcessor extends AsyncProcessorSupport implements Navigate, Traceable, IdAware {
/**
* Class that represent each step in the multicast route to do
*/
static final class DefaultProcessorExchangePair implements ProcessorExchangePair {
private final int index;
private final Processor processor;
private final Processor prepared;
private final Exchange exchange;
private DefaultProcessorExchangePair(int index, Processor processor, Processor prepared, Exchange exchange) {
this.index = index;
this.processor = processor;
this.prepared = prepared;
this.exchange = exchange;
}
@Override
public int getIndex() {
return index;
}
@Override
public Exchange getExchange() {
return exchange;
}
@Override
public Producer getProducer() {
if (processor instanceof Producer) {
return (Producer) processor;
}
return null;
}
@Override
public Processor getProcessor() {
return prepared;
}
@Override
public void begin() {
// noop
}
@Override
public void done() {
// noop
}
}
/**
* Class that represents prepared fine grained error handlers when processing multicasted/splitted exchanges
*
* See the createProcessorExchangePair and createErrorHandler methods.
*/
static final class PreparedErrorHandler extends KeyValueHolder {
PreparedErrorHandler(RouteContext key, Processor value) {
super(key, value);
}
}
protected final Processor onPrepare;
private final CamelContext camelContext;
private String id;
private Collection processors;
private final AggregationStrategy aggregationStrategy;
private final boolean parallelProcessing;
private final boolean streaming;
private final boolean parallelAggregate;
private final boolean stopOnAggregateException;
private final boolean stopOnException;
private final ExecutorService executorService;
private final boolean shutdownExecutorService;
private ExecutorService aggregateExecutorService;
private final long timeout;
private final ConcurrentMap errorHandlers = new ConcurrentHashMap<>();
private final boolean shareUnitOfWork;
public MulticastProcessor(CamelContext camelContext, Collection processors) {
this(camelContext, processors, null);
}
public MulticastProcessor(CamelContext camelContext, Collection processors, AggregationStrategy aggregationStrategy) {
this(camelContext, processors, aggregationStrategy, false, null, false, false, false, 0, null, false, false);
}
public MulticastProcessor(CamelContext camelContext, Collection processors, AggregationStrategy aggregationStrategy, boolean parallelProcessing,
ExecutorService executorService, boolean shutdownExecutorService, boolean streaming, boolean stopOnException, long timeout, Processor onPrepare,
boolean shareUnitOfWork, boolean parallelAggregate) {
this(camelContext, processors, aggregationStrategy, parallelProcessing, executorService, shutdownExecutorService, streaming, stopOnException, timeout, onPrepare,
shareUnitOfWork, parallelAggregate, false);
}
public MulticastProcessor(CamelContext camelContext, Collection processors, AggregationStrategy aggregationStrategy,
boolean parallelProcessing, ExecutorService executorService, boolean shutdownExecutorService, boolean streaming,
boolean stopOnException, long timeout, Processor onPrepare, boolean shareUnitOfWork,
boolean parallelAggregate, boolean stopOnAggregateException) {
notNull(camelContext, "camelContext");
this.camelContext = camelContext;
this.processors = processors;
this.aggregationStrategy = aggregationStrategy;
this.executorService = executorService;
this.shutdownExecutorService = shutdownExecutorService;
this.streaming = streaming;
this.stopOnException = stopOnException;
// must enable parallel if executor service is provided
this.parallelProcessing = parallelProcessing || executorService != null;
this.timeout = timeout;
this.onPrepare = onPrepare;
this.shareUnitOfWork = shareUnitOfWork;
this.parallelAggregate = parallelAggregate;
this.stopOnAggregateException = stopOnAggregateException;
}
@Override
public String toString() {
return "Multicast[" + getProcessors() + "]";
}
@Override
public String getId() {
return id;
}
@Override
public void setId(String id) {
this.id = id;
}
@Override
public String getTraceLabel() {
return "multicast";
}
public CamelContext getCamelContext() {
return camelContext;
}
@Override
public boolean process(Exchange exchange, AsyncCallback callback) {
Iterable pairs;
try {
pairs = createProcessorExchangePairs(exchange);
} catch (Throwable e) {
exchange.setException(e);
// unexpected exception was thrown, maybe from iterator etc. so do not regard as exhausted
// and do the done work
doDone(exchange, null, null, callback, true, false);
return true;
}
MulticastState state = new MulticastState(exchange, pairs, callback);
if (isParallelProcessing()) {
executorService.submit(() -> exchange.getContext().getReactiveExecutor().schedule(state));
} else {
if (exchange.isTransacted()) {
exchange.getContext().getReactiveExecutor().scheduleSync(state);
} else {
exchange.getContext().getReactiveExecutor().scheduleMain(state);
}
}
// the remainder of the multicast will be completed async
// so we break out now, then the callback will be invoked which then
// continue routing from where we left here
return false;
}
protected void schedule(Runnable runnable) {
if (isParallelProcessing()) {
executorService.submit(() -> camelContext.getReactiveExecutor().schedule(runnable));
} else {
camelContext.getReactiveExecutor().schedule(runnable, "Multicast next step");
}
}
protected class MulticastState implements Runnable {
final Exchange original;
final Iterable pairs;
final AsyncCallback callback;
final Iterator iterator;
final ReentrantLock lock;
final AsyncCompletionService completion;
final AtomicReference result;
final AtomicInteger nbExchangeSent = new AtomicInteger();
final AtomicInteger nbAggregated = new AtomicInteger();
final AtomicBoolean allSent = new AtomicBoolean();
final AtomicBoolean done = new AtomicBoolean();
MulticastState(Exchange original, Iterable pairs, AsyncCallback callback) {
this.original = original;
this.pairs = pairs;
this.callback = callback;
this.iterator = pairs.iterator();
this.lock = new ReentrantLock();
this.completion = new AsyncCompletionService<>(MulticastProcessor.this::schedule, !isStreaming(), lock);
this.result = new AtomicReference<>();
if (timeout > 0) {
schedule(aggregateExecutorService, this::timeout, timeout, TimeUnit.MILLISECONDS);
}
}
@Override
public String toString() {
return "MulticastTask[" + original.getExchangeId() + "," + MulticastProcessor.this + "]";
}
@Override
public void run() {
try {
if (done.get()) {
return;
}
// Check if the iterator is empty
// This can happen the very first time we check the existence
// of an item before queuing the run.
// or some iterators may return true for hasNext() but then null in next()
if (!iterator.hasNext()) {
doDone(result.get(), true);
return;
}
ProcessorExchangePair pair = iterator.next();
boolean hasNext = iterator.hasNext();
// some iterators may return true for hasNext() but then null in next()
if (pair == null && !hasNext) {
doDone(result.get(), true);
return;
}
Exchange exchange = pair.getExchange();
int index = nbExchangeSent.getAndIncrement();
updateNewExchange(exchange, index, pairs, hasNext);
// Schedule the processing of the next pair
if (hasNext) {
if (isParallelProcessing()) {
schedule(this);
}
} else {
allSent.set(true);
}
completion.submit(exchangeResult -> {
// compute time taken if sending to another endpoint
StopWatch watch = beforeSend(pair);
AsyncProcessor async = AsyncProcessorConverterHelper.convert(pair.getProcessor());
async.process(exchange, doneSync -> {
afterSend(pair, watch);
// Decide whether to continue with the multicast or not; similar logic to the Pipeline
// remember to test for stop on exception and aggregate before copying back results
boolean continueProcessing = PipelineHelper.continueProcessing(exchange, "Multicast processing failed for number " + index, log);
if (stopOnException && !continueProcessing) {
if (exchange.getException() != null) {
// wrap in exception to explain where it failed
exchange.setException(new CamelExchangeException("Multicast processing failed for number " + index, exchange, exchange.getException()));
} else {
// we want to stop on exception, and the exception was handled by the error handler
// this is similar to what the pipeline does, so we should do the same to not surprise end users
// so we should set the failed exchange as the result and be done
result.set(exchange);
}
// and do the done work
doDone(exchange, true);
return;
}
exchangeResult.accept(exchange);
// aggregate exchanges if any
aggregate();
// next step
if (hasNext && !isParallelProcessing()) {
schedule(this);
}
});
});
} catch (Exception e) {
original.setException(e);
doDone(null, false);
}
}
protected void aggregate() {
Lock lock = this.lock;
if (lock.tryLock()) {
try {
Exchange exchange;
while (!done.get() && (exchange = completion.poll()) != null) {
doAggregate(result, exchange, original);
if (nbAggregated.incrementAndGet() >= nbExchangeSent.get() && allSent.get()) {
doDone(result.get(), true);
}
}
} catch (Throwable e) {
original.setException(e);
// and do the done work
doDone(null, false);
} finally {
lock.unlock();
}
}
}
protected void timeout() {
Lock lock = this.lock;
if (lock.tryLock()) {
try {
while (nbAggregated.get() < nbExchangeSent.get()) {
Exchange exchange = completion.pollUnordered();
int index = exchange != null ? getExchangeIndex(exchange) : nbExchangeSent.get();
while (nbAggregated.get() < index) {
AggregationStrategy strategy = getAggregationStrategy(null);
strategy.timeout(result.get() != null ? result.get() : original,
nbAggregated.getAndIncrement(), nbExchangeSent.get(), timeout);
}
if (exchange != null) {
doAggregate(result, exchange, original);
nbAggregated.incrementAndGet();
}
}
doDone(result.get(), true);
} catch (Throwable e) {
original.setException(e);
// and do the done work
doDone(null, false);
} finally {
lock.unlock();
}
}
}
protected void doDone(Exchange exchange, boolean forceExhaust) {
if (done.compareAndSet(false, true)) {
MulticastProcessor.this.doDone(original, exchange, pairs, callback, false, forceExhaust);
}
}
}
protected void schedule(Executor executor, Runnable runnable, long delay, TimeUnit unit) {
if (executor instanceof ScheduledExecutorService) {
((ScheduledExecutorService) executor).schedule(runnable, delay, unit);
} else {
executor.execute(() -> {
try {
Thread.sleep(delay);
} catch (InterruptedException e) {
// ignore
}
runnable.run();
});
}
}
protected StopWatch beforeSend(ProcessorExchangePair pair) {
StopWatch watch;
final Exchange e = pair.getExchange();
final Producer p = pair.getProducer();
if (p != null) {
boolean sending = EventHelper.notifyExchangeSending(e.getContext(), e, p.getEndpoint());
if (sending) {
watch = new StopWatch();
} else {
watch = null;
}
} else {
watch = null;
}
// let the prepared process it, remember to begin the exchange pair
pair.begin();
// return the watch
return watch;
}
protected void afterSend(ProcessorExchangePair pair, StopWatch watch) {
// we are done with the exchange pair
pair.done();
// okay we are done, so notify the exchange was sent
final Producer producer = pair.getProducer();
if (producer != null && watch != null) {
long timeTaken = watch.taken();
final Exchange e = pair.getExchange();
Endpoint endpoint = producer.getEndpoint();
// emit event that the exchange was sent to the endpoint
EventHelper.notifyExchangeSent(e.getContext(), e, endpoint, timeTaken);
}
}
/**
* Common work which must be done when we are done multicasting.
*
* This logic applies for both running synchronous and asynchronous as there are multiple exist points
* when using the asynchronous routing engine. And therefore we want the logic in one method instead
* of being scattered.
*
* @param original the original exchange
* @param subExchange the current sub exchange, can be null for the synchronous part
* @param pairs the pairs with the exchanges to process
* @param callback the callback
* @param doneSync the doneSync parameter to call on callback
* @param forceExhaust whether or not error handling is exhausted
*/
protected void doDone(Exchange original, Exchange subExchange, final Iterable pairs,
AsyncCallback callback, boolean doneSync, boolean forceExhaust) {
// we are done so close the pairs iterator
if (pairs instanceof Closeable) {
IOHelper.close((Closeable) pairs, "pairs", log);
}
AggregationStrategy strategy = getAggregationStrategy(subExchange);
// invoke the on completion callback
if (strategy != null) {
strategy.onCompletion(subExchange);
}
// cleanup any per exchange aggregation strategy
removeAggregationStrategyFromExchange(original);
// we need to know if there was an exception, and if the stopOnException option was enabled
// also we would need to know if any error handler has attempted redelivery and exhausted
boolean stoppedOnException = false;
boolean exception = false;
boolean exhaust = forceExhaust || subExchange != null && (subExchange.getException() != null || ExchangeHelper.isRedeliveryExhausted(subExchange));
if (original.getException() != null || subExchange != null && subExchange.getException() != null) {
// there was an exception and we stopped
stoppedOnException = isStopOnException();
exception = true;
}
// must copy results at this point
if (subExchange != null) {
if (stoppedOnException) {
// if we stopped due an exception then only propagate the exception
original.setException(subExchange.getException());
} else {
// copy the current result to original so it will contain this result of this eip
ExchangeHelper.copyResults(original, subExchange);
}
}
// .. and then if there was an exception we need to configure the redelivery exhaust
// for example the noErrorHandler will not cause redelivery exhaust so if this error
// handled has been in use, then the exhaust would be false (if not forced)
if (exception) {
// multicast uses error handling on its output processors and they have tried to redeliver
// so we shall signal back to the other error handlers that we are exhausted and they should not
// also try to redeliver as we would then do that twice
original.setProperty(Exchange.REDELIVERY_EXHAUSTED, exhaust);
}
camelContext.getReactiveExecutor().callback(callback);
}
/**
* Aggregate the {@link Exchange} with the current result.
* This method is synchronized and is called directly when parallelAggregate is disabled (by default).
*
* @param result the current result
* @param exchange the exchange to be added to the result
* @param inputExchange the input exchange that was sent as input to this EIP
*/
protected void doAggregate(AtomicReference result, Exchange exchange, Exchange inputExchange) {
if (parallelAggregate) {
doAggregateInternal(getAggregationStrategy(exchange), result, exchange, inputExchange);
} else {
doAggregateSync(getAggregationStrategy(exchange), result, exchange, inputExchange);
}
}
/**
* Aggregate the {@link Exchange} with the current result.
* This method is synchronized and is called directly when parallelAggregate is disabled (by default).
*
* @param strategy the aggregation strategy to use
* @param result the current result
* @param exchange the exchange to be added to the result
* @param inputExchange the input exchange that was sent as input to this EIP
*/
private synchronized void doAggregateSync(AggregationStrategy strategy, AtomicReference result, Exchange exchange, Exchange inputExchange) {
doAggregateInternal(strategy, result, exchange, inputExchange);
}
/**
* Aggregate the {@link Exchange} with the current result.
* This method is unsynchronized and is called directly when parallelAggregate is enabled.
* In all other cases, this method is called from the doAggregate which is a synchronized method
*
* @param strategy the aggregation strategy to use
* @param result the current result
* @param exchange the exchange to be added to the result
* @param inputExchange the input exchange that was sent as input to this EIP
*/
private void doAggregateInternal(AggregationStrategy strategy, AtomicReference result, Exchange exchange, Exchange inputExchange) {
if (strategy != null) {
// prepare the exchanges for aggregation
Exchange oldExchange = result.get();
ExchangeHelper.prepareAggregation(oldExchange, exchange);
result.set(strategy.aggregate(oldExchange, exchange, inputExchange));
}
}
protected void updateNewExchange(Exchange exchange, int index, Iterable allPairs, boolean hasNext) {
exchange.setProperty(Exchange.MULTICAST_INDEX, index);
if (hasNext) {
exchange.setProperty(Exchange.MULTICAST_COMPLETE, Boolean.FALSE);
} else {
exchange.setProperty(Exchange.MULTICAST_COMPLETE, Boolean.TRUE);
}
}
protected Integer getExchangeIndex(Exchange exchange) {
return exchange.getProperty(Exchange.MULTICAST_INDEX, Integer.class);
}
protected Iterable createProcessorExchangePairs(Exchange exchange) throws Exception {
List result = new ArrayList<>(processors.size());
StreamCache streamCache = null;
if (isParallelProcessing() && exchange.getIn().getBody() instanceof StreamCache) {
// in parallel processing case, the stream must be copied, therefore get the stream
streamCache = (StreamCache) exchange.getIn().getBody();
}
int index = 0;
for (Processor processor : processors) {
// copy exchange, and do not share the unit of work
Exchange copy = ExchangeHelper.createCorrelatedCopy(exchange, false);
if (streamCache != null) {
if (index > 0) {
// copy it otherwise parallel processing is not possible,
// because streams can only be read once
StreamCache copiedStreamCache = streamCache.copy(copy);
if (copiedStreamCache != null) {
copy.getIn().setBody(copiedStreamCache);
}
}
}
// If the multi-cast processor has an aggregation strategy
// then the StreamCache created by the child routes must not be
// closed by the unit of work of the child route, but by the unit of
// work of the parent route or grand parent route or grand grand parent route ...(in case of nesting).
// Set therefore the unit of work of the parent route as stream cache unit of work,
// if it is not already set.
if (copy.getProperty(Exchange.STREAM_CACHE_UNIT_OF_WORK) == null) {
copy.setProperty(Exchange.STREAM_CACHE_UNIT_OF_WORK, exchange.getUnitOfWork());
}
// if we share unit of work, we need to prepare the child exchange
if (isShareUnitOfWork()) {
prepareSharedUnitOfWork(copy, exchange);
}
// and add the pair
RouteContext routeContext = exchange.getUnitOfWork() != null ? exchange.getUnitOfWork().getRouteContext() : null;
result.add(createProcessorExchangePair(index++, processor, copy, routeContext));
}
if (exchange.getException() != null) {
// force any exceptions occurred during creation of exchange paris to be thrown
// before returning the answer;
throw exchange.getException();
}
return result;
}
/**
* Creates the {@link ProcessorExchangePair} which holds the processor and exchange to be send out.
*
* You must use this method to create the instances of {@link ProcessorExchangePair} as they
* need to be specially prepared before use.
*
* @param index the index
* @param processor the processor
* @param exchange the exchange
* @param routeContext the route context
* @return prepared for use
*/
protected ProcessorExchangePair createProcessorExchangePair(int index, Processor processor, Exchange exchange,
RouteContext routeContext) {
Processor prepared = processor;
// set property which endpoint we send to
setToEndpoint(exchange, prepared);
// rework error handling to support fine grained error handling
prepared = createErrorHandler(routeContext, exchange, prepared);
// invoke on prepare on the exchange if specified
if (onPrepare != null) {
try {
onPrepare.process(exchange);
} catch (Exception e) {
exchange.setException(e);
}
}
return new DefaultProcessorExchangePair(index, processor, prepared, exchange);
}
protected Processor createErrorHandler(RouteContext routeContext, Exchange exchange, Processor processor) {
Processor answer;
boolean tryBlock = exchange.getProperty(Exchange.TRY_ROUTE_BLOCK, false, boolean.class);
// do not wrap in error handler if we are inside a try block
if (!tryBlock && routeContext != null) {
// wrap the producer in error handler so we have fine grained error handling on
// the output side instead of the input side
// this is needed to support redelivery on that output alone and not doing redelivery
// for the entire multicast block again which will start from scratch again
// create key for cache
final PreparedErrorHandler key = new PreparedErrorHandler(routeContext, processor);
// lookup cached first to reuse and preserve memory
answer = errorHandlers.get(key);
if (answer != null) {
log.trace("Using existing error handler for: {}", processor);
return answer;
}
log.trace("Creating error handler for: {}", processor);
ErrorHandlerFactory builder = routeContext.getErrorHandlerFactory();
// create error handler (create error handler directly to keep it light weight,
// instead of using ProcessorDefinition.wrapInErrorHandler)
try {
processor = builder.createErrorHandler(routeContext, processor);
// and wrap in unit of work processor so the copy exchange also can run under UoW
answer = createUnitOfWorkProcessor(routeContext, processor, exchange);
boolean child = exchange.getProperty(Exchange.PARENT_UNIT_OF_WORK, UnitOfWork.class) != null;
// must start the error handler
ServiceHelper.startService(answer);
// here we don't cache the child unit of work
if (!child) {
// add to cache
errorHandlers.putIfAbsent(key, answer);
}
} catch (Exception e) {
throw RuntimeCamelException.wrapRuntimeCamelException(e);
}
} else {
// and wrap in unit of work processor so the copy exchange also can run under UoW
answer = createUnitOfWorkProcessor(routeContext, processor, exchange);
}
return answer;
}
/**
* Strategy to create the unit of work to be used for the sub route
*
* @param routeContext the route context
* @param processor the processor
* @param exchange the exchange
* @return the unit of work processor
*/
protected Processor createUnitOfWorkProcessor(RouteContext routeContext, Processor processor, Exchange exchange) {
CamelInternalProcessor internal = new CamelInternalProcessor(processor);
// and wrap it in a unit of work so the UoW is on the top, so the entire route will be in the same UoW
UnitOfWork parent = exchange.getProperty(Exchange.PARENT_UNIT_OF_WORK, UnitOfWork.class);
if (parent != null) {
internal.addAdvice(new CamelInternalProcessor.ChildUnitOfWorkProcessorAdvice(routeContext, parent));
} else {
internal.addAdvice(new CamelInternalProcessor.UnitOfWorkProcessorAdvice(routeContext));
}
return internal;
}
/**
* Prepares the exchange for participating in a shared unit of work
*
* This ensures a child exchange can access its parent {@link UnitOfWork} when it participate
* in a shared unit of work.
*
* @param childExchange the child exchange
* @param parentExchange the parent exchange
*/
protected void prepareSharedUnitOfWork(Exchange childExchange, Exchange parentExchange) {
childExchange.setProperty(Exchange.PARENT_UNIT_OF_WORK, parentExchange.getUnitOfWork());
}
@Override
protected void doStart() throws Exception {
if (isParallelProcessing() && executorService == null) {
throw new IllegalArgumentException("ParallelProcessing is enabled but ExecutorService has not been set");
}
if (aggregateExecutorService == null) {
// use unbounded thread pool so we ensure the aggregate on-the-fly task always will have assigned a thread
// and run the tasks when the task is submitted. If not then the aggregate task may not be able to run
// and signal completion during processing, which would lead to what would appear as a dead-lock or a slow processing
String name = getClass().getSimpleName() + "-AggregateTask";
aggregateExecutorService = createAggregateExecutorService(name);
}
if (aggregationStrategy instanceof CamelContextAware) {
((CamelContextAware) aggregationStrategy).setCamelContext(camelContext);
}
ServiceHelper.startService(aggregationStrategy, processors);
}
/**
* Strategy to create the thread pool for the aggregator background task which waits for and aggregates
* completed tasks when running in parallel mode.
*
* @param name the suggested name for the background thread
* @return the thread pool
*/
protected synchronized ExecutorService createAggregateExecutorService(String name) {
// use a cached thread pool so we each on-the-fly task has a dedicated thread to process completions as they come in
return camelContext.getExecutorServiceManager().newScheduledThreadPool(this, name, 0);
}
@Override
protected void doStop() throws Exception {
ServiceHelper.stopService(processors, errorHandlers, aggregationStrategy);
}
@Override
protected void doShutdown() throws Exception {
ServiceHelper.stopAndShutdownServices(processors, errorHandlers, aggregationStrategy);
// only clear error handlers when shutting down
errorHandlers.clear();
if (shutdownExecutorService && executorService != null) {
getCamelContext().getExecutorServiceManager().shutdownNow(executorService);
}
if (aggregateExecutorService != null) {
getCamelContext().getExecutorServiceManager().shutdownNow(aggregateExecutorService);
}
}
protected static void setToEndpoint(Exchange exchange, Processor processor) {
if (processor instanceof Producer) {
Producer producer = (Producer) processor;
exchange.setProperty(Exchange.TO_ENDPOINT, producer.getEndpoint().getEndpointUri());
}
}
protected AggregationStrategy getAggregationStrategy(Exchange exchange) {
AggregationStrategy answer = null;
// prefer to use per Exchange aggregation strategy over a global strategy
if (exchange != null) {
Map property = exchange.getProperty(Exchange.AGGREGATION_STRATEGY, Map.class);
Map map = CastUtils.cast(property);
if (map != null) {
answer = map.get(this);
}
}
if (answer == null) {
// fallback to global strategy
answer = getAggregationStrategy();
}
return answer;
}
/**
* Sets the given {@link AggregationStrategy} on the {@link Exchange}.
*
* @param exchange the exchange
* @param aggregationStrategy the strategy
*/
protected void setAggregationStrategyOnExchange(Exchange exchange, AggregationStrategy aggregationStrategy) {
Map property = exchange.getProperty(Exchange.AGGREGATION_STRATEGY, Map.class);
Map map = CastUtils.cast(property);
if (map == null) {
map = new ConcurrentHashMap<>();
} else {
// it is not safe to use the map directly as the exchange doesn't have the deep copy of it's properties
// we just create a new copy if we need to change the map
map = new ConcurrentHashMap<>(map);
}
// store the strategy using this processor as the key
// (so we can store multiple strategies on the same exchange)
map.put(this, aggregationStrategy);
exchange.setProperty(Exchange.AGGREGATION_STRATEGY, map);
}
/**
* Removes the associated {@link AggregationStrategy} from the {@link Exchange}
* which must be done after use.
*
* @param exchange the current exchange
*/
protected void removeAggregationStrategyFromExchange(Exchange exchange) {
Map property = exchange.getProperty(Exchange.AGGREGATION_STRATEGY, Map.class);
Map map = CastUtils.cast(property);
if (map == null) {
return;
}
// remove the strategy using this processor as the key
map.remove(this);
}
/**
* Is the multicast processor working in streaming mode?
*
* In streaming mode:
*
* - we use {@link Iterable} to ensure we can send messages as soon as the data becomes available
* - for parallel processing, we start aggregating responses as they get send back to the processor;
* this means the {@link AggregationStrategy} has to take care of handling out-of-order arrival of exchanges
*
*/
public boolean isStreaming() {
return streaming;
}
/**
* Should the multicast processor stop processing further exchanges in case of an exception occurred?
*/
public boolean isStopOnException() {
return stopOnException;
}
/**
* Returns the producers to multicast to
*/
public Collection getProcessors() {
return processors;
}
/**
* An optional timeout in millis when using parallel processing
*/
public long getTimeout() {
return timeout;
}
/**
* Use {@link #getAggregationStrategy(org.apache.camel.Exchange)} instead.
*/
public AggregationStrategy getAggregationStrategy() {
return aggregationStrategy;
}
public boolean isParallelProcessing() {
return parallelProcessing;
}
public boolean isParallelAggregate() {
return parallelAggregate;
}
public boolean isStopOnAggregateException() {
return stopOnAggregateException;
}
public boolean isShareUnitOfWork() {
return shareUnitOfWork;
}
@Override
public List next() {
if (!hasNext()) {
return null;
}
return new ArrayList<>(processors);
}
@Override
public boolean hasNext() {
return processors != null && !processors.isEmpty();
}
}
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