/**
* 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.seda;
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.TimeUnit;
import org.apache.camel.Consumer;
import org.apache.camel.Endpoint;
import org.apache.camel.Exchange;
import org.apache.camel.Processor;
import org.apache.camel.ShutdownRunningTask;
import org.apache.camel.impl.LoggingExceptionHandler;
import org.apache.camel.impl.ServiceSupport;
import org.apache.camel.processor.MulticastProcessor;
import org.apache.camel.spi.ExceptionHandler;
import org.apache.camel.spi.ShutdownAware;
import org.apache.camel.util.ServiceHelper;
import org.apache.camel.util.concurrent.ExecutorServiceHelper;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
/**
* A Consumer for the SEDA component.
*
* @version $Revision: 893983 $
*/
public class SedaConsumer extends ServiceSupport implements Consumer, Runnable, ShutdownAware {
private static final transient Log LOG = LogFactory.getLog(SedaConsumer.class);
private SedaEndpoint endpoint;
private Processor processor;
private ExecutorService executor;
private Processor multicast;
private ExceptionHandler exceptionHandler;
public SedaConsumer(SedaEndpoint endpoint, Processor processor) {
this.endpoint = endpoint;
this.processor = processor;
}
@Override
public String toString() {
return "SedaConsumer[" + endpoint.getEndpointUri() + "]";
}
public Endpoint getEndpoint() {
return endpoint;
}
public ExceptionHandler getExceptionHandler() {
if (exceptionHandler == null) {
exceptionHandler = new LoggingExceptionHandler(getClass());
}
return exceptionHandler;
}
public void setExceptionHandler(ExceptionHandler exceptionHandler) {
this.exceptionHandler = exceptionHandler;
}
public Processor getProcessor() {
return processor;
}
public boolean deferShutdown(ShutdownRunningTask shutdownRunningTask) {
// deny stopping on shutdown as we want seda consumers to run in case some other queues
// depend on this consumer to run, so it can complete its exchanges
return true;
}
public int getPendingExchangesSize() {
// number of pending messages on the queue
return endpoint.getQueue().size();
}
public void run() {
BlockingQueue<Exchange> queue = endpoint.getQueue();
while (queue != null && isRunAllowed()) {
final Exchange exchange;
try {
exchange = queue.poll(1000, TimeUnit.MILLISECONDS);
} catch (InterruptedException e) {
if (LOG.isDebugEnabled()) {
LOG.debug("Sleep interrupted, are we stopping? " + (isStopping() || isStopped()));
}
continue;
}
if (exchange != null) {
if (isRunAllowed()) {
try {
sendToConsumers(exchange);
// log exception if an exception occurred and was not handled
if (exchange.getException() != null) {
getExceptionHandler().handleException("Error processing exchange", exchange, exchange.getException());
}
} catch (Exception e) {
getExceptionHandler().handleException("Error processing exchange", exchange, e);
}
} else {
if (LOG.isWarnEnabled()) {
LOG.warn("This consumer is stopped during polling an exchange, so putting it back on the seda queue: " + exchange);
}
try {
queue.put(exchange);
} catch (InterruptedException e) {
if (LOG.isDebugEnabled()) {
LOG.debug("Sleep interrupted, are we stopping? " + (isStopping() || isStopped()));
}
continue;
}
}
}
}
}
/**
* Send the given {@link Exchange} to the consumer(s).
* <p/>
* If multiple consumers then they will each receive a copy of the Exchange.
* A multicast processor will send the exchange in parallel to the multiple consumers.
* <p/>
* If there is only a single consumer then its dispatched directly to it using same thread.
*
* @param exchange the exchange
* @throws Exception can be thrown if processing of the exchange failed
*/
protected void sendToConsumers(Exchange exchange) throws Exception {
int size = endpoint.getConsumers().size();
// if there are multiple consumers then multicast to them
if (size > 1) {
if (LOG.isDebugEnabled()) {
LOG.debug("Multicasting to " + endpoint.getConsumers().size() + " consumers for Exchange: " + exchange);
}
// use a multicast processor to process it
Processor mp = getMulticastProcessor();
mp.process(exchange);
} else {
// use the regular processor
processor.process(exchange);
}
}
protected synchronized Processor getMulticastProcessor() {
if (multicast == null) {
int size = endpoint.getConsumers().size();
List<Processor> processors = new ArrayList<Processor>(size);
for (SedaConsumer consumer : endpoint.getConsumers()) {
processors.add(consumer.getProcessor());
}
ExecutorService multicastExecutor = ExecutorServiceHelper.newFixedThreadPool(size, endpoint.getEndpointUri() + "(multicast)", true);
multicast = new MulticastProcessor(processors, null, true, multicastExecutor, false, false);
}
return multicast;
}
protected void doStart() throws Exception {
int poolSize = endpoint.getConcurrentConsumers();
executor = ExecutorServiceHelper.newFixedThreadPool(poolSize, endpoint.getEndpointUri(), true);
for (int i = 0; i < poolSize; i++) {
executor.execute(this);
}
endpoint.onStarted(this);
}
protected void doStop() throws Exception {
endpoint.onStopped(this);
executor.shutdownNow();
executor = null;
if (multicast != null) {
ServiceHelper.stopServices(multicast);
}
}
}