/*
* Copyright (c) MuleSoft, Inc. All rights reserved. http://www.mulesoft.com
* The software in this package is published under the terms of the CPAL v1.0
* license, a copy of which has been included with this distribution in the
* LICENSE.txt file.
*/
package org.mule.transport;
import org.mule.api.MessagingException;
import org.mule.api.MuleEvent;
import org.mule.api.MuleException;
import org.mule.api.MuleMessage;
import org.mule.api.config.ThreadingProfile;
import org.mule.api.construct.FlowConstruct;
import org.mule.api.endpoint.InboundEndpoint;
import org.mule.api.exception.SystemExceptionHandler;
import org.mule.api.execution.ExecutionCallback;
import org.mule.api.execution.ExecutionTemplate;
import org.mule.api.lifecycle.CreateException;
import org.mule.api.transport.Connector;
import java.util.List;
import java.util.concurrent.CountDownLatch;
import javax.resource.spi.work.Work;
/**
* The TransactedPollingMessageReceiver is an abstract receiver that handles polling
* and transaction management. Derived implementations of these class must be thread
* safe as several threads can be started at once for an improved throughput.
*/
public abstract class TransactedPollingMessageReceiver extends AbstractPollingMessageReceiver
{
/**
* time to sleep when there are no messages in the queue to avoid busy waiting *
*/
private static final long NO_MESSAGES_SLEEP_TIME = Long.parseLong(System.getProperty("mule.vm.pollingSleepWaitTime", "50"));
/**
* determines whether messages will be received in a transaction template
*/
private boolean receiveMessagesInTransaction = true;
/**
* determines whether Multiple receivers are created to improve throughput
*/
private boolean useMultipleReceivers = true;
public TransactedPollingMessageReceiver(Connector connector,
FlowConstruct flowConstruct,
final InboundEndpoint endpoint) throws CreateException
{
super(connector, flowConstruct, endpoint);
this.setReceiveMessagesInTransaction(endpoint.getTransactionConfig().isTransacted());
}
/**
* @deprecated please use
* {@link #TransactedPollingMessageReceiver(Connector, FlowConstruct, InboundEndpoint)}
* instead
*/
@Deprecated
public TransactedPollingMessageReceiver(Connector connector,
FlowConstruct flowConstruct,
final InboundEndpoint endpoint,
long frequency) throws CreateException
{
this(connector, flowConstruct, endpoint);
this.setFrequency(frequency);
}
public boolean isReceiveMessagesInTransaction()
{
return receiveMessagesInTransaction;
}
public void setReceiveMessagesInTransaction(boolean useTx)
{
receiveMessagesInTransaction = useTx;
}
public boolean isUseMultipleTransactedReceivers()
{
return useMultipleReceivers;
}
public void setUseMultipleTransactedReceivers(boolean useMultiple)
{
useMultipleReceivers = useMultiple;
}
@Override
public void doStart() throws MuleException
{
// Connector property overrides any implied value
this.setUseMultipleTransactedReceivers(connector.isCreateMultipleTransactedReceivers());
ThreadingProfile tp = connector.getReceiverThreadingProfile();
int numReceiversToStart = 1;
if (this.isReceiveMessagesInTransaction() && this.isUseMultipleTransactedReceivers()
&& tp.isDoThreading())
{
numReceiversToStart = connector.getNumberOfConcurrentTransactedReceivers();
}
for (int i = 0; i < numReceiversToStart; i++)
{
super.doStart();
}
}
@Override
public void poll() throws Exception
{
try
{
ExecutionTemplate<MuleEvent> pt = createExecutionTemplate();
if (this.isReceiveMessagesInTransaction())
{
if (hasNoMessages())
{
if (NO_MESSAGES_SLEEP_TIME > 0)
{
Thread.sleep(NO_MESSAGES_SLEEP_TIME);
}
return;
}
// Receive messages and process them in a single transaction
// Do not enable threading here, but several workers
// may have been started
ExecutionCallback<MuleEvent> cb = new ExecutionCallback<MuleEvent>()
{
@Override
public MuleEvent process() throws Exception
{
// this is not ideal, but jdbc receiver returns a list of maps, not List<MuleMessage>
List messages = getMessages();
if (messages != null && messages.size() > 0)
{
for (Object message : messages)
{
processMessage(message);
}
}
return null; //To change body of implemented methods use File | Settings | File Templates.
}
};
pt.execute(cb);
}
else
{
// Receive messages and launch a worker for each message
List messages = getMessages();
if (messages != null && messages.size() > 0)
{
final CountDownLatch countdown = new CountDownLatch(messages.size());
for (Object message : messages)
{
try
{
this.getWorkManager().scheduleWork(
new MessageProcessorWorker(pt, countdown, endpoint.getMuleContext().getExceptionListener(), message));
}
catch (Exception e)
{
countdown.countDown();
throw e;
}
}
countdown.await();
}
}
}
catch (MessagingException e)
{
//Already handled by exception strategy
}
catch (Exception e)
{
getEndpoint().getMuleContext().handleException(e);
}
}
/**
* Return true if it can be determined that there are currently no messages to process
*/
protected boolean hasNoMessages()
{
return false;
}
protected class MessageProcessorWorker implements Work, ExecutionCallback<MuleEvent>
{
private final ExecutionTemplate<MuleEvent> pt;
private final Object message;
private final CountDownLatch latch;
private final SystemExceptionHandler exceptionHandler;
public MessageProcessorWorker(ExecutionTemplate<MuleEvent> pt, CountDownLatch latch, SystemExceptionHandler exceptionHandler, Object message)
{
this.pt = pt;
this.message = message;
this.latch = latch;
this.exceptionHandler = exceptionHandler;
}
@Override
public void release()
{
// nothing to do
}
@Override
public void run()
{
try
{
pt.execute(this);
}
catch (MessagingException e)
{
//already managed by TransactionTemplate
}
catch (Exception e)
{
exceptionHandler.handleException(e);
}
finally
{
latch.countDown();
}
}
@Override
public MuleEvent process() throws Exception
{
processMessage(message);
return null;
}
}
protected abstract List<MuleMessage> getMessages() throws Exception;
protected abstract void processMessage(Object message) throws Exception;
}