org.apache.camel.processor
Class RedeliveryErrorHandler

java.lang.Object
  org.apache.camel.support.ServiceSupport
      org.apache.camel.support.ChildServiceSupport
          org.apache.camel.processor.ErrorHandlerSupport
              org.apache.camel.processor.RedeliveryErrorHandler

All Implemented Interfaces:

AsyncProcessor, Processor, ErrorHandler, Service, ShutdownableService, StatefulService, SuspendableService

Direct Known Subclasses:

DeadLetterChannel, DefaultErrorHandler

public abstract class RedeliveryErrorHandler
extends ErrorHandlerSupport
implements AsyncProcessor

Base redeliverable error handler that also supports a final dead letter queue in case all redelivery attempts fail.

This implementation should contain all the error handling logic and the sub classes should only configure it according to what they support.

Version:

Nested Class Summary

protected class

RedeliveryErrorHandler.RedeliveryData Contains the current redelivery data

Field Summary

protected CamelContext	camelContext
protected Processor	deadLetter
protected String	deadLetterUri
protected ScheduledExecutorService	executorService
protected CamelLogger	logger
protected Processor	output
protected AsyncProcessor	outputAsync
protected boolean	redeliveryEnabled
protected RedeliveryPolicy	redeliveryPolicy
protected Processor	redeliveryProcessor
protected Predicate	retryWhilePolicy
protected boolean	useOriginalMessagePolicy

Fields inherited from class org.apache.camel.processor.ErrorHandlerSupport

exceptionPolicies, exceptionPolicy, log

Fields inherited from class org.apache.camel.support.ServiceSupport

shutdown, shuttingdown, started, starting, stopped, stopping, suspended, suspending

Constructor Summary

RedeliveryErrorHandler(CamelContext camelContext, Processor output, CamelLogger logger, Processor redeliveryProcessor, RedeliveryPolicy redeliveryPolicy, Processor deadLetter, String deadLetterUri, boolean useOriginalMessagePolicy, Predicate retryWhile, ScheduledExecutorService executorService)

Method Summary

protected Exchange	defensiveCopyExchangeIfNeeded(Exchange exchange) Performs a defensive copy of the exchange if needed
protected boolean	deliverToFailureProcessor(Processor processor, boolean isDeadLetterChannel, Exchange exchange, RedeliveryErrorHandler.RedeliveryData data, AsyncCallback callback) All redelivery attempts failed so move the exchange to the dead letter queue
protected void	deliverToOnRedeliveryProcessor(Exchange exchange, RedeliveryErrorHandler.RedeliveryData data) Gives an optional configure redelivery processor a chance to process before the Exchange will be redelivered.
protected long	determineRedeliveryDelay(Exchange exchange, RedeliveryPolicy redeliveryPolicy, long redeliveryDelay, int redeliveryCounter) Determines the redelivery delay time by first inspecting the Message header Exchange.REDELIVERY_DELAY and if not present, defaulting to RedeliveryPolicy.calculateRedeliveryDelay(long, int)
protected void	doShutdown() Implementations override this method to perform customized shutdown.
protected void	doStart() Implementations override this method to support customized start/stop.
protected void	doStop() Implementations override this method to support customized start/stop.
Processor	getDeadLetter() Returns the dead letter that message exchanges will be sent to if the redelivery attempts fail
String	getDeadLetterUri()
protected Predicate	getDefaultHandledPredicate()
CamelLogger	getLogger()
Processor	getOutput() Returns the output processor
RedeliveryPolicy	getRedeliveryPolicy()
protected void	handleException(Exchange exchange, RedeliveryErrorHandler.RedeliveryData data)
protected boolean	isCancelledOrInterrupted(Exchange exchange) Strategy to determine if the exchange was cancelled or interrupted
protected boolean	isDone(Exchange exchange) Strategy to determine if the exchange is done so we can continue
boolean	isRunAllowed() Helper methods so the service knows if it should keep running.
boolean	isUseOriginalMessagePolicy()
protected void	prepareExchangeAfterFailure(Exchange exchange, RedeliveryErrorHandler.RedeliveryData data, boolean shouldHandle, boolean shouldContinue)
protected void	prepareExchangeForContinue(Exchange exchange, RedeliveryErrorHandler.RedeliveryData data)
protected void	prepareExchangeForRedelivery(Exchange exchange, RedeliveryErrorHandler.RedeliveryData data)
void	process(Exchange exchange) Processes the message exchange
boolean	process(Exchange exchange, AsyncCallback callback) Processes the message exchange.
protected void	processAsyncErrorHandler(Exchange exchange, AsyncCallback callback, RedeliveryErrorHandler.RedeliveryData data) This logic is only executed if we have to retry redelivery asynchronously, which have to be done from the callback.
protected boolean	processErrorHandler(Exchange exchange, AsyncCallback callback, RedeliveryErrorHandler.RedeliveryData data) Process the exchange using redelivery error handling.
protected boolean	shouldHandleException(Exchange exchange) Strategy whether the exchange has an exception that we should try to handle.
boolean	supportTransacted() Whether this error handler supports transacted exchanges or not.

Methods inherited from class org.apache.camel.processor.ErrorHandlerSupport

addExceptionPolicy, createDefaultExceptionPolicyStrategy, getExceptionPolicy, isDeadLetterChannel, setExceptionPolicy

Methods inherited from class org.apache.camel.support.ChildServiceSupport

addChildService, removeChildService, shutdown, start, start, stop

Methods inherited from class org.apache.camel.support.ServiceSupport

doResume, doSuspend, getStatus, getVersion, isStarted, isStarting, isStopped, isStopping, isSuspended, isSuspending, resume, suspend

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

executorService

protected ScheduledExecutorService executorService

camelContext

protected final CamelContext camelContext

deadLetter

protected final Processor deadLetter

deadLetterUri

protected final String deadLetterUri

output

protected final Processor output

outputAsync

protected final AsyncProcessor outputAsync

redeliveryProcessor

protected final Processor redeliveryProcessor

redeliveryPolicy

protected final RedeliveryPolicy redeliveryPolicy

retryWhilePolicy

protected final Predicate retryWhilePolicy

logger

protected final CamelLogger logger

useOriginalMessagePolicy

protected final boolean useOriginalMessagePolicy

redeliveryEnabled

protected boolean redeliveryEnabled

Constructor Detail

RedeliveryErrorHandler

public RedeliveryErrorHandler(CamelContext camelContext,
                              Processor output,
                              CamelLogger logger,
                              Processor redeliveryProcessor,
                              RedeliveryPolicy redeliveryPolicy,
                              Processor deadLetter,
                              String deadLetterUri,
                              boolean useOriginalMessagePolicy,
                              Predicate retryWhile,
                              ScheduledExecutorService executorService)

Method Detail

supportTransacted

public boolean supportTransacted()

Description copied from class: ErrorHandlerSupport

Whether this error handler supports transacted exchanges or not.

Specified by:

supportTransacted in class ErrorHandlerSupport

isRunAllowed

public boolean isRunAllowed()

Description copied from interface: StatefulService

Helper methods so the service knows if it should keep running. Returns false if the service is being stopped or is stopped.

Specified by:

isRunAllowed in interface StatefulService

Overrides:

isRunAllowed in class ServiceSupport

Returns:

true if the service should continue to run.

process

public void process(Exchange exchange)
             throws Exception

Description copied from interface: Processor

Processes the message exchange

Specified by:

process in interface Processor

Parameters:

exchange - the message exchange

Throws:

Exception - if an internal processing error has occurred.

process

public boolean process(Exchange exchange,
                       AsyncCallback callback)

Description copied from interface: AsyncProcessor

Processes the message exchange. Similar to Processor.process(org.apache.camel.Exchange), but the caller supports having the exchange asynchronously processed.

If there was a failure processing then the caused Exception would be set on the Exchange.

Specified by:

process in interface AsyncProcessor

Parameters:

exchange - the message exchange

callback - the AsyncCallback will be invoked when the processing of the exchange is completed. If the exchange is completed synchronously, then the callback is also invoked synchronously. The callback should therefore be careful of starting recursive loop.

Returns:

(doneSync) true to continue execute synchronously, false to continue being executed asynchronously

See Also:

AsyncProcessorHelper.process(AsyncProcessor, Exchange, AsyncCallback)

processErrorHandler

protected boolean processErrorHandler(Exchange exchange,
                                      AsyncCallback callback,
                                      RedeliveryErrorHandler.RedeliveryData data)

Process the exchange using redelivery error handling.

determineRedeliveryDelay

protected long determineRedeliveryDelay(Exchange exchange,
                                        RedeliveryPolicy redeliveryPolicy,
                                        long redeliveryDelay,
                                        int redeliveryCounter)

Determines the redelivery delay time by first inspecting the Message header Exchange.REDELIVERY_DELAY and if not present, defaulting to RedeliveryPolicy.calculateRedeliveryDelay(long, int)

In order to prevent manipulation of the RedeliveryData state, the values of RedeliveryErrorHandler.RedeliveryData.redeliveryDelay and RedeliveryErrorHandler.RedeliveryData.redeliveryCounter are copied in.

Parameters:

exchange - The current exchange in question.

redeliveryPolicy - The RedeliveryPolicy to use in the calculation.

redeliveryDelay - The default redelivery delay from RedeliveryData

redeliveryCounter - The redeliveryCounter

Returns:

The time to wait before the next redelivery.

processAsyncErrorHandler

protected void processAsyncErrorHandler(Exchange exchange,
                                        AsyncCallback callback,
                                        RedeliveryErrorHandler.RedeliveryData data)

This logic is only executed if we have to retry redelivery asynchronously, which have to be done from the callback.

And therefore the logic is a bit different than the synchronous processErrorHandler method which can use a loop based redelivery technique. However this means that these two methods in overall have to be in sync in terms of logic.

defensiveCopyExchangeIfNeeded

protected Exchange defensiveCopyExchangeIfNeeded(Exchange exchange)

Performs a defensive copy of the exchange if needed

Parameters:

exchange - the exchange

Returns:

the defensive copy, or null if not needed (redelivery is not enabled).

shouldHandleException

protected boolean shouldHandleException(Exchange exchange)

Strategy whether the exchange has an exception that we should try to handle.

Standard implementations should just look for an exception.

isDone

protected boolean isDone(Exchange exchange)

Strategy to determine if the exchange is done so we can continue

isCancelledOrInterrupted

protected boolean isCancelledOrInterrupted(Exchange exchange)

Strategy to determine if the exchange was cancelled or interrupted

getOutput

public Processor getOutput()

Returns the output processor

Specified by:

getOutput in class ErrorHandlerSupport

getDeadLetter

public Processor getDeadLetter()

Returns the dead letter that message exchanges will be sent to if the redelivery attempts fail

getDeadLetterUri

public String getDeadLetterUri()

isUseOriginalMessagePolicy

public boolean isUseOriginalMessagePolicy()

getRedeliveryPolicy

public RedeliveryPolicy getRedeliveryPolicy()

getLogger

public CamelLogger getLogger()

getDefaultHandledPredicate

protected Predicate getDefaultHandledPredicate()

prepareExchangeForContinue

protected void prepareExchangeForContinue(Exchange exchange,
                                          RedeliveryErrorHandler.RedeliveryData data)

prepareExchangeForRedelivery

protected void prepareExchangeForRedelivery(Exchange exchange,
                                            RedeliveryErrorHandler.RedeliveryData data)

handleException

protected void handleException(Exchange exchange,
                               RedeliveryErrorHandler.RedeliveryData data)

deliverToOnRedeliveryProcessor

protected void deliverToOnRedeliveryProcessor(Exchange exchange,
                                              RedeliveryErrorHandler.RedeliveryData data)

Gives an optional configure redelivery processor a chance to process before the Exchange will be redelivered. This can be used to alter the Exchange.

deliverToFailureProcessor

protected boolean deliverToFailureProcessor(Processor processor,
                                            boolean isDeadLetterChannel,
                                            Exchange exchange,
                                            RedeliveryErrorHandler.RedeliveryData data,
                                            AsyncCallback callback)

All redelivery attempts failed so move the exchange to the dead letter queue

prepareExchangeAfterFailure

protected void prepareExchangeAfterFailure(Exchange exchange,
                                           RedeliveryErrorHandler.RedeliveryData data,
                                           boolean shouldHandle,
                                           boolean shouldContinue)

doStart

protected void doStart()
                throws Exception

Description copied from class: ServiceSupport

Implementations override this method to support customized start/stop.

Important: See ServiceSupport.doStop() for more details.

Specified by:

doStart in class ServiceSupport

Throws:

Exception

See Also:

ServiceSupport.doStop()

doStop

protected void doStop()
               throws Exception

Description copied from class: ServiceSupport

Implementations override this method to support customized start/stop.

Important: Camel will invoke this ServiceSupport.doStop() method when the service is being stopped. This method will also be invoked if the service is still in uninitialized state (eg has not been started). The method is always called to allow the service to do custom logic when the service is being stopped, such as when CamelContext is shutting down.

Specified by:

doStop in class ServiceSupport

Throws:

Exception

See Also:

ServiceSupport.doStart()

doShutdown

protected void doShutdown()
                   throws Exception

Description copied from class: ServiceSupport

Implementations override this method to perform customized shutdown.

Overrides:

doShutdown in class ServiceSupport

Throws:

Exception