org.springframework.integration.handler
Class DelayHandler

java.lang.Object
  org.springframework.integration.handler.DelayHandler

All Implemented Interfaces:

org.springframework.beans.factory.BeanFactoryAware, org.springframework.beans.factory.DisposableBean, org.springframework.core.Ordered, MessageHandler

public class DelayHandler
extends java.lang.Object
implements MessageHandler, org.springframework.core.Ordered, org.springframework.beans.factory.BeanFactoryAware, org.springframework.beans.factory.DisposableBean

A MessageHandler that is capable of delaying the continuation of a Message flow based on the presence of a delay header on an inbound Message or a default delay value configured on this handler. Note that the continuation of the flow is delegated to a TaskScheduler, and therefore, the calling thread does not block. The advantage of this approach is that many delays can be managed concurrently, even very long delays, without producing a buildup of blocked Threads.

One thing to keep in mind, however, is that any active transactional context will not propagate from the original sender to the eventual recipient. This is a side-effect of passing the Message to the output channel after the delay with a different Thread in control.

When this handler's 'delayHeaderName' property is configured, that value, if present on a Message, will take precedence over the handler's 'defaultDelay' value. The actual header value may be a long, a String that can be parsed as a long, or a Date. If it is a long, it will be interpreted as the length of time to delay in milliseconds counting from the current time (e.g. a value of 5000 indicates that the Message can be released as soon as five seconds from the current time). If the value is a Date, it will be delayed at least until that Date occurs (i.e. the delay in that case is equivalent to headerDate.getTime() - new Date().getTime()).

Since:

1.0.3

Author:

Mark Fisher

Field Summary

Fields inherited from interface org.springframework.core.Ordered

HIGHEST_PRECEDENCE, LOWEST_PRECEDENCE

Constructor Summary

DelayHandler(long defaultDelay)
Create a DelayHandler with the given default delay.

DelayHandler(long defaultDelay, java.util.concurrent.ScheduledExecutorService scheduledExecutorService)
Create a DelayHandler with the given default delay.

Method Summary

void	destroy()
int	getOrder()
void	handleMessage(Message<?> message) Handles the message if possible.
void	setBeanFactory(org.springframework.beans.factory.BeanFactory beanFactory)
void	setDefaultDelay(long defaultDelay) Set the default delay in milliseconds.
void	setDelayHeaderName(java.lang.String delayHeaderName) Specify the name of the header that should be checked for a delay period (in milliseconds) or a Date to delay until.
void	setOrder(int order)
void	setOutputChannel(MessageChannel outputChannel) Set the output channel for this handler.
void	setSendTimeout(long sendTimeout) Set the timeout for sending reply Messages.
void	setWaitForTasksToCompleteOnShutdown(boolean waitForJobsToCompleteOnShutdown) Set whether to wait for scheduled tasks to complete on shutdown.

Methods inherited from class java.lang.Object

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

Constructor Detail

DelayHandler

public DelayHandler(long defaultDelay)

Create a DelayHandler with the given default delay. The sending of Messages after the delay will be handled by a scheduled thread pool with a size of 1.

DelayHandler

public DelayHandler(long defaultDelay,
                    java.util.concurrent.ScheduledExecutorService scheduledExecutorService)

Create a DelayHandler with the given default delay. The sending of Messages after the delay will be handled by the provided ScheduledExecutorService.

Method Detail

setDefaultDelay

public void setDefaultDelay(long defaultDelay)

Set the default delay in milliseconds. If no 'delayHeaderName' property has been provided, the default delay will be applied to all Messages. If a delay should only be applied to Messages with a header, then set this value to 0.

setDelayHeaderName

public void setDelayHeaderName(java.lang.String delayHeaderName)

Specify the name of the header that should be checked for a delay period (in milliseconds) or a Date to delay until. If this property is set, any such header value will take precedence over this handler's default delay.

setOutputChannel

public void setOutputChannel(MessageChannel outputChannel)

Set the output channel for this handler. If none is provided, each inbound Message must include a reply channel header.

setSendTimeout

public void setSendTimeout(long sendTimeout)

Set the timeout for sending reply Messages.

setWaitForTasksToCompleteOnShutdown

public void setWaitForTasksToCompleteOnShutdown(boolean waitForJobsToCompleteOnShutdown)

Set whether to wait for scheduled tasks to complete on shutdown.

Default is "false". Switch this to "true" if you prefer fully completed tasks at the expense of a longer shutdown phase.

See Also:

ExecutorService.shutdown(), ExecutorService.shutdownNow()

setOrder

public void setOrder(int order)

getOrder

public int getOrder()

Specified by:

getOrder in interface org.springframework.core.Ordered

setBeanFactory

public void setBeanFactory(org.springframework.beans.factory.BeanFactory beanFactory)
                    throws org.springframework.beans.BeansException

Specified by:

setBeanFactory in interface org.springframework.beans.factory.BeanFactoryAware

Throws:

org.springframework.beans.BeansException

handleMessage

public final void handleMessage(Message<?> message)

Description copied from interface: MessageHandler

Handles the message if possible. If the handler cannot deal with the message this will result in a MessageRejectedException e.g. in case of a Selective Consumer. When a consumer tries to handle a message, but fails to do so, a MessageHandlingException is thrown. In the last case it is recommended to treat the message as tainted and go into an error scenario.

When the handling results in a message being sent failure to send that message will result in a MessageDeliveryException.

Specified by:

handleMessage in interface MessageHandler

Parameters:

message - the message to be handled

destroy

public void destroy()

Specified by:

destroy in interface org.springframework.beans.factory.DisposableBean