org.springframework.batch.integration.async

Class AsyncItemProcessor<I,O>

java.lang.Object

org.springframework.batch.integration.async.AsyncItemProcessor<I,O>

Type Parameters:

I - the input object type

O - the output object type (will be wrapped in a Future)

All Implemented Interfaces:

ItemProcessor<I,java.util.concurrent.Future<O>>, org.springframework.beans.factory.InitializingBean

public class AsyncItemProcessor<I,O>
extends java.lang.Object
implements ItemProcessor<I,java.util.concurrent.Future<O>>, org.springframework.beans.factory.InitializingBean

An ItemProcessor that delegates to a nested processor and in the background. To allow for background processing the return value from the processor is a Future which needs to be unpacked before the item can be used by a client. Because the Future is typically unwrapped in the ItemWriter, there are lifecycle and stats limitations (since the framework doesn't know what the result of the processor is). While not an exhaustive list, things like StepExecution.filterCount will not reflect the number of filtered items and ItemProcessListener.onProcessError(Object, Exception) will not be called.

Author:

Dave Syer

See Also:

AsyncItemWriter

Constructor Summary

Constructors

Constructor and Description
AsyncItemProcessor()

Method Summary

Modifier and Type	Method and Description
void	afterPropertiesSet() Check mandatory properties (the setDelegate(ItemProcessor)).
java.util.concurrent.Future<O>	process(I item) Transform the input by delegating to the provided item processor.
void	setDelegate(ItemProcessor<I,O> delegate) The ItemProcessor to use to delegate processing to in a background thread.
void	setTaskExecutor(org.springframework.core.task.TaskExecutor taskExecutor) The TaskExecutor to use to allow the item processing to proceed in the background.

Methods inherited from class java.lang.Object

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

Constructor Detail

AsyncItemProcessor

public AsyncItemProcessor()

Method Detail

afterPropertiesSet

public void afterPropertiesSet()
                        throws java.lang.Exception

Check mandatory properties (the setDelegate(ItemProcessor)).

Specified by:

afterPropertiesSet in interface org.springframework.beans.factory.InitializingBean

Throws:

java.lang.Exception

See Also:

InitializingBean.afterPropertiesSet()

setDelegate

public void setDelegate(ItemProcessor<I,O> delegate)

The ItemProcessor to use to delegate processing to in a background thread.

Parameters:

delegate - the ItemProcessor to use as a delegate

setTaskExecutor

public void setTaskExecutor(org.springframework.core.task.TaskExecutor taskExecutor)

The TaskExecutor to use to allow the item processing to proceed in the background. Defaults to a SyncTaskExecutor so no threads are created unless this is overridden.

Parameters:

taskExecutor - a TaskExecutor

process

@Nullable
public java.util.concurrent.Future<O> process(I item)
                                                 throws java.lang.Exception

Transform the input by delegating to the provided item processor. The return value is wrapped in a Future so that clients can unpack it later.

Specified by:

process in interface ItemProcessor<I,java.util.concurrent.Future<O>>

Parameters:

item - to be processed

Returns:

potentially modified or new item for continued processing, null if processing of the provided item should not continue.

Throws:

java.lang.Exception - thrown if exception occurs during processing.

See Also:

ItemProcessor.process(Object)