org.springframework.batch.item.support

Class SynchronizedItemStreamWriter<T>

java.lang.Object

org.springframework.batch.item.support.SynchronizedItemStreamWriter<T>

Type Parameters:

T - type of object being written

All Implemented Interfaces:

ItemStream, ItemStreamWriter<T>, ItemWriter<T>, org.springframework.beans.factory.InitializingBean

public class SynchronizedItemStreamWriter<T>
extends java.lang.Object
implements ItemStreamWriter<T>, org.springframework.beans.factory.InitializingBean

An ItemStreamWriter decorator with a synchronized write() method. This decorator is useful when using a non thread-safe item writer in a multi-threaded step. Typical delegate examples are the JsonFileItemWriter and StaxEventItemWriter.

It should be noted that synchronizing writes might introduce some performance degradation, so this decorator should be used wisely and only when necessary. For example, using a FlatFileItemWriter in a multi-threaded step does NOT require synchronizing writes, so using this decorator in such use case might be counter-productive.

Author:

Dimitrios Liapis, Mahmoud Ben Hassine

Constructor Summary

Constructors

Constructor and Description
SynchronizedItemStreamWriter()

Method Summary

Modifier and Type	Method and Description
void	afterPropertiesSet()
void	close() If any resources are needed for the stream to operate they need to be destroyed here.
void	open(ExecutionContext executionContext) Open the stream for the provided ExecutionContext.
void	setDelegate(ItemStreamWriter<T> delegate) Set the delegate ItemStreamWriter.
void	update(ExecutionContext executionContext) Indicates that the execution context provided during open is about to be saved.
void	write(java.util.List<? extends T> items) This method delegates to the write method of the delegate.

Methods inherited from class java.lang.Object

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

Constructor Detail

SynchronizedItemStreamWriter

public SynchronizedItemStreamWriter()

Method Detail

setDelegate

public void setDelegate(ItemStreamWriter<T> delegate)

Set the delegate ItemStreamWriter.

Parameters:

delegate - the delegate to set

write

public void write(java.util.List<? extends T> items)
           throws java.lang.Exception

This method delegates to the write method of the delegate.

Specified by:

write in interface ItemWriter<T>

Parameters:

items - items to be written

Throws:

java.lang.Exception - if there are errors. The framework will catch the exception and convert or rethrow it as appropriate.

open

public void open(ExecutionContext executionContext)
          throws ItemStreamException

Description copied from interface: ItemStream

Open the stream for the provided ExecutionContext.

Specified by:

open in interface ItemStream

Parameters:

executionContext - current step's ExecutionContext. Will be the executionContext from the last run of the step on a restart.

Throws:

ItemStreamException

update

public void update(ExecutionContext executionContext)
            throws ItemStreamException

Description copied from interface: ItemStream

Indicates that the execution context provided during open is about to be saved. If any state is remaining, but has not been put in the context, it should be added here.

Specified by:

update in interface ItemStream

Parameters:

executionContext - to be updated

Throws:

ItemStreamException

close

public void close()
           throws ItemStreamException

Description copied from interface: ItemStream

If any resources are needed for the stream to operate they need to be destroyed here. Once this method has been called all other methods (except open) may throw an exception.

Specified by:

close in interface ItemStream

Throws:

ItemStreamException

afterPropertiesSet

public void afterPropertiesSet()
                        throws java.lang.Exception

Specified by:

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

Throws:

java.lang.Exception