Package org.springframework.batch.item.file

Class MultiResourceItemWriter<T>

java.lang.Object

org.springframework.batch.item.ItemStreamSupport

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

org.springframework.batch.item.file.MultiResourceItemWriter<T>

Type Parameters:

T - item type

All Implemented Interfaces:

ItemStream, ItemStreamWriter<T>, ItemWriter<T>

public class MultiResourceItemWriter<T>
extends AbstractItemStreamItemWriter<T>

Wraps a ResourceAwareItemWriterItemStream and creates a new output resource when the count of items written in current resource exceeds setItemCountLimitPerResource(int). Suffix creation can be customized with setResourceSuffixCreator(ResourceSuffixCreator).

Note that new resources are created only at chunk boundaries i.e. the number of items written into one resource is between the limit set by

This writer will create an output file only when there are items to write, which means there would be no empty file created if no items are passed (for example when all items are filtered or skipped during the processing phase).

Author:

Robert Kasanicky, Mahmoud Ben Hassine

Constructor Summary

Constructors

Constructor	Description
MultiResourceItemWriter()

Method Summary

Modifier and Type	Method	Description
void	close()	No-op.
void	open(ExecutionContext executionContext)	No-op.
void	setDelegate(ResourceAwareItemWriterItemStream<? super T> delegate)	Delegate used for actual writing of the output.
void	setItemCountLimitPerResource(int itemCountLimitPerResource)	After this limit is exceeded the next chunk will be written into newly created resource.
void	setResource(org.springframework.core.io.Resource resource)	Prototype for output resources.
void	setResourceSuffixCreator(ResourceSuffixCreator suffixCreator)	Allows customization of the suffix of the created resources based on the index.
void	setSaveState(boolean saveState)	Indicates that the state of the reader will be saved after each commit.
void	update(ExecutionContext executionContext)	Return empty ExecutionContext.
void	write(Chunk<? extends T> items)	Process the supplied data element.

Methods inherited from class org.springframework.batch.item.ItemStreamSupport

getExecutionContextKey, getName, setExecutionContextName, setName

Methods inherited from class java.lang.Object

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

Constructor Details

MultiResourceItemWriter

public MultiResourceItemWriter()

Method Details

write

public void write(Chunk<? extends T> items)
           throws Exception

Description copied from interface: ItemWriter

Process the supplied data element. Will not be called with any null items in normal operation.

Parameters:

items - of items to be written. Must not be null.

Throws:

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

setResourceSuffixCreator

public void setResourceSuffixCreator(ResourceSuffixCreator suffixCreator)

Allows customization of the suffix of the created resources based on the index.

Parameters:

suffixCreator - ResourceSuffixCreator to be used by the writer.

setItemCountLimitPerResource

public void setItemCountLimitPerResource(int itemCountLimitPerResource)

After this limit is exceeded the next chunk will be written into newly created resource.

Parameters:

itemCountLimitPerResource - int item threshold used to determine when a new resource should be created.

setDelegate

public void setDelegate(ResourceAwareItemWriterItemStream<? super T> delegate)

Delegate used for actual writing of the output.

Parameters:

delegate - ResourceAwareItemWriterItemStream that will be used to write the output.

setResource

public void setResource(org.springframework.core.io.Resource resource)

Prototype for output resources. Actual output files will be created in the same directory and use the same name as this prototype with appended suffix (according to setResourceSuffixCreator(ResourceSuffixCreator).

Parameters:

resource - The prototype resource.

setSaveState

public void setSaveState(boolean saveState)

Indicates that the state of the reader will be saved after each commit.

Parameters:

saveState - true the state is saved.

close

public void close()
           throws ItemStreamException

Description copied from class: ItemStreamSupport

No-op.

Specified by:

close in interface ItemStream

Overrides:

close in class ItemStreamSupport

Throws:

ItemStreamException

See Also:

• ItemStream.close()

open

public void open(ExecutionContext executionContext)
          throws ItemStreamException

Description copied from class: ItemStreamSupport

No-op.

Specified by:

open in interface ItemStream

Overrides:

open in class ItemStreamSupport

Parameters:

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

Throws:

ItemStreamException

See Also:

• ItemStream.open(ExecutionContext)

update

public void update(ExecutionContext executionContext)
            throws ItemStreamException

Description copied from class: ItemStreamSupport

Return empty ExecutionContext.

Specified by:

update in interface ItemStream

Overrides:

update in class ItemStreamSupport

Parameters:

executionContext - to be updated

Throws:

ItemStreamException

See Also:

• ItemStream.update(ExecutionContext)