org.springframework.batch.item.data

Class RepositoryItemReader<T>

java.lang.Object

org.springframework.batch.item.ItemStreamSupport

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

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

org.springframework.batch.item.data.RepositoryItemReader<T>

All Implemented Interfaces:

ItemReader<T>, ItemStream, org.springframework.beans.factory.InitializingBean

public class RepositoryItemReader<T>
extends AbstractItemCountingItemStreamItemReader<T>
implements org.springframework.beans.factory.InitializingBean

A ItemReader that reads records utilizing a PagingAndSortingRepository.

Performance of the reader is dependent on the repository implementation, however setting a reasonably large page size and matching that to the commit interval should yield better performance.

The reader must be configured with a PagingAndSortingRepository, a Sort, and a pageSize greater than 0.

This implementation is thread safe between calls to AbstractItemCountingItemStreamItemReader.open(ExecutionContext), but remember to use saveState=false if used in a multi-threaded client (no restart available).

Since:

2.2

Author:

Michael Minella

Field Summary

Fields

Modifier and Type	Field and Description
protected org.apache.commons.logging.Log	logger

Constructor Summary

Constructors

Constructor and Description
RepositoryItemReader()

Method Summary

Methods

Modifier and Type	Method and Description
void	afterPropertiesSet()
protected void	doClose() Close the resources opened in AbstractItemCountingItemStreamItemReader.doOpen().
protected void	doOpen() Open resources necessary to start reading input.
protected List<T>	doPageRead() Performs the actual reading of a page via the repository.
protected T	doRead() Read next item from input.
protected void	jumpToItem(int itemLastIndex) Move to the given item index.
void	setArguments(List arguments) Arguments to be passed to the data providing method.
void	setMethodName(String methodName) Specifies what method on the repository to call.
void	setPageSize(int pageSize)
void	setRepository(org.springframework.data.repository.PagingAndSortingRepository repository) The PagingAndSortingRepository implementation used to read input from.
void	setSort(Map<String,org.springframework.data.domain.Sort.Direction> sorts) Provides ordering of the results so that order is maintained between paged queries

Methods inherited from class org.springframework.batch.item.support.AbstractItemCountingItemStreamItemReader

close, getCurrentItemCount, isSaveState, open, read, setCurrentItemCount, setMaxItemCount, setName, setSaveState, update

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

getExecutionContextKey, setExecutionContextName

Methods inherited from class java.lang.Object

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

Field Detail

logger

protected org.apache.commons.logging.Log logger

Constructor Detail

RepositoryItemReader

public RepositoryItemReader()

Method Detail

setArguments

public void setArguments(List arguments)

Arguments to be passed to the data providing method.

Parameters:

arguments - list of method arguments to be passed to the repository

setSort

public void setSort(Map<String,org.springframework.data.domain.Sort.Direction> sorts)

Provides ordering of the results so that order is maintained between paged queries

Parameters:

sorts - the fields to sort by and the directions

setPageSize

public void setPageSize(int pageSize)

Parameters:

pageSize - The number of items to retrieve per page.

setRepository

public void setRepository(org.springframework.data.repository.PagingAndSortingRepository repository)

The PagingAndSortingRepository implementation used to read input from.

Parameters:

repository - underlying repository for input to be read from.

setMethodName

public void setMethodName(String methodName)

Specifies what method on the repository to call. This method must take Pageable as the last argument.

Parameters:

methodName -

afterPropertiesSet

public void afterPropertiesSet()
                        throws Exception

Specified by:

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

Throws:

Exception

doRead

protected T doRead()
            throws Exception

Description copied from class: AbstractItemCountingItemStreamItemReader

Read next item from input.

Specified by:

doRead in class AbstractItemCountingItemStreamItemReader<T>

Returns:

item

Throws:

Exception

jumpToItem

protected void jumpToItem(int itemLastIndex)
                   throws Exception

Description copied from class: AbstractItemCountingItemStreamItemReader

Move to the given item index. Subclasses should override this method if there is a more efficient way of moving to given index than re-reading the input using AbstractItemCountingItemStreamItemReader.doRead().

Overrides:

jumpToItem in class AbstractItemCountingItemStreamItemReader<T>

Throws:

Exception

doPageRead

protected List<T> doPageRead()
                      throws Exception

Performs the actual reading of a page via the repository. Available for overriding as needed.

Returns:

the list of items that make up the page

Throws:

Exception

doOpen

protected void doOpen()
               throws Exception

Description copied from class: AbstractItemCountingItemStreamItemReader

Open resources necessary to start reading input.

Specified by:

doOpen in class AbstractItemCountingItemStreamItemReader<T>

Throws:

Exception

doClose

protected void doClose()
                throws Exception

Description copied from class: AbstractItemCountingItemStreamItemReader

Close the resources opened in AbstractItemCountingItemStreamItemReader.doOpen().

Specified by:

doClose in class AbstractItemCountingItemStreamItemReader<T>

Throws:

Exception