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, ItemStreamReader<T>, 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).

It is important to note that this is a paging item reader and exceptions that are thrown while reading the page itself (mapping results to objects, etc in the doPageRead()) will not be skippable since this reader has no way of knowing if an exception should be skipped and therefore will continue to read the same page until the skip limit is exceeded.

NOTE: The RepositoryItemReader only reads Java Objects i.e. non primitives.

Since:

2.2

Author:

Michael Minella, Antoine Kapps, Mahmoud Ben Hassine

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

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 java.util.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(java.util.List<?> arguments) Arguments to be passed to the data providing method.
void	setMethodName(java.lang.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(java.util.Map<java.lang.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, setSaveState, update

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

Field Detail

logger

protected org.apache.commons.logging.Log logger

Constructor Detail

RepositoryItemReader

public RepositoryItemReader()

Method Detail

setArguments

public void setArguments(java.util.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(java.util.Map<java.lang.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. Must be greater than 0.

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(java.lang.String methodName)

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

Parameters:

methodName - name of the method to invoke

afterPropertiesSet

public void afterPropertiesSet()
                        throws java.lang.Exception

Specified by:

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

Throws:

java.lang.Exception

doRead

@Nullable
protected T doRead()
                      throws java.lang.Exception

Description copied from class: AbstractItemCountingItemStreamItemReader

Read next item from input.

Specified by:

doRead in class AbstractItemCountingItemStreamItemReader<T>

Returns:

an item or null if the data source is exhausted

Throws:

java.lang.Exception - Allows subclasses to throw checked exceptions for interpretation by the framework

jumpToItem

protected void jumpToItem(int itemLastIndex)
                   throws java.lang.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>

Parameters:

itemLastIndex - index of item (0 based) to jump to.

Throws:

java.lang.Exception - Allows subclasses to throw checked exceptions for interpretation by the framework

doPageRead

protected java.util.List<T> doPageRead()
                                throws java.lang.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:

java.lang.Exception - Based on what the underlying method throws or related to the calling of the method

doOpen

protected void doOpen()
               throws java.lang.Exception

Description copied from class: AbstractItemCountingItemStreamItemReader

Open resources necessary to start reading input.

Specified by:

doOpen in class AbstractItemCountingItemStreamItemReader<T>

Throws:

java.lang.Exception - Allows subclasses to throw checked exceptions for interpretation by the framework

doClose

protected void doClose()
                throws java.lang.Exception

Description copied from class: AbstractItemCountingItemStreamItemReader

Close the resources opened in AbstractItemCountingItemStreamItemReader.doOpen().

Specified by:

doClose in class AbstractItemCountingItemStreamItemReader<T>

Throws:

java.lang.Exception - Allows subclasses to throw checked exceptions for interpretation by the framework