Package org.springframework.batch.item.database

Class JpaCursorItemReader<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.database.JpaCursorItemReader<T>

Type Parameters:

T - type of items to read

All Implemented Interfaces:

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

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

ItemStreamReader implementation based on JPA Query.getResultStream(). It executes the JPQL query when initialized and iterates over the result set as AbstractItemCountingItemStreamItemReader.read() method is called, returning an object corresponding to the current row. The query can be set directly using setQueryString(String), or using a query provider via setQueryProvider(JpaQueryProvider).

The implementation is not thread-safe.

Since:

4.3

Author:

Mahmoud Ben Hassine

Constructor Summary

Constructors

Constructor	Description
JpaCursorItemReader()	Create a new JpaCursorItemReader.

Method Summary

Modifier and Type	Method	Description
void	afterPropertiesSet()
protected void	doClose()	Close the resources opened in AbstractItemCountingItemStreamItemReader.doOpen().
protected void	doOpen()	Open resources necessary to start reading input.
protected T	doRead()	Read next item from input.
void	setEntityManagerFactory(jakarta.persistence.EntityManagerFactory entityManagerFactory)	Set the JPA entity manager factory.
void	setParameterValues(Map<String,Object> parameterValues)	Set the parameter values to be used for the query execution.
void	setQueryProvider(JpaQueryProvider queryProvider)	Set the JPA query provider.
void	setQueryString(String queryString)	Set the JPQL query string.
void	update(ExecutionContext executionContext)	Return empty ExecutionContext.

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

close, getCurrentItemCount, isSaveState, jumpToItem, open, read, setCurrentItemCount, setMaxItemCount, setSaveState

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

JpaCursorItemReader

public JpaCursorItemReader()

Create a new JpaCursorItemReader.

Method Details

setEntityManagerFactory

public void setEntityManagerFactory(jakarta.persistence.EntityManagerFactory entityManagerFactory)

Set the JPA entity manager factory.

Parameters:

entityManagerFactory - JPA entity manager factory

setQueryProvider

public void setQueryProvider(JpaQueryProvider queryProvider)

Set the JPA query provider.

Parameters:

queryProvider - JPA query provider

setQueryString

public void setQueryString(String queryString)

Set the JPQL query string.

Parameters:

queryString - JPQL query string

setParameterValues

public void setParameterValues(Map<String,Object> parameterValues)

Set the parameter values to be used for the query execution.

Parameters:

parameterValues - the values keyed by parameter names used in the query string.

afterPropertiesSet

public void afterPropertiesSet()
                        throws Exception

Specified by:

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

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 - Allows subclasses to throw checked exceptions for interpretation by the framework

doRead

protected T doRead()

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

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 AbstractItemCountingItemStreamItemReader<T>

Parameters:

executionContext - to be updated

Throws:

ItemStreamException

See Also:

• ItemStream.update(ExecutionContext)

doClose

protected void doClose()

Description copied from class: AbstractItemCountingItemStreamItemReader

Close the resources opened in AbstractItemCountingItemStreamItemReader.doOpen().

Specified by:

doClose in class AbstractItemCountingItemStreamItemReader<T>