org.springframework.batch.item.database
Class HibernatePagingItemReader<T>

java.lang.Object
  org.springframework.batch.item.support.AbstractItemCountingItemStreamItemReader<T>
      org.springframework.batch.item.database.AbstractPagingItemReader<T>
          org.springframework.batch.item.database.HibernatePagingItemReader<T>

All Implemented Interfaces:

ItemReader<T>, ItemStream, ItemStreamReader<T>, InitializingBean

public class HibernatePagingItemReader<T>
extends AbstractPagingItemReader<T>
implements ItemStream, InitializingBean

ItemReader for reading database records built on top of Hibernate and reading only up to a fixed number of items at a time. It executes an HQL query when initialized is paged as the AbstractItemCountingItemStreamItemReader.read() method is called. The query can be set directly using setQueryString(String), a named query can be used by setQueryName(String), or a query provider strategy can be supplied via setQueryProvider(HibernateQueryProvider).

The reader can be configured to use either StatelessSession sufficient for simple mappings without the need to cascade to associated objects or standard hibernate Session for more advanced mappings or when caching is desired. When stateful session is used it will be cleared in the AbstractItemCountingItemStreamItemReader.update(ExecutionContext) method without being flushed (no data modifications are expected).

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

Since:

2.1

Author:

Dave Syer

Field Summary

Fields inherited from class org.springframework.batch.item.database.AbstractPagingItemReader

logger, results

Constructor Summary

HibernatePagingItemReader()

Method Summary

void	afterPropertiesSet() Check mandatory properties.
protected void	doClose() Close the resources opened in AbstractItemCountingItemStreamItemReader.doOpen().
protected void	doJumpToPage(int itemIndex)
protected void	doOpen() Open resources necessary to start reading input.
protected void	doReadPage()
void	setFetchSize(int fetchSize) Fetch size used internally by Hibernate to limit amount of data fetched from database per round trip.
void	setParameterValues(Map<String,Object> parameterValues) The parameter values to apply to a query (map of name:value).
void	setQueryName(String queryName) A query name for an externalized query.
void	setQueryProvider(HibernateQueryProvider queryProvider) A query provider.
void	setQueryString(String queryString) A query string in HQL.
void	setSessionFactory(org.hibernate.SessionFactory sessionFactory) The Hibernate SessionFactory to use the create a session.
void	setUseStatelessSession(boolean useStatelessSession) Can be set only in uninitialized state.

Methods inherited from class org.springframework.batch.item.database.AbstractPagingItemReader

doRead, getPage, getPageSize, jumpToItem, setPageSize

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

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

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.springframework.batch.item.ItemStream

close, open, update

Constructor Detail

HibernatePagingItemReader

public HibernatePagingItemReader()

Method Detail

setParameterValues

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

The parameter values to apply to a query (map of name:value).

Parameters:

parameterValues - the parameter values to set

setQueryName

public void setQueryName(String queryName)

A query name for an externalized query. Either this or the { query string or the { query provider should be set.

Parameters:

queryName - name of a hibernate named query

setFetchSize

public void setFetchSize(int fetchSize)

Fetch size used internally by Hibernate to limit amount of data fetched from database per round trip.

Parameters:

fetchSize - the fetch size to pass down to Hibernate

setQueryProvider

public void setQueryProvider(HibernateQueryProvider queryProvider)

A query provider. Either this or the {query string or the {query name should be set.

Parameters:

queryProvider - Hibernate query provider

setQueryString

public void setQueryString(String queryString)

A query string in HQL. Either this or the { query provider or the { query name should be set.

Parameters:

queryString - HQL query string

setSessionFactory

public void setSessionFactory(org.hibernate.SessionFactory sessionFactory)

The Hibernate SessionFactory to use the create a session.

Parameters:

sessionFactory - the SessionFactory to set

setUseStatelessSession

public void setUseStatelessSession(boolean useStatelessSession)

Can be set only in uninitialized state.

Parameters:

useStatelessSession - true to use StatelessSession false to use standard hibernate Session

afterPropertiesSet

public void afterPropertiesSet()
                        throws Exception

Description copied from class: AbstractPagingItemReader

Check mandatory properties.

Specified by:

afterPropertiesSet in interface InitializingBean

Overrides:

afterPropertiesSet in class AbstractPagingItemReader<T>

Throws:

Exception

See Also:

InitializingBean.afterPropertiesSet()

doOpen

protected void doOpen()
               throws Exception

Description copied from class: AbstractItemCountingItemStreamItemReader

Open resources necessary to start reading input.

Overrides:

doOpen in class AbstractPagingItemReader<T>

Throws:

Exception

doReadPage

protected void doReadPage()

Specified by:

doReadPage in class AbstractPagingItemReader<T>

doJumpToPage

protected void doJumpToPage(int itemIndex)

Specified by:

doJumpToPage in class AbstractPagingItemReader<T>

doClose

protected void doClose()
                throws Exception

Description copied from class: AbstractItemCountingItemStreamItemReader

Close the resources opened in AbstractItemCountingItemStreamItemReader.doOpen().

Overrides:

doClose in class AbstractPagingItemReader<T>

Throws:

Exception