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

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

All Implemented Interfaces:

ItemReader<T>, ItemStream, InitializingBean

public class HibernateCursorItemReader<T>
extends AbstractItemCountingItemStreamItemReader<T>
implements ItemStream, InitializingBean

ItemReader for reading database records built on top of Hibernate. It executes the HQL query when initialized iterates over the result set as AbstractItemCountingItemStreamItemReader.read() method is called, returning an object corresponding to current row. The query can be set directly using setQueryString(String) or a named query can be used by setQueryName(String).

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 update(ExecutionContext) method without being flushed (no data modifications are expected).

The implementation is not thread-safe.

Author:

Robert Kasanicky, Dave Syer

Constructor Summary

HibernateCursorItemReader()

Method Summary

void	afterPropertiesSet()
protected void	doClose() Close the cursor and hibernate session.
protected void	doOpen() Open hibernate session and create a forward-only cursor for the setQueryString(String).
protected T	doRead() Read next item from input.
void	setFetchSize(int fetchSize) Gives the JDBC driver a hint as to the number of rows that should be fetched from the database when more rows are needed for this ResultSet object.
void	setQueryName(String queryName)
void	setQueryString(String queryString)
void	setSessionFactory(org.hibernate.SessionFactory sessionFactory)
void	setUseStatelessSession(boolean useStatelessSession) Can be set only in uninitialized state.
void	update(ExecutionContext executionContext) Clears the session if not stateful and delegates to super class.

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

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

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

Constructor Detail

HibernateCursorItemReader

public HibernateCursorItemReader()

Method Detail

setSessionFactory

public void setSessionFactory(org.hibernate.SessionFactory sessionFactory)

Parameters:

sessionFactory - hibernate session factory

afterPropertiesSet

public void afterPropertiesSet()
                        throws Exception

Specified by:

afterPropertiesSet in interface InitializingBean

Throws:

Exception

setQueryName

public void setQueryName(String queryName)

Parameters:

queryName - name of a hibernate named query

setQueryString

public void setQueryString(String queryString)

Parameters:

queryString - HQL query string

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

update

public void update(ExecutionContext executionContext)
            throws ItemStreamException

Clears the session if not stateful and delegates to super class.

Specified by:

update in interface ItemStream

Overrides:

update in class AbstractItemCountingItemStreamItemReader<T>

Parameters:

executionContext - to be updated

Throws:

ItemStreamException

setFetchSize

public void setFetchSize(int fetchSize)

Gives the JDBC driver a hint as to the number of rows that should be fetched from the database when more rows are needed for this ResultSet object. If the fetch size specified is zero, the JDBC driver ignores the value.

Parameters:

fetchSize - the number of rows to fetch, 0 by default

See Also:

Query.setFetchSize(int)

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

doOpen

protected void doOpen()
               throws Exception

Open hibernate session and create a forward-only cursor for the setQueryString(String).

Specified by:

doOpen in class AbstractItemCountingItemStreamItemReader<T>

Throws:

Exception

doClose

protected void doClose()
                throws Exception

Close the cursor and hibernate session.

Specified by:

doClose in class AbstractItemCountingItemStreamItemReader<T>

Throws:

Exception