org.springframework.orm.hibernate3.support
Class OpenSessionInViewInterceptor

java.lang.Object
  org.springframework.orm.hibernate3.HibernateAccessor
      org.springframework.orm.hibernate3.support.OpenSessionInViewInterceptor

All Implemented Interfaces:

Aware, BeanFactoryAware, InitializingBean, WebRequestInterceptor

public class OpenSessionInViewInterceptor
extends HibernateAccessor
implements WebRequestInterceptor

Spring web request interceptor that binds a Hibernate Session to the thread for the entire processing of the request.

This class is a concrete expression of the "Open Session in View" pattern, which is a pattern that allows for the lazy loading of associations in web views despite the original transactions already being completed.

This interceptor makes Hibernate Sessions available via the current thread, which will be autodetected by transaction managers. It is suitable for service layer transactions via HibernateTransactionManager or JtaTransactionManager as well as for non-transactional execution (if configured appropriately).

NOTE: This interceptor will by default not flush the Hibernate Session, with the flush mode being set to FlushMode.NEVER. It assumes that it will be used in combination with service layer transactions that handle the flushing: the active transaction manager will temporarily change the flush mode to FlushMode.AUTO during a read-write transaction, with the flush mode reset to FlushMode.NEVER at the end of each transaction. If you intend to use this interceptor without transactions, consider changing the default flush mode (through the "flushMode" property).

In contrast to OpenSessionInViewFilter, this interceptor is configured in a Spring application context and can thus take advantage of bean wiring. It inherits common Hibernate configuration properties from HibernateAccessor, to be configured in a bean definition.

WARNING: Applying this interceptor to existing logic can cause issues that have not appeared before, through the use of a single Hibernate Session for the processing of an entire request. In particular, the reassociation of persistent objects with a Hibernate Session has to occur at the very beginning of request processing, to avoid clashes with already loaded instances of the same objects.

Alternatively, turn this interceptor into deferred close mode, by specifying "singleSession"="false": It will not use a single session per request then, but rather let each data access operation or transaction use its own session (as would be the case without Open Session in View). Each of those sessions will be registered for deferred close though, which will actually be processed at request completion.

A single session per request allows for the most efficient first-level caching, but can cause side effects, for example on saveOrUpdate or when continuing after a rolled-back transaction. The deferred close strategy is as safe as no Open Session in View in that respect, while still allowing for lazy loading in views (but not providing a first-level cache for the entire request).

Since:

1.2

Author:

Juergen Hoeller

See Also:

setSingleSession(boolean), HibernateAccessor.setFlushMode(int), OpenSessionInViewFilter, HibernateInterceptor, HibernateTransactionManager, SessionFactoryUtils.getSession(org.hibernate.SessionFactory, boolean), TransactionSynchronizationManager

Field Summary

static String

PARTICIPATE_SUFFIX Suffix that gets appended to the SessionFactory toString() representation for the "participate in existing session handling" request attribute.

Fields inherited from class org.springframework.orm.hibernate3.HibernateAccessor

FLUSH_ALWAYS, FLUSH_AUTO, FLUSH_COMMIT, FLUSH_EAGER, FLUSH_NEVER, logger

Constructor Summary

OpenSessionInViewInterceptor()
Create a new OpenSessionInViewInterceptor, turning the default flushMode to FLUSH_NEVER.

Method Summary

void	afterCompletion(WebRequest request, Exception ex) Unbind the Hibernate Session from the thread and close it (in single session mode), or process deferred close for all sessions that have been opened during the current request (in deferred close mode).
protected String	getParticipateAttributeName() Return the name of the request attribute that identifies that a request is already intercepted.
protected boolean	isSingleSession() Return whether to use a single session for each request.
void	postHandle(WebRequest request, ModelMap model) Flush the Hibernate Session before view rendering, if necessary.
void	preHandle(WebRequest request) Open a new Hibernate Session according to the settings of this HibernateAccessor and bind it to the thread via the TransactionSynchronizationManager.
void	setSingleSession(boolean singleSession) Set whether to use a single session for each request.

Methods inherited from class org.springframework.orm.hibernate3.HibernateAccessor

afterPropertiesSet, applyFlushMode, convertHibernateAccessException, convertJdbcAccessException, convertJdbcAccessException, disableFilters, enableFilters, flushIfNecessary, getDefaultJdbcExceptionTranslator, getEntityInterceptor, getFilterNames, getFlushMode, getJdbcExceptionTranslator, getSessionFactory, setBeanFactory, setEntityInterceptor, setEntityInterceptorBeanName, setFilterName, setFilterNames, setFlushMode, setFlushModeName, setJdbcExceptionTranslator, setSessionFactory

Methods inherited from class java.lang.Object

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

Field Detail

PARTICIPATE_SUFFIX

public static final String PARTICIPATE_SUFFIX

Suffix that gets appended to the SessionFactory toString() representation for the "participate in existing session handling" request attribute.

See Also:

getParticipateAttributeName(), Constant Field Values

Constructor Detail

OpenSessionInViewInterceptor

public OpenSessionInViewInterceptor()

Create a new OpenSessionInViewInterceptor, turning the default flushMode to FLUSH_NEVER.

See Also:

HibernateAccessor.setFlushMode(int)

Method Detail

setSingleSession

public void setSingleSession(boolean singleSession)

Set whether to use a single session for each request. Default is "true".

If set to false, each data access operation or transaction will use its own session (like without Open Session in View). Each of those sessions will be registered for deferred close, though, actually processed at request completion.

See Also:

SessionFactoryUtils.initDeferredClose(org.hibernate.SessionFactory), SessionFactoryUtils.processDeferredClose(org.hibernate.SessionFactory)

isSingleSession

protected boolean isSingleSession()

Return whether to use a single session for each request.

preHandle

public void preHandle(WebRequest request)
               throws DataAccessException

Open a new Hibernate Session according to the settings of this HibernateAccessor and bind it to the thread via the TransactionSynchronizationManager.

Specified by:

preHandle in interface WebRequestInterceptor

Parameters:

request - the current web request

Throws:

DataAccessException

See Also:

SessionFactoryUtils.getSession(org.hibernate.SessionFactory, boolean)

postHandle

public void postHandle(WebRequest request,
                       ModelMap model)
                throws DataAccessException

Flush the Hibernate Session before view rendering, if necessary.

Note that this just applies in single session mode!

The default is FLUSH_NEVER to avoid this extra flushing, assuming that service layer transactions have flushed their changes on commit.

Specified by:

postHandle in interface WebRequestInterceptor

Parameters:

request - the current web request

model - the map of model objects that will be exposed to the view (may be null). Can be used to analyze the exposed model and/or to add further model attributes, if desired.

Throws:

DataAccessException

See Also:

HibernateAccessor.setFlushMode(int)

afterCompletion

public void afterCompletion(WebRequest request,
                            Exception ex)
                     throws DataAccessException

Unbind the Hibernate Session from the thread and close it (in single session mode), or process deferred close for all sessions that have been opened during the current request (in deferred close mode).

Specified by:

afterCompletion in interface WebRequestInterceptor

Parameters:

request - the current web request

ex - exception thrown on handler execution, if any

Throws:

DataAccessException

See Also:

TransactionSynchronizationManager

getParticipateAttributeName

protected String getParticipateAttributeName()

Return the name of the request attribute that identifies that a request is already intercepted.

The default implementation takes the toString() representation of the SessionFactory instance and appends PARTICIPATE_SUFFIX.