org.springframework.orm.hibernate3.support
Class OpenSessionInViewFilter

java.lang.Object
  extended by org.springframework.web.filter.GenericFilterBean
      extended by org.springframework.web.filter.OncePerRequestFilter
          extended by org.springframework.orm.hibernate3.support.OpenSessionInViewFilter
All Implemented Interfaces:
Filter, BeanNameAware, DisposableBean, InitializingBean, ServletContextAware

public class OpenSessionInViewFilter
extends OncePerRequestFilter

Servlet 2.3 Filter that binds a Hibernate Session to the thread for the entire processing of the request. Intended for the "Open Session in View" pattern, i.e. to allow for lazy loading in web views despite the original transactions already being completed.

This filter works similar to the AOP HibernateInterceptor: It just makes Hibernate Sessions available via the thread. It is suitable for non-transactional execution but also for business layer transactions via HibernateTransactionManager or JtaTransactionManager. In the latter case, Sessions pre-bound by this filter will automatically be used for the transactions and flushed accordingly.

WARNING: Applying this filter 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 filter 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 (like without Open Session in View). Each of those sessions will be registered for deferred close, though, actually processed at request completion.

A single session per request allows for most efficient first-level caching, but can cause side effects, for example on saveOrUpdate or if 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).

Looks up the SessionFactory in Spring's root web application context. Supports a "sessionFactoryBeanName" filter init-param in web.xml; the default bean name is "sessionFactory". Looks up the SessionFactory on each request, to avoid initialization order issues (when using ContextLoaderServlet, the root application context will get initialized after this filter).

NOTE: This filter will by default not flush the Hibernate Session, as it assumes to be used in combination with service layer transactions that care for the flushing, or HibernateAccessors with flushMode FLUSH_EAGER. If you want this filter to flush after completed request processing, override closeSession and invoke flush on the Session before closing it. Additionally, you will also need to override getSession() to return a Session in a flush mode other than the default FlushMode.NEVER. Note that getSession and closeSession will just be invoked in single session mode!

Since:
1.2
Author:
Juergen Hoeller
See Also:
setSingleSession(boolean), closeSession(org.hibernate.Session, org.hibernate.SessionFactory), lookupSessionFactory(javax.servlet.http.HttpServletRequest), OpenSessionInViewInterceptor, HibernateInterceptor, HibernateTransactionManager, SessionFactoryUtils.getSession(org.hibernate.SessionFactory, boolean), TransactionSynchronizationManager

Field Summary
static String DEFAULT_SESSION_FACTORY_BEAN_NAME
           
 
Fields inherited from class org.springframework.web.filter.OncePerRequestFilter
ALREADY_FILTERED_SUFFIX
 
Fields inherited from class org.springframework.web.filter.GenericFilterBean
logger
 
Constructor Summary
OpenSessionInViewFilter()
           
 
Method Summary
protected  void closeSession(Session session, SessionFactory sessionFactory)
          Close the given Session.
protected  void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain filterChain)
          Same contract as for doFilter, but guaranteed to be just invoked once per request.
protected  FlushMode getFlushMode()
          Return the Hibernate flush mode to use for a single session managed by this filter.
protected  Session getSession(SessionFactory sessionFactory)
          Get a Session for the SessionFactory that this filter uses.
protected  String getSessionFactoryBeanName()
          Return the bean name of the SessionFactory to fetch from Spring's root application context.
protected  boolean isSingleSession()
          Return whether to use a single session for each request.
protected  SessionFactory lookupSessionFactory()
          Look up the SessionFactory that this filter should use.
protected  SessionFactory lookupSessionFactory(HttpServletRequest request)
          Look up the SessionFactory that this filter should use, taking the current HTTP request as argument.
 void setFlushMode(FlushMode flushMode)
          Specify the Hibernate flush mode to use for a single session managed by this filter.
 void setSessionFactoryBeanName(String sessionFactoryBeanName)
          Set the bean name of the SessionFactory to fetch from Spring's root application context.
 void setSingleSession(boolean singleSession)
          Set whether to use a single session for each request.
 
Methods inherited from class org.springframework.web.filter.OncePerRequestFilter
doFilter, getAlreadyFilteredAttributeName, shouldNotFilter
 
Methods inherited from class org.springframework.web.filter.GenericFilterBean
addRequiredProperty, afterPropertiesSet, destroy, getFilterConfig, getFilterName, getServletContext, init, initBeanWrapper, initFilterBean, setBeanName, setFilterConfig, setServletContext
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

DEFAULT_SESSION_FACTORY_BEAN_NAME

public static final String DEFAULT_SESSION_FACTORY_BEAN_NAME
See Also:
Constant Field Values
Constructor Detail

OpenSessionInViewFilter

public OpenSessionInViewFilter()
Method Detail

setSessionFactoryBeanName

public void setSessionFactoryBeanName(String sessionFactoryBeanName)
Set the bean name of the SessionFactory to fetch from Spring's root application context. Default is "sessionFactory".

See Also:
DEFAULT_SESSION_FACTORY_BEAN_NAME

getSessionFactoryBeanName

protected String getSessionFactoryBeanName()
Return the bean name of the SessionFactory to fetch from Spring's root application context.


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.


setFlushMode

public void setFlushMode(FlushMode flushMode)
Specify the Hibernate flush mode to use for a single session managed by this filter. Supported values are all FlushMode constants, which can simply be specified as String value: e.g. "AUTO".

Default is "NEVER", not allowing any flushes outside of a transaction.

See Also:
FlushMode.AUTO, FlushMode.NEVER

getFlushMode

protected FlushMode getFlushMode()
Return the Hibernate flush mode to use for a single session managed by this filter.


doFilterInternal

protected void doFilterInternal(HttpServletRequest request,
                                HttpServletResponse response,
                                FilterChain filterChain)
                         throws ServletException,
                                IOException
Description copied from class: OncePerRequestFilter
Same contract as for doFilter, but guaranteed to be just invoked once per request. Provides HttpServletRequest and HttpServletResponse arguments instead of the default ServletRequest and ServletResponse ones.

Specified by:
doFilterInternal in class OncePerRequestFilter
Throws:
ServletException
IOException

lookupSessionFactory

protected SessionFactory lookupSessionFactory(HttpServletRequest request)
Look up the SessionFactory that this filter should use, taking the current HTTP request as argument.

Default implementation delegates to the lookupSessionFactory without arguments.

Returns:
the SessionFactory to use
See Also:
lookupSessionFactory()

lookupSessionFactory

protected SessionFactory lookupSessionFactory()
Look up the SessionFactory that this filter should use.

Default implementation looks for a bean with the specified name in Spring's root application context.

Returns:
the SessionFactory to use
See Also:
getSessionFactoryBeanName()

getSession

protected Session getSession(SessionFactory sessionFactory)
                      throws DataAccessResourceFailureException
Get a Session for the SessionFactory that this filter uses. Note that this just applies in single session mode!

The default implementation delegates to the SessionFactoryUtils.getSession method and sets the Session's flush mode to "NEVER".

Can be overridden in subclasses for creating a Session with a custom entity interceptor or JDBC exception translator.

Parameters:
sessionFactory - the SessionFactory that this filter uses
Returns:
the Session to use
Throws:
DataAccessResourceFailureException - if the Session could not be created
See Also:
SessionFactoryUtils.getSession(SessionFactory, boolean), FlushMode.NEVER

closeSession

protected void closeSession(Session session,
                            SessionFactory sessionFactory)
Close the given Session. Note that this just applies in single session mode!

Can be overridden in subclasses, e.g. for flushing the Session before closing it. See class-level javadoc for a discussion of flush handling. Note that you should also override getSession accordingly, to set the flush mode to something else than NEVER.

Parameters:
session - the Session used for filtering
sessionFactory - the SessionFactory that this filter uses


Copyright (c) 2002-2007 The Spring Framework Project.