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:
javax.servlet.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 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 filter will by default not flush the Hibernate Session, with the flush mode set to FlushMode.NEVER. It assumes to be used in combination with service layer transactions that care for 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 filter without transactions, consider changing the default flush mode (through the "flushMode" property).

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 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).

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).

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

Field Summary
static java.lang.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(org.hibernate.Session session, org.hibernate.SessionFactory sessionFactory)
          Close the given Session.
protected  void doFilterInternal(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response, javax.servlet.FilterChain filterChain)
          Same contract as for doFilter, but guaranteed to be just invoked once per request.
protected  org.hibernate.FlushMode getFlushMode()
          Return the Hibernate FlushMode that this filter applies to its Session (in single session mode).
protected  org.hibernate.Session getSession(org.hibernate.SessionFactory sessionFactory)
          Get a Session for the SessionFactory that this filter uses.
protected  java.lang.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  org.hibernate.SessionFactory lookupSessionFactory()
          Look up the SessionFactory that this filter should use.
protected  org.hibernate.SessionFactory lookupSessionFactory(javax.servlet.http.HttpServletRequest request)
          Look up the SessionFactory that this filter should use, taking the current HTTP request as argument.
 void setFlushMode(org.hibernate.FlushMode flushMode)
          Specify the Hibernate FlushMode to apply to this filter's Session.
 void setSessionFactoryBeanName(java.lang.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, 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 java.lang.String DEFAULT_SESSION_FACTORY_BEAN_NAME
See Also:
Constant Field Values
Constructor Detail

OpenSessionInViewFilter

public OpenSessionInViewFilter()
Method Detail

setSessionFactoryBeanName

public void setSessionFactoryBeanName(java.lang.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 java.lang.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(org.hibernate.FlushMode flushMode)
Specify the Hibernate FlushMode to apply to this filter's Session. Only applied in single session mode.

Can be populated with the corresponding constant name in XML bean definitions: e.g. "AUTO".

The default is "MANUAL". Specify "AUTO" if you intend to use this filter without service layer transactions.

See Also:
Session.setFlushMode(org.hibernate.FlushMode), FlushMode.MANUAL, FlushMode.AUTO

getFlushMode

protected org.hibernate.FlushMode getFlushMode()
Return the Hibernate FlushMode that this filter applies to its Session (in single session mode).


doFilterInternal

protected void doFilterInternal(javax.servlet.http.HttpServletRequest request,
                                javax.servlet.http.HttpServletResponse response,
                                javax.servlet.FilterChain filterChain)
                         throws javax.servlet.ServletException,
                                java.io.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:
javax.servlet.ServletException
java.io.IOException

lookupSessionFactory

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

The default implementation delegates to the lookupSessionFactory() variant without arguments.

Parameters:
request - the current request
Returns:
the SessionFactory to use

lookupSessionFactory

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

The 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 org.hibernate.Session getSession(org.hibernate.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 "MANUAL".

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.MANUAL

closeSession

protected void closeSession(org.hibernate.Session session,
                            org.hibernate.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