The Spring Framework

## org.springframework.orm.hibernate3.support
Class OpenSessionInViewFilter

    java.lang.Object
      org.springframework.web.filter.GenericFilterBean
          org.springframework.web.filter.OncePerRequestFilter
              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 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 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 FlushMode that this filter applies to its `Session` (in single session mode).
`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 FlushMode to apply to this filter's `Session`.
`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, 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 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 "NEVER". Specify "AUTO" if you intend to use this filter without service layer transactions.

  See Also:
    `Session.setFlushMode(org.hibernate.FlushMode)`, `FlushMode.NEVER`, `FlushMode.AUTO`

### getFlushMode

    protected FlushMode getFlushMode()

  Return the Hibernate FlushMode that this filter applies to its `Session` (in single session mode).

### 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.

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

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

### lookupSessionFactory

    protected 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 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

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