OpenSessionInViewFilter

Class Overview

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).

Summary

[Expand] Inherited Constants
From class org.springframework.web.filter.OncePerRequestFilter String ALREADY_FILTERED_SUFFIX Suffix that gets appended to the filter name for the "already filtered" request attribute.

[Expand] Inherited Fields
From class org.springframework.web.filter.GenericFilterBean protected final Log logger Logger available to subclasses

[Expand] Inherited Methods
From class org.springframework.web.filter.OncePerRequestFilter final void doFilter(ServletRequest request, ServletResponse response, FilterChain filterChain) This doFilter implementation stores a request attribute for "already filtered", proceeding without filtering again if the attribute is already there. abstract void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain filterChain) Same contract as for doFilter, but guaranteed to be just invoked once per request. String getAlreadyFilteredAttributeName() Return the name of the request attribute that identifies that a request is already filtered. boolean shouldNotFilter(HttpServletRequest request) Can be overridden in subclasses for custom filtering control, returning true to avoid filtering of the given request.
From class org.springframework.web.filter.GenericFilterBean final void addRequiredProperty(String property) Subclasses can invoke this method to specify that this property (which must match a JavaBean property they expose) is mandatory, and must be supplied as a config parameter. void afterPropertiesSet() Calls the initFilterBean() method that might contain custom initialization of a subclass. void destroy() Subclasses may override this to perform custom filter shutdown. final FilterConfig getFilterConfig() Make the FilterConfig of this filter available, if any. final String getFilterName() Make the name of this filter available to subclasses. final ServletContext getServletContext() Make the ServletContext of this filter available to subclasses. final void init(FilterConfig filterConfig) Standard way of initializing this filter. void initBeanWrapper(BeanWrapper bw) Initialize the BeanWrapper for this GenericFilterBean, possibly with custom editors. void initFilterBean() Subclasses may override this to perform custom initialization. final void setBeanName(String beanName) Stores the bean name as defined in the Spring bean factory. void setEnvironment(Environment environment) Set the Environment that this object runs in. Any environment set here overrides the DefaultWebEnvironment provided by default. final void setServletContext(ServletContext servletContext) Stores the ServletContext that the bean factory runs in.
From class java.lang.Object Object clone() boolean equals(Object arg0) void finalize() final Class<?> getClass() int hashCode() final void notify() final void notifyAll() String toString() final void wait() final void wait(long arg0, int arg1) final void wait(long arg0)
From interface javax.servlet.Filter abstract void destroy() abstract void doFilter(ServletRequest arg0, ServletResponse arg1, FilterChain arg2) abstract void init(FilterConfig arg0)
From interface org.springframework.beans.factory.BeanNameAware abstract void setBeanName(String name) Set the name of the bean in the bean factory that created this bean.
From interface org.springframework.beans.factory.DisposableBean abstract void destroy() Invoked by a BeanFactory on destruction of a singleton.
From interface org.springframework.beans.factory.InitializingBean abstract void afterPropertiesSet() Invoked by a BeanFactory after it has set all bean properties supplied (and satisfied BeanFactoryAware and ApplicationContextAware).
From interface org.springframework.context.EnvironmentAware abstract void setEnvironment(Environment environment) Set the Environment that this object runs in.
From interface org.springframework.web.context.ServletContextAware abstract void setServletContext(ServletContext servletContext) Set the ServletContext that this object runs in.