## org.springframework.orm.jpa.support
Class OpenEntityManagerInViewInterceptor

    java.lang.Object
      org.springframework.orm.jpa.EntityManagerFactoryAccessor
          org.springframework.orm.jpa.support.OpenEntityManagerInViewInterceptor

All Implemented Interfaces:
  WebRequestInterceptor

    public class OpenEntityManagerInViewInterceptor

extends EntityManagerFactoryAccessor
implements WebRequestInterceptor

Spring web request interceptor that binds a JPA EntityManager to the thread for the entire processing of the request. Intended for the "Open EntityManager in View" pattern, i.e. to allow for lazy loading in web views despite the original transactions already being completed.

This interceptor makes JPA EntityManagers available via the current thread, which will be autodetected by transaction managers. It is suitable for service layer transactions via `JpaTransactionManager` or `JtaTransactionManager` as well as for non-transactional read-only execution.

In contrast to `OpenEntityManagerInViewFilter`, this interceptor is set up in a Spring application context and can thus take advantage of bean wiring. It inherits common JPA configuration properties from `JpaAccessor`, to be configured in a bean definition.

Since:
  2.0
Author:
  Juergen Hoeller
See Also:
  `OpenEntityManagerInViewFilter`, `JpaInterceptor`, `JpaTransactionManager`, `JpaTemplate.execute(org.springframework.orm.jpa.JpaCallback)`, `SharedEntityManagerCreator`, `TransactionSynchronizationManager`

Field Summary
`static String` `PARTICIPATE_SUFFIX` Suffix that gets appended to the EntityManagerFactory toString representation for the "participate in existing entity manager handling" request attribute.

Fields inherited from class org.springframework.orm.jpa.EntityManagerFactoryAccessor
`logger`

Constructor Summary
`OpenEntityManagerInViewInterceptor()`

Method Summary
`void` `afterCompletion(WebRequest request, Exception ex)` Callback after completion of request processing, that is, after rendering the view.
`protected String` `getParticipateAttributeName()` Return the name of the request attribute that identifies that a request is already filtered.
`void` `postHandle(WebRequest request, ModelMap model)` Intercept the execution of a request handler after its successful invocation, right before view rendering (if any).
`void` `preHandle(WebRequest request)` Intercept the execution of a request handler before its invocation.

Methods inherited from class org.springframework.orm.jpa.EntityManagerFactoryAccessor
`createEntityManager, getEntityManagerFactory, getJpaPropertyMap, getTransactionalEntityManager, setEntityManagerFactory, setJpaProperties, setJpaPropertyMap`

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 EntityManagerFactory toString representation for the "participate in existing entity manager handling" request attribute.

  See Also:
    `getParticipateAttributeName()`, Constant Field Values

Constructor Detail

### OpenEntityManagerInViewInterceptor

    public OpenEntityManagerInViewInterceptor()

Method Detail

### preHandle

    public void preHandle(WebRequest request)
                   throws DataAccessException

  Description copied from interface: `WebRequestInterceptor`
  Intercept the execution of a request handler before its invocation.

  Allows for preparing context resources (such as a Hibernate Session) and expose them as request attributes or as thread-local objects.

  Specified by:
    `preHandle` in interface `WebRequestInterceptor`
  Parameters:
    `request` - the current web request
  Throws:
    `DataAccessException`

### postHandle

    public void postHandle(WebRequest request,
                           ModelMap model)

  Description copied from interface: `WebRequestInterceptor`
  Intercept the execution of a request handler after its successful invocation, right before view rendering (if any).

  Allows for modifying context resources after successful handler execution (for example, flushing a Hibernate Session).

  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.

### afterCompletion

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

  Description copied from interface: `WebRequestInterceptor`
  Callback after completion of request processing, that is, after rendering the view. Will be called on any outcome of handler execution, thus allows for proper resource cleanup.

  Note: Will only be called if this interceptor's `preHandle` method has successfully completed!

  Specified by:
    `afterCompletion` in interface `WebRequestInterceptor`
  Parameters:
    `request` - the current web request
    `ex` - exception thrown on handler execution, if any
  Throws:
    `DataAccessException`

### getParticipateAttributeName

    protected String getParticipateAttributeName()

  Return the name of the request attribute that identifies that a request is already filtered. Default implementation takes the toString representation of the EntityManagerFactory instance and appends ".FILTERED".

  See Also:
    `PARTICIPATE_SUFFIX`

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