Spring Framework

org.springframework.web.context.request
Class AbstractRequestAttributesScope

java.lang.Object
  extended by org.springframework.web.context.request.AbstractRequestAttributesScope
All Implemented Interfaces:
Scope
Direct Known Subclasses:
RequestScope, SessionScope

public abstract class AbstractRequestAttributesScope
extends java.lang.Object
implements Scope

Abstract Scope implementation that reads from a particular scope in the current thread-bound RequestAttributes object.

Subclasses simply need to implement getScope() to instruct this class which RequestAttributes scope to read attributes from.

Subclasses may wish to override the get(java.lang.String, org.springframework.beans.factory.ObjectFactory) and remove(java.lang.String) methods to add synchronization around the call back into this super class.

Since:
2.0
Author:
Rod Johnson, Juergen Hoeller, Rob Harrop

Constructor Summary
AbstractRequestAttributesScope()
           
 
Method Summary
 java.lang.Object get(java.lang.String name, ObjectFactory objectFactory)
          Return the object with the given name from the underlying scope, creating it if not found in the underlying storage mechanism.
protected abstract  int getScope()
          Template method that determines the actual target scope.
 void registerDestructionCallback(java.lang.String name, java.lang.Runnable callback)
          Register a callback to be executed on destruction of the specified object in the scope (or at destruction of the entire scope, if the scope does not destroy individual objects but rather only terminates in its entirety).
 java.lang.Object remove(java.lang.String name)
          Remove the object with the given name from the underlying scope.
 java.lang.Object resolveContextualObject(java.lang.String key)
          Resolve the contextual object for the given key, if any.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 
Methods inherited from interface org.springframework.beans.factory.config.Scope
getConversationId
 

Constructor Detail

AbstractRequestAttributesScope

public AbstractRequestAttributesScope()
Method Detail

get

public java.lang.Object get(java.lang.String name,
                            ObjectFactory objectFactory)
Description copied from interface: Scope
Return the object with the given name from the underlying scope, creating it if not found in the underlying storage mechanism.

This is the central operation of a Scope, and the only operation that is absolutely required.

Specified by:
get in interface Scope
Parameters:
name - the name of the object to retrieve
objectFactory - the ObjectFactory to use to create the scoped object if it is not present in the underlying storage mechanism
Returns:
the desired object (never null)

remove

public java.lang.Object remove(java.lang.String name)
Description copied from interface: Scope
Remove the object with the given name from the underlying scope.

Returns null if no object was found; otherwise returns the removed Object.

Note that an implementation should also remove a registered destruction callback for the specified object, if any. It does, however, not need to execute a registered destruction callback in this case, since the object will be destroyed by the caller (if appropriate).

Note: This is an optional operation. Implementations may throw UnsupportedOperationException if they do not support explicitly removing an object.

Specified by:
remove in interface Scope
Parameters:
name - the name of the object to remove
Returns:
the removed object, or null if no object was present
See Also:
Scope.registerDestructionCallback(java.lang.String, java.lang.Runnable)

registerDestructionCallback

public void registerDestructionCallback(java.lang.String name,
                                        java.lang.Runnable callback)
Description copied from interface: Scope
Register a callback to be executed on destruction of the specified object in the scope (or at destruction of the entire scope, if the scope does not destroy individual objects but rather only terminates in its entirety).

Note: This is an optional operation. This method will only be called for scoped beans with actual destruction configuration (DisposableBean, destroy-method, DestructionAwareBeanPostProcessor). Implementations should do their best to execute a given callback at the appropriate time. If such a callback is not supported by the underlying runtime environment at all, the callback must be ignored and a corresponding warning should be logged.

Note that 'destruction' refers to to automatic destruction of the object as part of the scope's own lifecycle, not to the individual scoped object having been explicitly removed by the application. If a scoped object gets removed via this facade's Scope.remove(String) method, any registered destruction callback should be removed as well, assuming that the removed object will be reused or manually destroyed.

Specified by:
registerDestructionCallback in interface Scope
Parameters:
name - the name of the object to execute the destruction callback for
callback - the destruction callback to be executed. Note that the passed-in Runnable will never throw an exception, so it can safely be executed without an enclosing try-catch block. Furthermore, the Runnable will usually be serializable, provided that its target object is serializable as well.
See Also:
DisposableBean, AbstractBeanDefinition.getDestroyMethodName(), DestructionAwareBeanPostProcessor

resolveContextualObject

public java.lang.Object resolveContextualObject(java.lang.String key)
Description copied from interface: Scope
Resolve the contextual object for the given key, if any. E.g. the HttpServletRequest object for key "request".

Specified by:
resolveContextualObject in interface Scope
Parameters:
key - the contextual key
Returns:
the corresponding object, or null if none found

getScope

protected abstract int getScope()
Template method that determines the actual target scope.

Returns:
the target scope, in the form of an appropriate RequestAttributes constant
See Also:
RequestAttributes.SCOPE_REQUEST, RequestAttributes.SCOPE_SESSION, RequestAttributes.SCOPE_GLOBAL_SESSION

Spring Framework