org.springframework.context.support

Class SimpleThreadScope

java.lang.Object

org.springframework.context.support.SimpleThreadScope

All Implemented Interfaces:

Scope

public class SimpleThreadScope
extends Object
implements Scope

A simple thread-backed Scope implementation.

NOTE: This thread scope is not registered by default in common contexts. Instead, you need to explicitly assign it to a scope key in your setup, either through ConfigurableBeanFactory.registerScope(java.lang.String, org.springframework.beans.factory.config.Scope) or through a CustomScopeConfigurer bean.

SimpleThreadScope does not clean up any objects associated with it. It is therefore typically preferable to use a request-bound scope implementation such as org.springframework.web.context.request.RequestScope in web environments, implementing the full lifecycle for scoped attributes (including reliable destruction).

For an implementation of a thread-based Scope with support for destruction callbacks, refer to Spring by Example.

Thanks to Eugene Kuleshov for submitting the original prototype for a thread scope!

Since:

3.0

Author:

Arjen Poutsma, Juergen Hoeller

See Also:

RequestScope

Constructor Summary

Constructors

Constructor and Description
SimpleThreadScope()

Method Summary

Modifier and Type	Method and Description
Object	get(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.
String	getConversationId() Return the conversation ID for the current underlying scope, if any.
void	registerDestructionCallback(String name, 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).
Object	remove(String name) Remove the object with the given name from the underlying scope.
Object	resolveContextualObject(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

Constructor Detail

SimpleThreadScope

public SimpleThreadScope()

Method Detail

get

public Object get(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

@Nullable
public Object remove(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(String name,
                                        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 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

@Nullable
public Object resolveContextualObject(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

getConversationId

public String getConversationId()

Description copied from interface: Scope

Return the conversation ID for the current underlying scope, if any.

The exact meaning of the conversation ID depends on the underlying storage mechanism. In the case of session-scoped objects, the conversation ID would typically be equal to (or derived from) the session ID; in the case of a custom conversation that sits within the overall session, the specific ID for the current conversation would be appropriate.

Note: This is an optional operation. It is perfectly valid to return null in an implementation of this method if the underlying storage mechanism has no obvious candidate for such an ID.

Specified by:

getConversationId in interface Scope

Returns:

the conversation ID, or null if there is no conversation ID for the current scope