RequestAttributes (Spring Framework API 2.1) - Spring Framework 2.1.0 API 文档英文版

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org.springframework.web.context.request
Interface RequestAttributes

All Known Subinterfaces:: WebRequest

All Known Implementing Classes:: AbstractRequestAttributes, DispatcherServletWebRequest, PortletRequestAttributes, PortletWebRequest, ServletRequestAttributes, ServletWebRequest

public interface RequestAttributes

Abstraction for accessing attribute objects associated with a request. Supports access to request-scoped attributes as well as to session-scoped attributes, with the optional notion of a "global session".

Can be implemented for any kind of request/session mechanism, in particular for servlet requests and portlet requests.

Since:: 2.0
Author:: Juergen Hoeller
See Also:: ServletRequestAttributes, PortletRequestAttributes

Field Summary

static int SCOPE_GLOBAL_SESSION
          Constant that indicates global session scope.

static int SCOPE_REQUEST
          Constant that indicates request scope.

static int SCOPE_SESSION
          Constant that indicates session scope.

Method Summary

Object getAttribute(String name, int scope)
          Return the value for the scoped attribute of the given name, if any.

String getSessionId()
          Return an id for the current underlying session.

Object getSessionMutex()
          Expose the best available mutex for the underlying session: that is, an object to synchronize on for the underlying session.

void registerDestructionCallback(String name, Runnable callback, int scope)
          Register a callback to be executed on destruction of the specified attribute in the given scope.

void removeAttribute(String name, int scope)
          Remove the scoped attribute of the given name, if it exists.

void setAttribute(String name, Object value, int scope)
          Set the value for the scoped attribute of the given name, replacing an existing value (if any).

Field Summary
`static int`	`SCOPE_GLOBAL_SESSION` Constant that indicates global session scope.
`static int`	`SCOPE_REQUEST` Constant that indicates request scope.
`static int`	`SCOPE_SESSION` Constant that indicates session scope.

Method Summary
`Object`	`getAttribute(String name, int scope)` Return the value for the scoped attribute of the given name, if any.
`String`	`getSessionId()` Return an id for the current underlying session.
`Object`	`getSessionMutex()` Expose the best available mutex for the underlying session: that is, an object to synchronize on for the underlying session.
`void`	`registerDestructionCallback(String name, Runnable callback, int scope)` Register a callback to be executed on destruction of the specified attribute in the given scope.
`void`	`removeAttribute(String name, int scope)` Remove the scoped attribute of the given name, if it exists.
`void`	`setAttribute(String name, Object value, int scope)` Set the value for the scoped attribute of the given name, replacing an existing value (if any).

Field Detail

SCOPE_REQUEST

static final int SCOPE_REQUEST

Constant that indicates request scope.

See Also:: Constant Field Values

SCOPE_SESSION

static final int SCOPE_SESSION

Constant that indicates session scope.

This preferably refers to a locally isolated session, if such a distinction is available (for example, in a Portlet environment). Else, it simply refers to the common session.

See Also:: Constant Field Values

SCOPE_GLOBAL_SESSION

static final int SCOPE_GLOBAL_SESSION

Constant that indicates global session scope.

This explicitly refers to a globally shared session, if such a distinction is available (for example, in a Portlet environment). Else, it simply refers to the common session.

See Also:: Constant Field Values

Method Detail

getAttribute

Object getAttribute(String name,
                    int scope)

Return the value for the scoped attribute of the given name, if any.

Parameters:: name - the name of the attribute; scope - the scope identifier
Returns:: the current attribute value, or null if not found

setAttribute

void setAttribute(String name,
                  Object value,
                  int scope)

Set the value for the scoped attribute of the given name, replacing an existing value (if any).

Parameters:: name - the name of the attribute; scope - the scope identifier; value - the value for the attribute

removeAttribute

void removeAttribute(String name,
                     int scope)

Remove the scoped attribute of the given name, if it exists.

Note that an implementation should also remove a registered destruction callback for the specified attribute, 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).

Parameters:: name - the name of the attribute; scope - the scope identifier

registerDestructionCallback

void registerDestructionCallback(String name,
                                 Runnable callback,
                                 int scope)

Implementations should do their best to execute the callback at the appropriate time: that is, at request completion or session termination, respectively. If such a callback is not supported by the underlying runtime environment, the callback must be ignored and a corresponding warning should be logged.

Note that 'destruction' usually corresponds to destruction of the entire scope, not to the individual attribute having been explicitly removed by the application. If an attribute gets removed via this facade's removeAttribute(String, int) method, any registered destruction callback should be disabled as well, assuming that the removed object will be reused or manually destroyed.

Parameters:: name - the name of the attribute to register the callback for; callback - the destruction callback to be executed; scope - the scope identifier

getSessionId

String getSessionId()

Return an id for the current underlying session.

Returns:: the session id as String (never null

getSessionMutex

Object getSessionMutex()

Expose the best available mutex for the underlying session: that is, an object to synchronize on for the underlying session.

Returns:: the session mutex to use (never null