接口 RequestAttributes

字段详细资料

• SCOPE_REQUEST

  static final int SCOPE_REQUEST

  Constant that indicates request scope.

  另请参阅:

  常量字段值

• 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.

  另请参阅:

  常量字段值

• 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.

  另请参阅:

  常量字段值

• REFERENCE_REQUEST

  static final String REFERENCE_REQUEST

  Name of the standard reference to the request object: "request".

  另请参阅:

  resolveReference(java.lang.String), 常量字段值

• REFERENCE_SESSION

  static final String REFERENCE_SESSION

  Name of the standard reference to the session object: "session".

  另请参阅:

  resolveReference(java.lang.String), 常量字段值

方法详细资料

• getAttribute

  Object getAttribute​(String name,
                      int scope)

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

  参数:

  name - the name of the attribute

  scope - the scope identifier

  返回:

  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).

  参数:

  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).

  参数:

  name - the name of the attribute

  scope - the scope identifier

• getAttributeNames

  String[] getAttributeNames​(int scope)

  Retrieve the names of all attributes in the scope.

  参数:

  scope - the scope identifier

  返回:

  the attribute names as String array

• registerDestructionCallback

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

  Register a callback to be executed on destruction of the specified attribute in the given 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.

  NOTE: Callback objects should generally be serializable if they are being registered for a session scope. Otherwise the callback (or even the entire session) might not survive web app restarts.

  参数:

  name - the name of the attribute to register the callback for

  callback - the destruction callback to be executed

  scope - the scope identifier

• resolveReference

  Object resolveReference​(String key)

  Resolve the contextual reference for the given key, if any.

  At a minimum: the HttpServletRequest/PortletRequest reference for key "request", and the HttpSession/PortletSession reference for key "session".

  参数:

  key - the contextual key

  返回:

  the corresponding object, or null if none found

• getSessionId

  String getSessionId()

  Return an id for the current underlying session.

  返回:

  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.

  返回:

  the session mutex to use (never null)