org.springframework.web.context.request
Interface RequestAttributes

All Known Subinterfaces:
NativeWebRequest, WebRequest
All Known Implementing Classes:
AbstractRequestAttributes, DispatcherServletWebRequest, FacesRequestAttributes, FacesWebRequest, 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 java.lang.String REFERENCE_REQUEST
           
static java.lang.String REFERENCE_SESSION
           
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
 java.lang.Object getAttribute(java.lang.String name, int scope)
          Return the value for the scoped attribute of the given name, if any.
 java.lang.String[] getAttributeNames(int scope)
          Retrieve the names of all attributes in the scope.
 java.lang.String getSessionId()
          Return an id for the current underlying session.
 java.lang.Object getSessionMutex()
          Expose the best available mutex for the underlying session: that is, an object to synchronize on for the underlying session.
 void registerDestructionCallback(java.lang.String name, java.lang.Runnable callback, int scope)
          Register a callback to be executed on destruction of the specified attribute in the given scope.
 void removeAttribute(java.lang.String name, int scope)
          Remove the scoped attribute of the given name, if it exists.
 java.lang.Object resolveReference(java.lang.String key)
          Resolve the contextual reference for the given key, if any.
 void setAttribute(java.lang.String name, java.lang.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

REFERENCE_REQUEST

static final java.lang.String REFERENCE_REQUEST
See Also:
Constant Field Values

REFERENCE_SESSION

static final java.lang.String REFERENCE_SESSION
See Also:
Constant Field Values
Method Detail

getAttribute

java.lang.Object getAttribute(java.lang.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(java.lang.String name,
                  java.lang.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(java.lang.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

getAttributeNames

java.lang.String[] getAttributeNames(int scope)
Retrieve the names of all attributes in the scope.

Parameters:
scope - the scope identifier
Returns:
the attribute names as String array

registerDestructionCallback

void registerDestructionCallback(java.lang.String name,
                                 java.lang.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.

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

resolveReference

java.lang.Object resolveReference(java.lang.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".

Parameters:
key - the contextual key
Returns:
the corresponding object, or null if none found

getSessionId

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

Returns:
the session id as String (never null

getSessionMutex

java.lang.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