FacesRequestAttributes (Spring Framework 3.2.1.RELEASE API)
Date: 2013-01-24

org.springframework.web.context.request

## Class FacesRequestAttributes

- java.lang.Object
- - org.springframework.web.context.request.FacesRequestAttributes

- All Implemented Interfaces:
    RequestAttributes
  Direct Known Subclasses:
    FacesWebRequest

      public class FacesRequestAttributes
      extends Object
      implements RequestAttributes

  `RequestAttributes` adapter for a JSF `FacesContext`. Used as default in a JSF environment, wrapping the current FacesContext.

  NOTE: In contrast to `ServletRequestAttributes`, this variant does not support destruction callbacks for scoped attributes, neither for the request scope nor for the session scope. If you rely on such implicit destruction callbacks, consider defining a Spring `RequestContextListener` in your `web.xml`.

  Since:
    2.5.2
  Author:
    Juergen Hoeller
  See Also:
    `FacesContext.getExternalContext()`, `ExternalContext.getRequestMap()`, `ExternalContext.getSessionMap()`, `RequestContextHolder.currentRequestAttributes()`

- - ### Field Summary

    - ### Fields inherited from interface org.springframework.web.context.request.RequestAttributes

      `REFERENCE_REQUEST, REFERENCE_SESSION, SCOPE_GLOBAL_SESSION, SCOPE_REQUEST, SCOPE_SESSION`

  - ### Constructor Summary

    Constructors
    Constructor and Description
    `FacesRequestAttributes(FacesContext facesContext)` Create a new FacesRequestAttributes adapter for the given FacesContext.

  - ### Method Summary

    Methods
    Modifier and Type | Method and Description
    --- | ---
    `Object` | `getAttribute(String name, int scope)` Return the value for the scoped attribute of the given name, if any.
    `protected Map<String,Object>` | `getAttributeMap(int scope)` Return the JSF attribute Map for the specified scope
    `String[]` | `getAttributeNames(int scope)` Retrieve the names of all attributes in the scope.
    `protected ExternalContext` | `getExternalContext()` Return the JSF ExternalContext that this adapter operates on.
    `protected FacesContext` | `getFacesContext()` Return the JSF FacesContext that this adapter operates on.
    `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.
    `Object` | `resolveReference(String key)` Resolve the contextual reference for the given key, if any.
    `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).

    - ### Methods inherited from class java.lang.Object

      `clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

- - ### Constructor Detail

    - #### FacesRequestAttributes

          public FacesRequestAttributes(FacesContext facesContext)

      Create a new FacesRequestAttributes adapter for the given FacesContext.
      Parameters:
        `facesContext` - the current FacesContext
      See Also:
        `FacesContext.getCurrentInstance()`

  - ### Method Detail

    - #### getFacesContext

          protected final FacesContext getFacesContext()

      Return the JSF FacesContext that this adapter operates on.

    - #### getExternalContext

          protected final ExternalContext getExternalContext()

      Return the JSF ExternalContext that this adapter operates on.
      See Also:
        `FacesContext.getExternalContext()`

    - #### getAttributeMap

          protected Map<String,Object> getAttributeMap(int scope)

      Return the JSF attribute Map for the specified scope
      Parameters:
        `scope` - constant indicating request or session scope
      Returns:
        the Map representation of the attributes in the specified scope
      See Also:
        `RequestAttributes.SCOPE_REQUEST`, `RequestAttributes.SCOPE_SESSION`

    - #### getAttribute

          public Object getAttribute(String name,
                            int scope)

      Description copied from interface: `RequestAttributes`
      Return the value for the scoped attribute of the given name, if any.
      Specified by:
        `getAttribute` in interface `RequestAttributes`
      Parameters:
        `name` - the name of the attribute
        `scope` - the scope identifier
      Returns:
        the current attribute value, or `null` if not found

    - #### setAttribute

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

      Description copied from interface: `RequestAttributes`
      Set the value for the scoped attribute of the given name, replacing an existing value (if any).
      Specified by:
        `setAttribute` in interface `RequestAttributes`
      Parameters:
        `name` - the name of the attribute
        `value` - the value for the attribute
        `scope` - the scope identifier

    - #### removeAttribute

          public void removeAttribute(String name,
                             int scope)

      Description copied from interface: `RequestAttributes`
      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).

      Specified by:
        `removeAttribute` in interface `RequestAttributes`
      Parameters:
        `name` - the name of the attribute
        `scope` - the scope identifier

    - #### getAttributeNames

          public String[] getAttributeNames(int scope)

      Description copied from interface: `RequestAttributes`
      Retrieve the names of all attributes in the scope.
      Specified by:
        `getAttributeNames` in interface `RequestAttributes`
      Parameters:
        `scope` - the scope identifier
      Returns:
        the attribute names as String array

    - #### registerDestructionCallback

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

      Description copied from interface: `RequestAttributes`
      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 `RequestAttributes.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.

      Specified by:
        `registerDestructionCallback` in interface `RequestAttributes`
      Parameters:
        `name` - the name of the attribute to register the callback for
        `callback` - the destruction callback to be executed
        `scope` - the scope identifier

    - #### resolveReference

          public Object resolveReference(String key)

      Description copied from interface: `RequestAttributes`
      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".

      Specified by:
        `resolveReference` in interface `RequestAttributes`
      Parameters:
        `key` - the contextual key
      Returns:
        the corresponding object, or `null` if none found

    - #### getSessionId

          public String getSessionId()

      Description copied from interface: `RequestAttributes`
      Return an id for the current underlying session.
      Specified by:
        `getSessionId` in interface `RequestAttributes`
      Returns:
        the session id as String (never `null`

    - #### getSessionMutex

          public Object getSessionMutex()

      Description copied from interface: `RequestAttributes`
      Expose the best available mutex for the underlying session: that is, an object to synchronize on for the underlying session.
      Specified by:
        `getSessionMutex` in interface `RequestAttributes`
      Returns:
        the session mutex to use (never `null`