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

org.springframework.web.context.request

## Class ServletRequestAttributes

- java.lang.Object
- - org.springframework.web.context.request.AbstractRequestAttributes
  - - org.springframework.web.context.request.ServletRequestAttributes

- All Implemented Interfaces:
    RequestAttributes
  Direct Known Subclasses:
    ServletWebRequest

      public class ServletRequestAttributes
      extends AbstractRequestAttributes

  Servlet-based implementation of the `RequestAttributes` interface.

  Accesses objects from servlet request and HTTP session scope, with no distinction between "session" and "global session".

  Since:
    2.0
  Author:
    Juergen Hoeller
  See Also:
    `ServletRequest.getAttribute(java.lang.String)`, `HttpSession.getAttribute(java.lang.String)`

- - ### Field Summary

    Fields
    Modifier and Type | Field and Description
    --- | ---
    `static String` | `DESTRUCTION_CALLBACK_NAME_PREFIX` Constant identifying the `String` prefixed to the name of a destruction callback when it is stored in a `HttpSession`.

    - ### Fields inherited from class org.springframework.web.context.request.AbstractRequestAttributes

      `requestDestructionCallbacks`

    - ### 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
    `ServletRequestAttributes(HttpServletRequest request)` Create a new ServletRequestAttributes instance for the given request.

  - ### 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.
    `String[]` | `getAttributeNames(int scope)` Retrieve the names of all attributes in the scope.
    `HttpServletRequest` | `getRequest()` Exposes the native `HttpServletRequest` that we're wrapping.
    `protected HttpSession` | `getSession(boolean allowCreate)` Exposes the `HttpSession` that we're wrapping.
    `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.
    `protected void` | `registerSessionDestructionCallback(String name, Runnable callback)` Register the given callback as to be executed after session termination.
    `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).
    `String` | `toString()`
    `protected void` | `updateAccessedSessionAttributes()` Update all accessed session attributes through `session.setAttribute` calls, explicitly indicating to the container that they might have been modified.

    - ### Methods inherited from class org.springframework.web.context.request.AbstractRequestAttributes

      `isRequestActive, registerRequestDestructionCallback, removeRequestDestructionCallback, requestCompleted`

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

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

- - ### Field Detail

    - #### DESTRUCTION_CALLBACK_NAME_PREFIX

          public static final String DESTRUCTION_CALLBACK_NAME_PREFIX

      Constant identifying the `String` prefixed to the name of a destruction callback when it is stored in a `HttpSession`.

  - ### Constructor Detail

    - #### ServletRequestAttributes

          public ServletRequestAttributes(HttpServletRequest request)

      Create a new ServletRequestAttributes instance for the given request.
      Parameters:
        `request` - current HTTP request

  - ### Method Detail

    - #### getRequest

          public final HttpServletRequest getRequest()

      Exposes the native `HttpServletRequest` that we're wrapping.

    - #### getSession

          protected final HttpSession getSession(boolean allowCreate)

      Exposes the `HttpSession` that we're wrapping.
      Parameters:
        `allowCreate` - whether to allow creation of a new session if none exists yet

    - #### 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.
      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).
      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).

      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.
      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.

      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".

      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.
      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.
      Returns:
        the session mutex to use (never `null`

    - #### updateAccessedSessionAttributes

          protected void updateAccessedSessionAttributes()

      Update all accessed session attributes through `session.setAttribute` calls, explicitly indicating to the container that they might have been modified.
      Specified by:
        `updateAccessedSessionAttributes` in class `AbstractRequestAttributes`

    - #### registerSessionDestructionCallback

          protected void registerSessionDestructionCallback(String name,
                                                Runnable callback)

      Register the given callback as to be executed after session termination.

      Note: The callback object should be serializable in order to survive web app restarts.

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

    - #### toString

          public String toString()

      Overrides:
        `toString` in class `Object`