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

org.springframework.web.portlet.util

## Class PortletUtils

- java.lang.Object
- - org.springframework.web.portlet.util.PortletUtils

-     public abstract class PortletUtils
      extends Object

  Miscellaneous utilities for portlet applications. Used by various framework classes.
  Since:
    2.0
  Author:
    Juergen Hoeller, William G. Thompson, Jr., John A. Lewis

- - ### Constructor Summary

    Constructors
    Constructor and Description
    `PortletUtils()`

  - ### Method Summary

    Methods
    Modifier and Type | Method and Description
    --- | ---
    `static void` | `clearAllRenderParameters(ActionResponse response)` Clear all the render parameters from the `ActionResponse`.
    `static void` | `exposeRequestAttributes(PortletRequest request, Map<String,?> attributes)` Expose the given Map as request attributes, using the keys as attribute names and the values as corresponding attribute values.
    `static Cookie` | `getCookie(PortletRequest request, String name)` Retrieve the first cookie with the given name.
    `static <T> T` | `getNativeRequest(PortletRequest request, Class<T> requiredType)` Return an appropriate request object of the specified type, if available, unwrapping the given request as far as necessary.
    `static <T> T` | `getNativeResponse(PortletResponse response, Class<T> requiredType)` Return an appropriate response object of the specified type, if available, unwrapping the given response as far as necessary.
    `static Object` | `getOrCreateSessionAttribute(PortletSession session, String name, Class clazz)` Get the specified session attribute under the `PortletSession.PORTLET_SCOPE`, creating and setting a new attribute if no existing found.
    `static Object` | `getOrCreateSessionAttribute(PortletSession session, String name, Class clazz, int scope)` Get the specified session attribute in the given scope, creating and setting a new attribute if no existing found.
    `static Map<String,Object>` | `getParametersStartingWith(PortletRequest request, String prefix)` Return a map containing all parameters with the given prefix.
    `static String` | `getRealPath(PortletContext portletContext, String path)` Return the real path of the given path within the web application, as provided by the portlet container.
    `static Object` | `getRequiredSessionAttribute(PortletRequest request, String name)` Check the given request for a session attribute of the given name under the `PortletSession.PORTLET_SCOPE`.
    `static Object` | `getRequiredSessionAttribute(PortletRequest request, String name, int scope)` Check the given request for a session attribute of the given name in the given scope.
    `static Object` | `getSessionAttribute(PortletRequest request, String name)` Check the given request for a session attribute of the given name under the `PortletSession.PORTLET_SCOPE`.
    `static Object` | `getSessionAttribute(PortletRequest request, String name, int scope)` Check the given request for a session attribute of the given name in the given scope.
    `static Object` | `getSessionMutex(PortletSession session)` Return the best available mutex for the given session: that is, an object to synchronize on for the given session.
    `static String` | `getSubmitParameter(PortletRequest request, String name)` Return the full name of a specific input type="submit" parameter if it was sent in the request, either via a button (directly with name) or via an image (name + ".x" or name + ".y").
    `static int` | `getTargetPage(PortletRequest request, String paramPrefix, int currentPage)` Return the target page specified in the request.
    `static File` | `getTempDir(PortletContext portletContext)` Return the temporary directory for the current web application, as provided by the portlet container.
    `static boolean` | `hasSubmitParameter(PortletRequest request, String name)` Check if a specific input type="submit" parameter was sent in the request, either via a button (directly with name) or via an image (name + ".x" or name + ".y").
    `static void` | `passAllParametersToRenderPhase(ActionRequest request, ActionResponse response)` Pass all the action request parameters to the render phase by putting them into the action response object.
    `static void` | `serveResource(ResourceRequest request, ResourceResponse response, PortletContext context)` Serve the resource as specified in the given request to the given response, using the PortletContext's request dispatcher.
    `static void` | `setSessionAttribute(PortletRequest request, String name, Object value)` Set the session attribute with the given name to the given value under the `PortletSession.PORTLET_SCOPE`.
    `static void` | `setSessionAttribute(PortletRequest request, String name, Object value, int scope)` Set the session attribute with the given name to the given value in the given scope.

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

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

- - ### Constructor Detail

    - #### PortletUtils

          public PortletUtils()

  - ### Method Detail

    - #### getTempDir

          public static File getTempDir(PortletContext portletContext)

      Return the temporary directory for the current web application, as provided by the portlet container.
      Parameters:
        `portletContext` - the portlet context of the web application
      Returns:
        the File representing the temporary directory

    - #### getRealPath

          public static String getRealPath(PortletContext portletContext,
                           String path)
                                    throws FileNotFoundException

      Return the real path of the given path within the web application, as provided by the portlet container.

      Prepends a slash if the path does not already start with a slash, and throws a `FileNotFoundException` if the path cannot be resolved to a resource (in contrast to `PortletContext's {@code getRealPath}`, which simply returns `null`).

      Parameters:
        `portletContext` - the portlet context of the web application
        `path` - the relative path within the web application
      Returns:
        the corresponding real path
      Throws:
        `FileNotFoundException` - if the path cannot be resolved to a resource
      See Also:
        `PortletContext.getRealPath(java.lang.String)`

    - #### getSessionAttribute

          public static Object getSessionAttribute(PortletRequest request,
                                   String name)

      Check the given request for a session attribute of the given name under the `PortletSession.PORTLET_SCOPE`. Returns `null` if there is no session or if the session has no such attribute in that scope. Does not create a new session if none has existed before!
      Parameters:
        `request` - current portlet request
        `name` - the name of the session attribute
      Returns:
        the value of the session attribute, or `null` if not found

    - #### getSessionAttribute

          public static Object getSessionAttribute(PortletRequest request,
                                   String name,
                                   int scope)

      Check the given request for a session attribute of the given name in the given scope. Returns `null` if there is no session or if the session has no such attribute in that scope. Does not create a new session if none has existed before!
      Parameters:
        `request` - current portlet request
        `name` - the name of the session attribute
        `scope` - session scope of this attribute
      Returns:
        the value of the session attribute, or `null` if not found

    - #### getRequiredSessionAttribute

          public static Object getRequiredSessionAttribute(PortletRequest request,
                                           String name)
                                                    throws IllegalStateException

      Check the given request for a session attribute of the given name under the `PortletSession.PORTLET_SCOPE`. Throws an exception if there is no session or if the session has no such attribute in that scope.

      Does not create a new session if none has existed before!

      Parameters:
        `request` - current portlet request
        `name` - the name of the session attribute
      Returns:
        the value of the session attribute
      Throws:
        `IllegalStateException` - if the session attribute could not be found

    - #### getRequiredSessionAttribute

          public static Object getRequiredSessionAttribute(PortletRequest request,
                                           String name,
                                           int scope)
                                                    throws IllegalStateException

      Check the given request for a session attribute of the given name in the given scope. Throws an exception if there is no session or if the session has no such attribute in that scope.

      Does not create a new session if none has existed before!

      Parameters:
        `request` - current portlet request
        `name` - the name of the session attribute
        `scope` - session scope of this attribute
      Returns:
        the value of the session attribute
      Throws:
        `IllegalStateException` - if the session attribute could not be found

    - #### setSessionAttribute

          public static void setSessionAttribute(PortletRequest request,
                                 String name,
                                 Object value)

      Set the session attribute with the given name to the given value under the `PortletSession.PORTLET_SCOPE`. Removes the session attribute if value is `null`, if a session existed at all. Does not create a new session if not necessary!
      Parameters:
        `request` - current portlet request
        `name` - the name of the session attribute
        `value` - the value of the session attribute

    - #### setSessionAttribute

          public static void setSessionAttribute(PortletRequest request,
                                 String name,
                                 Object value,
                                 int scope)

      Set the session attribute with the given name to the given value in the given scope. Removes the session attribute if value is `null`, if a session existed at all. Does not create a new session if not necessary!
      Parameters:
        `request` - current portlet request
        `name` - the name of the session attribute
        `value` - the value of the session attribute
        `scope` - session scope of this attribute

    - #### getOrCreateSessionAttribute

          public static Object getOrCreateSessionAttribute(PortletSession session,
                                           String name,
                                           Class clazz)
                                                    throws IllegalArgumentException

      Get the specified session attribute under the `PortletSession.PORTLET_SCOPE`, creating and setting a new attribute if no existing found. The given class needs to have a public no-arg constructor. Useful for on-demand state objects in a web tier, like shopping carts.
      Parameters:
        `session` - current portlet session
        `name` - the name of the session attribute
        `clazz` - the class to instantiate for a new attribute
      Returns:
        the value of the session attribute, newly created if not found
      Throws:
        `IllegalArgumentException` - if the session attribute could not be instantiated

    - #### getOrCreateSessionAttribute

          public static Object getOrCreateSessionAttribute(PortletSession session,
                                           String name,
                                           Class clazz,
                                           int scope)
                                                    throws IllegalArgumentException

      Get the specified session attribute in the given scope, creating and setting a new attribute if no existing found. The given class needs to have a public no-arg constructor. Useful for on-demand state objects in a web tier, like shopping carts.
      Parameters:
        `session` - current portlet session
        `name` - the name of the session attribute
        `clazz` - the class to instantiate for a new attribute
        `scope` - the session scope of this attribute
      Returns:
        the value of the session attribute, newly created if not found
      Throws:
        `IllegalArgumentException` - if the session attribute could not be instantiated

    - #### getSessionMutex

          public static Object getSessionMutex(PortletSession session)

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

      Returns the session mutex attribute if available; usually, this means that the `HttpSessionMutexListener` needs to be defined in `web.xml`. Falls back to the `PortletSession` itself if no mutex attribute found.

      The session mutex is guaranteed to be the same object during the entire lifetime of the session, available under the key defined by the `WebUtils.SESSION_MUTEX_ATTRIBUTE` constant. It serves as a safe reference to synchronize on for locking on the current session.

      In many cases, the `PortletSession` reference itself is a safe mutex as well, since it will always be the same object reference for the same active logical session. However, this is not guaranteed across different servlet containers; the only 100% safe way is a session mutex.

      Parameters:
        `session` - the HttpSession to find a mutex for
      Returns:
        the mutex object (never `null`)
      See Also:
        `WebUtils.SESSION_MUTEX_ATTRIBUTE`, `HttpSessionMutexListener`

    - #### getNativeRequest

          public static <T> T getNativeRequest(PortletRequest request,
                               Class<T> requiredType)

      Return an appropriate request object of the specified type, if available, unwrapping the given request as far as necessary.
      Parameters:
        `request` - the portlet request to introspect
        `requiredType` - the desired type of request object
      Returns:
        the matching request object, or `null` if none of that type is available

    - #### getNativeResponse

          public static <T> T getNativeResponse(PortletResponse response,
                                Class<T> requiredType)

      Return an appropriate response object of the specified type, if available, unwrapping the given response as far as necessary.
      Parameters:
        `response` - the portlet response to introspect
        `requiredType` - the desired type of response object
      Returns:
        the matching response object, or `null` if none of that type is available

    - #### exposeRequestAttributes

          public static void exposeRequestAttributes(PortletRequest request,
                                     Map<String,?> attributes)

      Expose the given Map as request attributes, using the keys as attribute names and the values as corresponding attribute values. Keys must be Strings.
      Parameters:
        `request` - current portlet request
        `attributes` - the attributes Map

    - #### getCookie

          public static Cookie getCookie(PortletRequest request,
                         String name)

      Retrieve the first cookie with the given name. Note that multiple cookies can have the same name but different paths or domains.
      Parameters:
        `request` - current portlet request
        `name` - cookie name
      Returns:
        the first cookie with the given name, or `null` if none is found

    - #### hasSubmitParameter

          public static boolean hasSubmitParameter(PortletRequest request,
                                   String name)

      Check if a specific input type="submit" parameter was sent in the request, either via a button (directly with name) or via an image (name + ".x" or name + ".y").
      Parameters:
        `request` - current portlet request
        `name` - name of the parameter
      Returns:
        if the parameter was sent
      See Also:
        `WebUtils.SUBMIT_IMAGE_SUFFIXES`

    - #### getSubmitParameter

          public static String getSubmitParameter(PortletRequest request,
                                  String name)

      Return the full name of a specific input type="submit" parameter if it was sent in the request, either via a button (directly with name) or via an image (name + ".x" or name + ".y").
      Parameters:
        `request` - current portlet request
        `name` - name of the parameter
      Returns:
        the actual parameter name with suffix if needed - null if not present
      See Also:
        `WebUtils.SUBMIT_IMAGE_SUFFIXES`

    - #### getParametersStartingWith

          public static Map<String,Object> getParametersStartingWith(PortletRequest request,
                                                     String prefix)

      Return a map containing all parameters with the given prefix. Maps single values to String and multiple values to String array.

      For example, with a prefix of "spring_", "spring_param1" and "spring_param2" result in a Map with "param1" and "param2" as keys.

      Similar to portlet `PortletRequest.getParameterMap()`, but more flexible.

      Parameters:
        `request` - portlet request in which to look for parameters
        `prefix` - the beginning of parameter names (if this is `null` or the empty string, all parameters will match)
      Returns:
        map containing request parameters without the prefix, containing either a String or a String array as values
      See Also:
        `PortletRequest.getParameterNames()`, `PortletRequest.getParameterValues(java.lang.String)`, `PortletRequest.getParameterMap()`

    - #### getTargetPage

          public static int getTargetPage(PortletRequest request,
                          String paramPrefix,
                          int currentPage)

      Return the target page specified in the request.
      Parameters:
        `request` - current portlet request
        `paramPrefix` - the parameter prefix to check for (e.g. "_target" for parameters like "_target1" or "_target2")
        `currentPage` - the current page, to be returned as fallback if no target page specified
      Returns:
        the page specified in the request, or current page if not found

    - #### passAllParametersToRenderPhase

          public static void passAllParametersToRenderPhase(ActionRequest request,
                                            ActionResponse response)

      Pass all the action request parameters to the render phase by putting them into the action response object. This may not be called when the action will call `sendRedirect`.
      Parameters:
        `request` - the current action request
        `response` - the current action response
      See Also:
        `StateAwareResponse.setRenderParameter(java.lang.String, java.lang.String)`

    - #### clearAllRenderParameters

          public static void clearAllRenderParameters(ActionResponse response)

      Clear all the render parameters from the `ActionResponse`. This may not be called when the action will call `sendRedirect`.
      Parameters:
        `response` - the current action response
      See Also:
        `StateAwareResponse.setRenderParameters(java.util.Map<java.lang.String, java.lang.String[]>)`

    - #### serveResource

          public static void serveResource(ResourceRequest request,
                           ResourceResponse response,
                           PortletContext context)
                                    throws PortletException,
                                           IOException

      Serve the resource as specified in the given request to the given response, using the PortletContext's request dispatcher.

      This is roughly equivalent to Portlet 2.0 GenericPortlet.

      Parameters:
        `request` - the current resource request
        `response` - the current resource response
        `context` - the current Portlet's PortletContext
      Throws:
        `PortletException` - propagated from Portlet API's forward method
        `IOException` - propagated from Portlet API's forward method