Java Doc for AbstractController.java in  » J2EE » spring-framework-2.0.6 » org » springframework » web » portlet » mvc » Java Source Code / Java DocumentationJava Source Code and Java Documentation

As stated in the Controller Controller interface, a lot of functionality is already provided by certain abstract base controllers. The AbstractController is one of the most important abstract base controller providing basic features such controlling if a session is required and render caching.

Workflow (and that defined by interface):

1. If this is an action request, AbstractController.handleActionRequest handleActionRequest will be called by the DispatcherPortlet once to perform the action defined by this controller.
2. If a session is required, try to get it (PortletException if not found).
3. Call method AbstractController.handleActionRequestInternal handleActionRequestInternal , (optionally synchronizing around the call on the PortletSession), which should be overridden by extending classes to provide actual functionality to perform the desired action of the controller. This will be executed only once.
4. For a straight render request, or the render phase of an action request (assuming the same controller is called for the render phase -- see tip below), AbstractController.handleRenderRequest handleRenderRequest will be called by the DispatcherPortlet repeatedly to render the display defined by this controller.
5. If a session is required, try to get it (PortletException if none found).
6. It will control caching as defined by the cacheSeconds property.
7. Call method AbstractController.handleRenderRequestInternal handleRenderRequestInternal , (optionally synchronizing around the call on the PortletSession), which should be overridden by extending classes to provide actual functionality to return org.springframework.web.portlet.ModelAndView ModelAndView objects. This will be executed repeatedly as the portal updates the current displayed page.

Exposed configuration properties (and those defined by interface):

name	default	description
requiresSession	false	whether a session should be required for requests to be able to be handled by this controller. This ensures, derived controller can - without fear of Nullpointers - call request.getSession() to retrieve a session. If no session can be found while processing the request, a PortletException will be thrown
synchronizeOnSession	false	whether the calls to handleRenderRequestInternal and handleRenderRequestInternal should be synchronized around the PortletSession, to serialize invocations from the same client. No effect if there is no PortletSession.
cacheSeconds	-1	indicates the amount of seconds to specify caching is allowed in the render response generatedby this request. 0 (zero) will indicate no caching is allowed at all, -1 (the default) will not override the portlet configuration and any positive number will cause the render response to declare the amount indicated as seconds to cache the content
renderWhenMinimized	false	whether should be rendered when the portlet is in a minimized state -- will return null for the ModelandView when the portlet is minimized and this is false

TIP: The controller mapping will be run twice by the PortletDispatcher for action requests -- once for the action phase and again for the render phase. You can reach the render phase of a different controller by simply changing the values for the criteria your mapping is using, such as portlet mode or a request parameter, during the action phase of your controller. This is very handy since redirects within the portlet are apparently impossible. Before doing this, it is usually wise to call clearAllRenderParameters and then explicitly set all the parameters that you want the new controller to see. This avoids unexpected parameters from being passed to the render phase of the second controller, such as the parameter indicating a form submit ocurred in an AbstractFormController.

Thanks to Rainer Schmitz and Nick Lothian for their suggestions!
author:
   John A. Lewis
author:
   Juergen Hoeller
since:
   2.0

More specifically, the execution of the handleActionRequestInternal method will get synchronized if this flag is "true".

The default implementation throws a PortletException.
See Also:   AbstractController.handleActionRequest
See Also:   AbstractController.handleRenderRequestInternal

The default implementation throws a PortletException.
See Also:   AbstractController.handleRenderRequest
See Also:   AbstractController.handleActionRequestInternal

More specifically, the execution of the handleActionRequestInternal method will get synchronized if this flag is "true". The best available session mutex will be used for the synchronization; ideally, this will be a mutex exposed by HttpSessionMutexListener.

The session mutex is guaranteed to be the same object during the entire lifetime of the session, available under the key defined by the 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.
See Also:   AbstractController.handleActionRequestInternal
See Also:   org.springframework.web.util.HttpSessionMutexListener
See Also:   org.springframework.web.portlet.util.PortletUtils.getSessionMutex(javax.portlet.PortletSession)