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The following page has been changed by SimonKitching: http://wiki.apache.org/shale/ShaleViewController The comment on the change is: Add details about ViewController not in main docs New page: == Overview == The Shale `ViewController` functionality allows a managed bean to get callbacks on a per-view (ie per-page) basis, in contrast to the normal callbacks invoked per-component. == Configuration == The jsf configuration files included in the shale-core jarfiles automatically registers the necessary shale objects with the JSF implementation, so no changes need to be made to web.xml; just placing the shale jarfile in the webapp's WEB-INF/lib directory is sufficient. The `ViewViewHandler` class implements the JSF standard `ViewHandler` class. It is installed as a wrapper around the `ViewHandler` implementation provided by the underlying JSF implementation. It is this class that invokes the setPostBack method on the `ViewController`. In order to tell shale's view controller framework which bean to call for each page, it is necessary to define a `ViewControllerMapper` strategy which creates a managed bean name from the value returned by `UIViewRoot.getViewId()`, ie from the portion of the page url between the webapp name and the query params. An instance of `DefaultViewControllerMapper` is used by default; see the documentation for that class for details of the mapping. The managed bean with that name is expected to implement the `ViewController` interface (but see comments on Tiger below). It is possible to override the default `ViewControllerMapper` simply by defining an application-scoped managed bean with name "org$apache$shale$view$VIEW_MAPPER" that implements the `ViewControllerMapper` interface. == Subviews == In the Shale 1.0.3 release (latest at the current date) there is no support for callbacks for subviews. This means that even if a page is composed of multiple other pages (via jsp:include or other mechanism), all page-related callbacks must go through a single managed bean which introduces undesirable coupling. The trunk code as at 2006-11-07 contains some code that appears to support a separate ViewController managed bean for each f:subview in the page by overriding the renderer for subviews to invoke preprocess on processDecodes and prerender on encodeBegin. == Tiger == If the Shale Tiger libraries are present, then a few more features are available. Tiger is specifically for java 1.5 and allows the use of annotations on ordinary managed beans to mark the view-controller callback methods rather than requiring the managed bean to implement the `ViewController` interface. == Implementation Classes == * `org.apache.shale.view.faces.ViewController` defines the callbacks available; the managed bean needs to implement this interface in order to get callbacks. Alternately, concrete subclass `AbstractViewController` can be subclassed. * `org.apache.shale.view.faces.LifecycleListener` invokes the init and destroy callbacks. * `ViewViewHandler` wraps the standard `ViewHandler` and whenever a view is created (eg restore or forward) it determines which managed bean corresponds to this view and caches this in the current request. * `ViewPhaseListener` invokes the preprocess/prerender methods on the `ViewController` managed bean located earlier by the `ViewViewHandler`.
