Part Two of Deepak Vohra’s “JSF 2.0 for the Cloud” is now up on otn/java. In Part One, Vohra demonstrated how to take advantage of resource handling, @ManagedBean annotation, and implicit navigation. In Part Two, he explores new features in JSF 2.0 that make it ready for the cloud, including Ajax support, view parameters, preemptive navigation, event handling, and bookmarkable URLs.
Ajax support for JSF 2.0 components includes asynchronous transfer of data between a client and a server, along with partial page rendering, partial page processing, and grouping of components, and can be added using either f:ajax tag or the JSF Ajax library (jsf.js).
Regarding view parameters, Vohra explains, “JSF 2.0 added support for view parameters, which add the provision to send request parameters in a GET request. A view parameter is a UI component represented with the UIViewParameter class. Just like other UI components, it is saved in the UI component tree for a Facelets page and can be associated with validators and converters. A view parameter is an EditableValueHolder because it implements the interface.”
Preemptive navigation allows developers to determine the resource file that they navigate to and request parameters, if needed, based on the navigation case and view parameters, thus allowing them to create a URL for JSF resources that they access from a GET request. As a result, the URL displayed shows the resource and all request parameters.
Developers should take note that plans are in the works to update Java EE 7 for “cloud-related practical considerations, such as multitenancy and elasticity, also known as horizontal scaling.” This will be available through JSR 342, which is scheduled to complete an early draft review on May 23, 2012. Specification leads are Oracle’s Bill Shannon and Linda DeMichiel.
Access the article here.