Life just got easier for users of JavaServer Faces. In a new article, now up on otn/java, titled “New JavaServer Faces 2.2 Feature: The viewAction Component,” Tom McGinn, Oracle’s Principal Curriculum Developer for Oracle Server Technologies, explores the advantages offered by the JavaServer Faces 2.2 view action feature, which, according to McGinn, “simplifies the process for performing conditional checks on initial and postback requests, enables control over which phase of the lifecycle an action is performed in, and enables both implicit and declarative navigation.”
As McGinn observes: “A view action operates like a button command (UICommand) component. By default, it is executed during the Invoke Application phase in response to an initial request. However, as you'll see, view actions can be invoked during any phase of the lifecycle and, optionally, during postback, making view actions well suited to performing preview checks.”
McGinn explains that the JavaServer Faces 2.2 view action feature offers several advantages over the previous method of performing evaluations before a page is rendered:
* View actions can be triggered early on, before a full component tree is built, resulting in a lighter weight call.
* View action timing can be controlled.
* View actions can be used in the same context as the GET request.
* View actions support both implicit and explicit navigation.
* View actions support both non-faces (initial) and faces (postback) requests.
Read the complete article here