Learn Java for Web Development

278 CHAPTER 6: Component-Based Web Development Using JSF 2

Phase 1: Restore View

JSF begins the Restore View phase as soon as a link or button is clicked and JSF receives a request.
During this phase, JSF does the following:

   Builds a component tree from the page. This component tree contains the

information associated with all components of the page. If the page is requested

for the first time, JSF creates an empty view.

   Wires event handlers and validators to UI components.

   Saves the view in the FacesContext instance.

Phase 2: Apply Request Values

After the component tree is created/restored, the JSF runtime runs the decode method of each
component in the component tree that extracts the values from the request parameters. The values
that are extracted by the decode method are stored in the component, after performing data conversion
if necessary. If the conversion fails, an error message is generated and queued on FacesContext.

Phase 3: Process Validation

During this phase, the JSF runtime processes validators registered on the component tree during the
Restore View phase. If there are validation errors, JSF adds an error message to the FacesContext
instance, skips the fourth and fifth phases, enters the Render Response phase, and displays the
error messages.

Phase 4: Update Model

If there are no validation errors in the Process Validation phase, the JSF runtime updates the
managed bean’s properties that are bound to the UI components with the new values of the UI
components. The conversion is also performed in this phase if necessary.

Request

Render response

on First request

Response

Restore View

Render

Response

Invoke

Application

Apply Request

Value

Update Model

Process

Validation

Figure 6-14. The phases of the JSF life cycle