Phase Events

• Fired before and after each life cycle phase (6 × 2 = 12 events)

• Handled by phase listeners, which are classes specified in a configuration file:

       <faces-config>
          <lifecycle>
             <phase-listener>com.corejsf.PhaseTracker</phase-listener>
          </lifecycle>
       </faces-config>
  

• Phase listener classes implement the PhaseListener interface from javax.faces.event :
  • PhaseId getPhaseId(): returns which phase to listen for, e.g. PhaseId.APPLY_REQUEST_VALUES

  • void afterPhase(PhaseEvent): executed after the listened-for phase

  • void beforePhase(PhaseEvent): executed before the listened-for phase

• Phase listeners are useful for:
  • Debugging (see logging example, chapter 7)

  • Specialized uses, e.g. cross-framework apps

  • Using Ajax (chapter 11)