JSF - Event Handling

JSF Event Handling

• When a user clicks a JSF button or link or changes any value in text field, JSF UI component fires event which will be handled by the the application code.
• To handle such event, event handler are to be registered in the application code or managed bean.
• When a UI component checks that a user event has happened, it creates an instance of the corresponding event class and adds it to an event list.
  
• Then, Component fires the event, i.e., checks the list of listeners for that event and call the event notification method on each listener or handler.
• JSF also provide system level event handlers which can be used to do some tasks when application starts or is stopping.

Following are important Event Handler in JSF 2.0:

S.N.	Event Handlers & Description
1	valueChangeListener Value change events get fired when user make changes in input components.
2	actionListener Action events get fired when user clicks on a button or link component.
3	Application Events Events firing during JSF lifecycle: PostConstructApplicationEvent, PreDestroyApplicationEvent , PreRenderViewEve