JSF - Event Handling
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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 , PreRenderViewEvent. |