The immediate Attribute

Input components and command components (those that implement the ActionSource interface, such as buttons and hyperlinks) can set the immediate attribute to true to force events, validations, and conversions to be processed when request parameter values are applied.

You need to carefully consider how the combination of an input component’s immediate value and a command component’s immediate value determines what happens when the command component is activated.

Assume that you have a page with a button and a field for entering the quantity of a book in a shopping cart. If the immediate attributes of both the button and the field are set to true, the new value entered in the field will be available for any processing associated with the event that is generated when the button is clicked. The event associated with the button as well as the event validation and conversion associated with the field are all handled when request parameter values are applied.

If the button’s immediate attribute is set to true but the field’s immediate attribute is set to false, the event associated with the button is processed without updating the field’s local value to the model layer. The reason is that any events, conversion, or validation associated with the field occurs after request parameter values are applied.