<o:viewAction>
is a component that extends the standard <f:viewAction>
and
changes the if
attribute to be evaluated during INVOKE_APPLICATION
phase instead of the
APPLY_REQUEST_VALUES
phase. This allows developers to let the if
attribute check the
converted and validated model values before performing the view action, which results in much more intuitive behavior.
In below example, the FooConverter
may convert a non-null parameter to null
without causing
a validation or conversion error, and the intent is to redirect the current page to otherpage.xhtml
when
the converted result is null
.
<f:viewParam name="foo" value="#{bean.foo}" converter="fooConverter" /> <f:viewAction action="otherpage" if="#{bean.foo eq null}" />
This is however not possible with standard <f:viewAction>
as it evaluates the if
attribute already before the conversion has taken place. This component solves that by postponing the evaluation of
the if
attribute to the INVOKE_APPLICATION
phase.
<f:viewParam name="foo" value="#{bean.foo}" converter="fooConverter" /> <o:viewAction action="otherpage" if="#{bean.foo eq null}" />Only when you set
immediate="true"
, then it will behave the same as the standard<f:viewAction>
.
Info | Value |
---|---|
Component Type | org.omnifaces.component.input.ViewAction |
Handler Class | None |
Renderer Type | None |
Description | None |
Name | Required | Type | Description |
---|---|---|---|
action | false | javax.el.MethodExpression
(signature must match java.lang.Object action() )
|
MethodExpression representing the application action to invoke when this component is
activated by the user. The expression must evaluate to a public method that takes no parameters, and
returns an Object (the toString() of which is called to derive the logical
outcome) which is passed to the NavigationHandler for this application.
|
actionListener | false | javax.el.MethodExpression
(signature must match void actionListener(javax.faces.event.ActionEvent)
)
|
MethodExpression representing an action listener method that will be notified when this
component is activated by the user. The expression must evaluate to a public method that takes an
ActionEvent parameter, with a return type of void, or to a public method that takes no
arguments with a return type of void. In the latter case, the method has no way of easily knowing
where the event came from, but this can be useful in cases where a notification is needed that
"some action happened".
|
phase | false | javax.el.ValueExpression
(must evaluate to java.lang.String )
| Specifies the phase in which the action invocation should occur using the name of the phase constant in the PhaseId class (the case does not matter). The value must be one of APPLY_REQUEST_VALUES, PROCESS_VALIDATIONS, UPDATE_MODEL_VALUES, or INVOKE_APPLICATION. The default is INVOKE_APPLICATION. |
if | false | javax.el.ValueExpression
(must evaluate to boolean )
| Invoke the application action only when this attribute evaluates true during the specified phase. The default is true. |
onPostback | false | javax.el.ValueExpression
(must evaluate to boolean )
| View actions are most commonly used on the initial view request. Therefore, view actions do not operate on postback, by default. This attribute enables a view action to operate on postback. |
immediate | false | javax.el.ValueExpression
(must evaluate to boolean )
| Flag indicating that, if this component is activated by the user, notifications should be delivered to interested listeners and actions immediately (that is, during Apply Request Values phase) rather than waiting until Invoke Application phase. |
Output generated by Vdldoc View Declaration Language Documentation Generator.