viewAction (OmniFaces 5.3 VDL Documentation)

Description:
The <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>.
Usage

You can use it the same way as <f:viewAction>, you only need to change f: to o:.
```
 <o:viewAction action="otherpage" if="#{bean.property eq null}" />
 
```
Messaging

You can use the message attribute to add a global flash warning message.
```
 <o:viewAction ... message="Please use a valid link from within the site" />
 
```
Note that the message will only be shown when the redirect has actually taken place. The support was added in OmniFaces 3.2.

Component Information
Info	Value
Component Type	`org.omnifaces.component.input.ViewAction`
Handler Class	None
Renderer Type	None
Description	None

Attributes
Name	Required	Type	Description
`action`	`false`	`jakarta.el.MethodExpression` (signature must match `java.lang.Object action()`)	MethodExpression representing the application action to invoke when this component is activated. The expression must evaluate to a public method that takes no parameters, and returns an Object (the logical outcome) which is passed to the NavigationHandler for this application.
`actionListener`	`false`	`jakarta.el.MethodExpression` (signature must match `void processAction(jakarta.faces.event.ActionEvent)`)	MethodExpression representing an action listener method that will be notified when this component is activated. The expression must evaluate to a public method that takes an ActionEvent parameter, with a return type of void.
`binding`	`false`	`jakarta.el.ValueExpression` (must evaluate to `jakarta.faces.component.UIComponent`)	The ValueExpression linking this component to a property in a backing bean.
`id`	`false`	`jakarta.el.ValueExpression` (must evaluate to `java.lang.String`)	The component identifier for this component. This value must be unique within the closest parent component that is a naming container.
`if`	`false`	`jakarta.el.ValueExpression` (must evaluate to `boolean`)	Invoke the application action only when this attribute evaluates true during the specified phase. The default is true.
`immediate`	`false`	`jakarta.el.ValueExpression` (must evaluate to `boolean`)	No Description
`message`	`false`	`jakarta.el.ValueExpression` (must evaluate to `java.lang.String`)	The global flash warning message to be shown in the redirected page.
`onPostback`	`false`	`jakarta.el.ValueExpression` (must evaluate to `boolean`)	No Description
`phase`	`false`	`jakarta.el.ValueExpression` (must evaluate to `java.lang.String`)	No Description
`rendered`	`false`	`jakarta.el.ValueExpression` (must evaluate to `boolean`)	Flag indicating whether or not this component should be rendered (during Render Response Phase), or processed on any subsequent form submit. The default value for this property is true.

o

Tag viewAction

Usage

Messaging