o

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>.
                    
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.