[OmniFaces utilities 2.0] Add in flash scope a parameterized global (or to the given client ID) ERROR faces message

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[OmniFaces utilities] The addFlashError() method adds a flash scoped ERROR faces message to the given clientId, with the given message body which is formatted with the given parameters. Use this when you need to display the message after a redirect.

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Method:

See also: Faces#getContext() | Faces#getFlash()

Usage:

The information stored in flash scope "survives" one redirect. Let's suppose that the below code is in page A.xhtml:

<h:form>

 <h:commandButton value="Click Me!" action="#{myBean.myAction()}"/>

</h:form>

The myAction() method perform some tasks, including generating a global ERROR parameterized messages and redirecting to page, B.xhtml:

import org.omnifaces.util.Messages;

...

// ERROR message

private static final String FILES_UPLOADED_ERROR = "The {0} file cannot be uploaded ! File size should be smaller than {1} bytes.";

...

// for a certain component, replace null with clientId

public String myAction() {

// add an ERROR message as a global message in flash scope

Object[] params = new Object[]{"order.txt", 1024};

Messages.addFlashError(null, FILES_UPLOADED_ERROR, "order.txt", 1024);

// or

Messages.addFlashError(null, FILES_UPLOADED_ERROR, params);

return "B?faces-redirect=true";

}

Now, in page B.xhtml, you will see this message:

// ERROR message

The order.txt file cannot be uploaded ! File size should be smaller than 1,024 bytes.

Note Don't forget to use in page where the messages are displayed the <h:messages>, for global messages, <h:message>, for component messages, or any other approach capable to display the messages.

Note By default, this example uses the OmniFaces default message resolver, but you can use your own message resolver as in Working with OmniFaces Message Resolvers.

API GH