It is quite common to display a message to the user indicating success or failure of an action. It is convenient to use a JSF FacesMessage for this. Unfortunately, a successful action often requires a browser redirect, and JSF does not propagate faces messages across redirects. This makes it quite difficult to display success messages in plain JSF.

The built in conversation-scoped Seam component named facesMessages solves this problem. (You must have the Seam redirect filter installed.)

@Name("editDocumentAction")
@Stateless
public class EditDocumentBean implements EditDocument {
    @In EntityManager em;
    @In Document document;
    @In FacesMessages facesMessages;
    
    public String update() {
        em.merge(document);
        facesMessages.add("Document updated");
    }
}

Any message added to facesMessages is used in the very next render response phase for the current conversation. This even works when there is no long-running conversation since Seam preserves even temporary conversation contexts across redirects.

You can even include JSF EL expressions in a faces message summary:

facesMessages.add("Document #{document.title} was updated");

You may display the messages in the usual way, for example:

<h:messages globalOnly="true"/>