How to emulate request scope behavior in session scope bean?

In my jsf application I have a button for sending mail. And each time it clicked I want to show message that mail was or wasn't sent.

This is a typical request-scope functionality. But the problem is that I have 1 backing bean with session scope now. And all data is in this bean. And method 'send' referred by action attribute开发者_C百科 of the button is in this bean.

So, what is the way out? If I should create one more request-scope bean then how should I refer to it from my session bean?

Another approach, you can make use of FacesMessage here which you add to the context using FacesContext#addMessage(). FacesMessages are request based and likely more suited for the particular functional requirement than some custom messaging approach.

Here's an example of the bean action method:

public void sendMail() {
    FacesMessage message;
    try {
        Mailer.send(from, to, subject, message);
        message = new FacesMessage("Mail successfully sent!");
    } catch (MailException e) {
        message = new FacesMessage("Sending mail failed!");
        logger.error("Sending mail failed!", e); // Yes, you need to know about it as well! ;)
    }
    FacesContext.getCurrentInstance().addMessage(null, message);
}

With a null clientId the message becomes "global", so that you can make use of the following construct to display only global messages:

 <h:messages globalOnly="true" />

Update: to have the success and error message displayed in a different style, play with the FacesMessage.Severity:

        message = new FacesMessage(FacesMessage.SEVERITY_INFO, "Mail successfully sent!", null);
    } catch (MailException e) {
        message = new FacesMessage(FacesMessage.SEVERITY_ERROR, "Sending mail failed!", null);

.. in combination with infoClass/infoStyle and errorClass/errorStyle in h:messages:

 <h:messages globalOnly="true" infoStyle="color:green" errorStyle="color:red" />

Either:

• just push the message onto the request scope from the send method (via the ExternalContext)
• refactor the method to a request-scope bean and inject any session information it needs (the managed bean framework can do this)