This post demonstrates how to check if user is logged in before a restricted page is displayed to the user.

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Requirements

Stuff used in this post.

JSF 2.2
- javax.faces-2.2.8.jar
JDK 8

Using Event preRenderView

preRenderView is a system event that can be used to perform pre-processing before the a JSF page is displayed. For example, the following codes use preRenderView and invokes a managed bean method to perform a simple validation check.

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<!DOCTYPE html>
<html lang="en"
	xmlns="http://www.w3.org/1999/xhtml"
	xmlns:h="http://xmlns.jcp.org/jsf/html"
	xmlns:a="http://xmlns.jcp.org/jsf/facelets"	
	xmlns:f="http://xmlns.jcp.org/jsf/core">
	
	<f:metadata>
		<f:event listener="#{myBean.isLoggedIn()}" type="preRenderView"></f:event>
	</f:metadata>
	<h:head>
		<title>Demo</title>
	</h:head>
	<h:body>
		This is your dashboard! Welcome!
	</h:body>
</html>

<!DOCTYPE html>

<html lang="en"

xmlns="http://www.w3.org/1999/xhtml"

xmlns:h="http://xmlns.jcp.org/jsf/html"

xmlns:a="http://xmlns.jcp.org/jsf/facelets"

xmlns:f="http://xmlns.jcp.org/jsf/core">

<f:metadata>

<f:event listener="#{myBean.isLoggedIn()}" type="preRenderView"></f:event>

</f:metadata>

<h:head>

</h:head>

<h:body>

This is your dashboard! Welcome!

</h:body>

</html>

myBean.isLoggedIn method has these codes:

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package com.turreta.jsf.bean;

import javax.faces.application.ConfigurableNavigationHandler;
import javax.faces.bean.ManagedBean;
import javax.faces.context.FacesContext;
import javax.servlet.http.HttpSession;

@ManagedBean
public class MyBean {

	public void isLoggedIn() {
		FacesContext facesContext = FacesContext.getCurrentInstance();
		HttpSession session = (HttpSession) facesContext.getExternalContext().getSession(true);
		
		Object loggedIn = session.getAttribute("loggedIn");
		if(loggedIn == null) {
			ConfigurableNavigationHandler nav
			   = (ConfigurableNavigationHandler)
					   facesContext.getApplication().getNavigationHandler();

			nav.performNavigation("no-access");
		} else {
			// Display dashboard.xhtml
		}
	}	
}