Conditional Navigation Rule in JSF 2.0

JSF 2 comes with a very flexible conditional navigation rule to solve the complex page navigation flow, see the following conditional navigation rule example :

1. JSF Page

A simple JSF page, with a button to move from this page to the payment page.

start.xhtml

##2. Managed BeanA managed bean to provide sample data to perform the conditional checking in the navigation rule.

import javax.faces.bean.ManagedBean;
import javax.faces.bean.SessionScoped;
import java.io.Serializable;

@ManagedBean
@SessionScoped
public class PaymentController implements Serializable {

private static final long serialVersionUID = 1L;public boolean registerCompleted = true;public int orderQty = 99;//getter and setter methods

}

##3. Conditional Navigation RuleNormally, you declared the simple navigation rule in the “`faces-config.xml`” like this :

start.xhtml

payment
payment.xhtml

With JSF 2, you can add some conditional checking before it move to the payment page, see following :##faces-config.xml

This is equal to the following Java code :

if (from-view-id == “start.xhtml”){

if(from-outcome == “payment”){

  if(paymentController.orderQty < 100){  return "ordermore";  }else if(paymentController.registerCompleted){  return "payment";  }else{  return "register";  }

}

}

The code should be self explanatory enough.> Note> In the conditional navigation rule, the sequence of the navigation rule does affect the navigation flow, always put the highest checking priority in the top.##4. TestingDifferent data sets for testing :###Example 1

public class PaymentController implements Serializable {

public boolean registerCompleted = true;public int orderQty = 99;...

When the button is clicked, it hits the "`paymentController.orderQty < 100`" criteria and move to the "`ordermore.xhtml`" page.###Example 2

public class PaymentController implements Serializable {

public boolean registerCompleted = true;public int orderQty = 200;...

When the button is clicked, it hits the "`paymentController.registerCompleted`" criteria and move to the "`payment.xhtml`" page.###Example 3

public class PaymentController implements Serializable {

public boolean registerCompleted = false;public int orderQty = 200;...

When the button is clicked, it failed all the checking criteria and move to the "`register.xhtml`" page.##SuggestionIn JSF 2.0, there is no "else" tag in the conditional navigation rule, wish JSF team can include the "`else`" tag in the future release. For example,

start.xhtml

payment
#{paymentController.orderQty < 100}
ordermore.xhtml
#{paymentController.registerCompleted}
payment.xhtml

register.xhtml

Moreover, It should include the multiple conditional checking as well, like this

start.xhtml

payment
#{paymentController.orderQty < 100} && #{paymentController.xxx}
ordermore.xhtml
#{paymentController.registerCompleted}
payment.xhtml

register.xhtml


“`

Thought…

JSF 2 conditional navigation rule, … quite similar with the Spring Web Flow, right? :)