JSF Under the Hood—Part 1 - JSF and HTML5 - page 50

■ You cannot use the request scope in order to keep the information after the http redirect, because the http
redirect creates a new request, which means that the current request information will be lost.

Note

Listing 2-27 shows the code of the Survey managed bean, which includes a single method save() that retrieves
the flash attributes and then prints them in the console.

Listing 2-27. The Survey Managed Bean

package com.jsfprohtml5.survey.model;

import java.io.Serializable;
import javax.faces.bean.ManagedBean;
import javax.faces.context.FacesContext;
import javax.faces.context.Flash;

@ManagedBean
public class Survey implements Serializable {
public String save() {

Flash flash = FacesContext.getCurrentInstance().getExternalContext().getFlash();

// Read the information from the flash
String userName = (String) flash.get("userName");
Number age = (Number) flash.get("age");
String sex = (String) flash.get("sex");
Number monthlyIncome = (Number) flash.get("monthlyIncome");
Number travelsAbroad = (Number) flash.get("travelsAbroad");
String travelBy = (String) flash.get("travelBy");

System.out.println("Flash information are: \n{\n" +
"Name: " + userName + ", \n" +
"Age: " + age + ", \n" +
"Sex: " + sex + ", \n" +
"monthlyIncome: " + monthlyIncome + ", \n" +
"travelsAbroad: " + travelsAbroad + ", \n" +
"travelBy: " + travelBy + "\n" +
"}");

// Save the information in the survey database ...
// ...

return "final?faces-redirect=true";
}

}

You can get the Flash object using the getFlash() API of the ExternalContext . After this, you can retrieve the
flash attributes using the get() method of the Flash object. Finally, you can do whatever you want with the retrieved
flash attributes (such as persisting them in a structured database, or using them for starting a workflow ...).