Sending Ajax Request

RichFaces provides tag libraries which are capable to send Ajax request from JavaServer Faces pages. Following are the important tags used in the web application.

The <a4j:commandButton> and <a4j:commandLink> tags are used to send an Ajax request on the click JavaScript event.
The <a4j:poll> tag is used to send an Ajax request periodically using a timer.
The <a4j:ajax> tag allow is used to add Ajax functionality to standard JSF components and send Ajax request on a chosen JavaScript event, such as keyup or mouseover.
Most components in the r tag library have built-in Ajax support.

The <a4j:commandButton> Tag

to implement this tag we need to create the following files.

// index.xhtml

<!DOCTYPE html>
<ui:composition xmlns="http://www.w3.org/1999/xhtml" xmlns:h="http://java.sun.com/jsf/html"
xmlns:f="http://java.sun.com/jsf/core" xmlns:ui="http://java.sun.com/jsf/facelets" xmlns:a4j="http://richfaces.org/a4j"
xmlns:rich="http://richfaces.org/rich">
<h:form id="form">
<h:outputText value="User Name " />
<h:inputText value="#{user.name}" />
<a4j:commandButton value="Enter Your Name" render="out" execute="@form" />
</h:form>
<br/>
<a4j:outputPanel>
<h:outputText value="Hello #{user.name} !" rendered="#{not empty user.name}" />
</a4j:outputPanel>

</ui:composition>

// User.java

import javax.faces.bean.ManagedBean;
import javax.faces.bean.RequestScoped;
@ManagedBean
@RequestScoped
public class User {
String name;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}

// web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="3.1" xmlns="http://xmlns.jcp.org/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd">
<context-param>
<param-name>javax.faces.PROJECT_STAGE</param-name>
<param-value>Development</param-value>
</context-param>


<servlet>
<servlet-name>Faces Servlet</servlet-name>
<servlet-class>javax.faces.webapp.FacesServlet</servlet-class>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>Faces Servlet</servlet-name>
<url-pattern>/faces/*</url-pattern>
</servlet-mapping>
<session-config>
<session-timeout>
30
</session-timeout>
</session-config>
<welcome-file-list>
<welcome-file>faces/index.xhtml</welcome-file>
</welcome-file-list>
</web-app>

After running index.xhtml file, it produces the following output.

CommandLink Tag

// commandLink.xhtml

<ui:composition xmlns="http://www.w3.org/1999/xhtml" xmlns:h="http://java.sun.com/jsf/html"
xmlns:f="http://java.sun.com/jsf/core" xmlns:ui="http://java.sun.com/jsf/facelets" xmlns:a4j="http://richfaces.org/a4j"
xmlns:rich="http://richfaces.org/rich">
<h:head></h:head>
<h:form id="form">
<h:outputText value="Name: " />
<h:inputText value="#{user.name}" />
<a4j:commandLink value="Click here" render="out" execute="@form" />
</h:form>
<br />
<a4j:outputPanel id="out">
<h:outputText value="Hello #{user.name} !" />
</a4j:outputPanel>
</ui:composition>

// User.java

import javax.faces.bean.ManagedBean;
import javax.faces.bean.RequestScoped;
@ManagedBean
@RequestScoped
public class User {
String name;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}

// web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="3.1" xmlns="http://xmlns.jcp.org/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd">
<context-param>
<param-name>javax.faces.PROJECT_STAGE</param-name>
<param-value>Development</param-value>
</context-param>

<servlet>
<servlet-name>Faces Servlet</servlet-name>
<servlet-class>javax.faces.webapp.FacesServlet</servlet-class>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>Faces Servlet</servlet-name>
<url-pattern>/faces/*</url-pattern>
</servlet-mapping>
<session-config>
<session-timeout>
30
</session-timeout>
</session-config>
<welcome-file-list>
<welcome-file>faces/index.xhtml</welcome-file>
</welcome-file-list>
</web-app>

Output:

<a4j:ajax> Tag

//ajax-event.xhtml

<html xmlns="http://www.w3.org/1999/xhtml"
xmlns:h="http://xmlns.jcp.org/jsf/html"
xmlns:a4j="http://richfaces.org/a4j">
<h:head>
<title>a4j:ajax Tag</title>
</h:head>
<h:body>
<h:form>
<h:outputText value="Enter Text "></h:outputText>
<h:inputText value="#{user.name}">
<a4j:ajax event="keyup" render="user-name"></a4j:ajax>
</h:inputText>
<br/>
<br/>
<h:outputText id="user-name" value=" #{user.name}"></h:outputText>
</h:form>
</h:body>
</html>

// web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="3.1" xmlns="http://xmlns.jcp.org/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd">
<context-param>
<param-name>javax.faces.PROJECT_STAGE</param-name>
<param-value>Development</param-value>
</context-param>

<servlet>
<servlet-name>Faces Servlet</servlet-name>
<servlet-class>javax.faces.webapp.FacesServlet</servlet-class>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>Faces Servlet</servlet-name>
<url-pattern>/faces/*</url-pattern>
</servlet-mapping>
<session-config>
<session-timeout>
30
</session-timeout>
</session-config>
<welcome-file-list>
<welcome-file>faces/index.xhtml</welcome-file>
</welcome-file-list>
</web-app>

// User.java

import javax.faces.bean.ManagedBean;
import javax.faces.bean.RequestScoped;
@ManagedBean
@RequestScoped
public class User {
String name;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}

Output: