PrimeFaces Ajax Poll

PrimeFaces provides <p:poll> component which is used to makes ajax calls periodically. It provides an option interval which is used to specify time.

The following example explains the usage of this component. This example contains the following files.

JSF File

// ajax-poll.xhtml

<?xml version='1.0' encoding='UTF-8' ?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN""http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml"
xmlns:h="http://xmlns.jcp.org/jsf/html"
xmlns:p="http://primefaces.org/ui">
<h:head>
<title>Ajax Poll</title>
</h:head>
<h:body>
<h:form>
<h:outputText id="poll" value="#{ajaxCounter.counter}" />
<p:poll interval="1" listener="#{ajaxCounter.increment()}" update="poll" />
</h:form>
</h:body>
</html>

ManagedBean

// AjaxCounter.java

package com.javatpoint;
import javax.faces.bean.ManagedBean;
import javax.faces.bean.ViewScoped;
@ManagedBean
@ViewScoped
public class AjaxCounter {
int counter;
public int getCounter() {
return counter;
}
public void setCounter(int counter) {
this.counter = counter;
}
public void increment(){
counter+=2;
}
}

Output:

This page updates each time on the basis of specified time. Initially, it is set to 0.