Scheduler In Liferay

                             

Sometimes  it requires to execute some backend code on regular interval or at some specific time.

For example : wants to send mail to user on regular interval  or at specific time.

Liferay has provided feature of  scheduler for achieving this kind of requirement.

For scheduling we are using two types of trigger:

1. Simple Trigger (when ever scheduling requirement is based on regular interval basis, will use simple trigger)

2. Cron Trigger  (Whenever scheduling requirement is based on some specific time, will use cron  trigger)

Simple Trigger Scheduler  Steps

Step 1: Create one liferay project of portlet plugin type, in our example project name is Scheduler,    (suffix portlet will automatically added after project name) so after creation project complete name will be Scheduler-portlet

Inside that Scheduler-portlet project create one portlet , in our example portlet class name is Schedule.

Step 2: Create one class name SimpleTrigger     inside docroot/web-inf-src/com/test/ , after class creation complete path will be  docroot/web-inf-src/com/test/SimpleTrigger

This simpleTrigger class  will implements  MessageListener

 Below is the complete code of  SimpleTrigger class.

package com.test;

import com.liferay.portal.kernel.messaging.Message;

import com.liferay.portal.kernel.messaging.MessageListener;

import com.liferay.portal.kernel.messaging.MessageListenerException;

public class SimpleTrigger implements MessageListener  {

       public void receive(Message arg0) throws MessageListenerException {

            //any logic whatever you want to execute, you can write here.

              System.out.println("simple trigger scheduler example...");

       }

}

Step 3: Paste below code in portlet view.jsp

<%@ taglib uri="http://java.sun.com/portlet_2_0" prefix="portlet" %>

<portlet:defineObjects />

<p style="border:1px solid green;">Liferay Scheduler</p>

<p>Simple Trigger Scheduler, Trigger every 1 min interval</p>

Step 4: In liferay-portlet.xml define scheduler entry like below

<?xml version="1.0"?>

<!DOCTYPE liferay-portlet-app PUBLIC "-//Liferay//DTD Portlet Application 6.2.0//EN" "http://www.liferay.com/dtd/liferay-portlet-app_6_2_0.dtd">

<liferay-portlet-app>

      

       <portlet>

              <portlet-name>schedule</portlet-name>

              <icon>/icon.png</icon>

              <scheduler-entry> 

             <scheduler-event-listener-class>com.test.SimpleTrigger</scheduler-event-listener-class> 

             <trigger> 

               <simple> 

                  <simple-trigger-value>1</simple-trigger-value>  

                  <time-unit>minute</time-unit>   

               </simple> 

             </trigger> 

        </scheduler-entry> 

              <header-portlet-css>/css/main.css</header-portlet-css>

              <footer-portlet-javascript>

                     /js/main.js

              </footer-portlet-javascript>

              <css-class-wrapper>schedule-portlet</css-class-wrapper>

       </portlet>

       <role-mapper>

              <role-name>administrator</role-name>

              <role-link>Administrator</role-link>

       </role-mapper>

       <role-mapper>

              <role-name>guest</role-name>

              <role-link>Guest</role-link>

       </role-mapper>

       <role-mapper>

              <role-name>power-user</role-name>

              <role-link>Power User</role-link>

       </role-mapper>

       <role-mapper>

              <role-name>user</role-name>

              <role-link>User</role-link>

       </role-mapper>

</liferay-portlet-app>

*In above scheduler entry we have used

<scheduler-event-listener-class>com.test.SimpleTrigger</scheduler-event-listener-class>

for defining  scheduler event listener class path.

<trigger></trigger>

using trigger tag we have defined which trigger we are going to use simple/cron, in this example we are using simple trigger.

in <time-unit> tag we can give hour,day,week value also.

*In this simple trigger example , for every 1 min of regular interval code written inside receive method will execute.

Output : 

Cron Trigger Scheduler Steps

sometime, we may need that scheduler job  run  at specific time [say 11 :20PM, each tuesday ] job should run. Trigger specified in above code(simple trigger) will not work in that case. For this type of requirement we can specify cron trigger.

Step 1: Create one liferay project of portlet plugin type, in our example project name is Scheduler,    (suffix portlet will automatically added after project name) so after creation project complete name will be Scheduler-portlet

Inside that Scheduler-portlet project create one portlet , in our example portlet class name is Schedule.

Step 2: 
 <%@ taglib uri="http://java.sun.com/portlet_2_0" prefix="portlet" %>

<portlet:defineObjects />

<p style="border:1px solid green;">Liferay Scheduler</p>
<p>Cron Trigger Scheduler, Trigger every year,every month,every day,every hour, every minute on 10's second</p>

Step 3: Create one new class name CronTrigger     inside docroot/web-inf-src/com/test/ , after class creation complete path will be  docroot/web-inf-src/com/test/CronTrigger

This CronTrigger class  will implements  MessageListener
 

 Below is the complete code of  CronTrigger class.

package com.test;

import com.liferay.portal.kernel.messaging.Message;
import com.liferay.portal.kernel.messaging.MessageListener;
import com.liferay.portal.kernel.messaging.MessageListenerException;

public class CronTrigger implements MessageListener  {

   
    public void receive(Message arg0) throws MessageListenerException {
       
        System.out.println("Cron trigger scheduler example...");
       
    }

}

Step 4: Define  scheduler entry  for cron trigger in liferay-portlet.xml

<trigger> 
              <cron> 
                 <cron-trigger-value>10 * * ? * * *</cron-trigger-value> 
              </cron>
 </trigger>

[above cron text specify : every year,every month,every day,every hour, every minute on 10's second]


 MIN  HOUR  DAYOFMONTH  MONTH  DAYOFWEEK  YEAR

Some Example Cron-text:

"0 0 12 * * ? *"                    Fire at 12pm (noon) every day
"0 15 10 ? * * *"                  Fire at 10:15am every day
"0 10,44 14 ? 3 WED *"     Fire at 2:10pm and at 2:44pm every Wednesday in the month of March.
"0 15 10 ? * MON-FRI *"  Fire at 10:15am every Monday, Tuesday, Wednesday, Thursday and Friday

 



complete liferay-portlet.xml code:

<?xml version="1.0"?>
<!DOCTYPE liferay-portlet-app PUBLIC "-//Liferay//DTD Portlet Application 6.2.0//EN" "http://www.liferay.com/dtd/liferay-portlet-app_6_2_0.dtd">

<liferay-portlet-app>
   
    <portlet>
        <portlet-name>schedule</portlet-name>
        <icon>/icon.png</icon>
        <scheduler-entry>
             <scheduler-event-listener-class>com.test.CronTrigger</scheduler-event-listener-class> 
             <trigger> 
              <cron> 
                 <cron-trigger-value>50 * * ? * * *</cron-trigger-value> 
              </cron> 
            </trigger>
        </scheduler-entry> 
        <header-portlet-css>/css/main.css</header-portlet-css>
        <footer-portlet-javascript>
            /js/main.js
        </footer-portlet-javascript>
        <css-class-wrapper>schedule-portlet</css-class-wrapper>
    </portlet>
    <role-mapper>
        <role-name>administrator</role-name>
        <role-link>Administrator</role-link>
    </role-mapper>
    <role-mapper>
        <role-name>guest</role-name>
        <role-link>Guest</role-link>
    </role-mapper>
    <role-mapper>
        <role-name>power-user</role-name>
        <role-link>Power User</role-link>
    </role-mapper>
    <role-mapper>
        <role-name>user</role-name>
        <role-link>User</role-link>
    </role-mapper>
</liferay-portlet-app>

Output :