Creating a schedular in Liferay

This post will explain how to create a " Schedular " in Lifeay .
Mainly we create a schedular to perform a particular Task in Particular Time without any Action.
eg: we need trigger a mails daily at particular time or we need to trigger for every 12 hours.

Step 1:
 First you want to create a class ( Which is nothing bur your own schedular class) in your portlet inside the "src" folder.
     ex : i created the schedular class in src folder in the path "com.portal.product.scheduler.Scheduler"

Step 2:
Next you want to create a "schedular entry" to that particular portlet inside the liferay-portlet.xml

<liferay-portlet-app>
      <portlet>
            <portlet-name>product</portlet-name>
            <icon>/icon.png</icon>
            <scheduler-entry>
                   <scheduler-event-listener-class>com.portal.product.scheduler.Scheduler</scheduler-event-listener-class>// path of the schedular class which  u created in the first step
                    <trigger>
                               <simple>
<simple-trigger-value>12</simple-trigger-value>
<time-unit>hour</time-unit>
</simple>
                                <cron>
                                        <cron-trigger-value>  0 0 8 * * ? * </cron-trigger-value>
                                </cron>
                  </trigger>
            </scheduler-entry>
      </portlet>
</liferay-portlet-app>

Note: Either you want use  <simple>( to run for every 12 hours)  or  <cron> ( to run in particular ). here i am running the schedular on every day 8'o clock . To know detail about <cron> ( http://www.quartz-scheduler.org/documentation/quartz-1.x/tutorials/crontrigger    ,  http://www.cronmaker.com/  )

Step 3:  U have to write the Business Logic inside the schedular class

Scheduler.java

package com.portal.product.scheduler;

public class Scheduler implements MessageListener{

                public void receive(Message message) throws MessageListenerException {
              
                   // here u want to write the business logic based upon your requirement
                        dailyMail(); 
                }
               private void dailyMail() throws SystemException {
MailUtil.senddailyEmail();

}
}