February 21 2013 Thursday

DOTS Deep Dive 4: I can schedule myself...

Finally, we will be able to enable FeedMonster for CollaborationToday project.

While doing final touches, I have been challenged by a question: "Can we schedule DOTS tasklets programmatically?"

Actually, this is in the wish list for the next version of DOTS. But we can do some trick here. I didn't test this on Domino 9 but it should work.

Here is the code:

package org.openntf.news.playground.tasklets; 

import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IProgressMonitor;

import com.ibm.dots.annotation.RunOnStart;
import com.ibm.dots.task.AbstractServerTaskExt;
import com.ibm.dots.task.RunWhen;
import com.ibm.dots.task.RunWhen.RunUnit;
import com.ibm.dots.task.ServerTaskManager;

public class CustomSchedule extends AbstractServerTaskExt {

       @Override
       public void dispose() {

       }
       
       @RunOnStart
       public void scheduleMe(IProgressMonitor monitor) {
               ServerTaskManager stm=ServerTaskManager.getInstance();
               
               // Every 10 seconds
               RunWhen sched=new RunWhen(RunUnit.second, 10, 0, 0);
               
               try {
                       // custom01 is this tasklet's id as defined in plugin.xml
                       stm.scheduleTasklet("custom01", sched);
               } catch (CoreException e) {
                       e.printStackTrace();
               }
               
               logMessage("I have scheduled myself for "+sched);
               
       }
       
       @Override
       protected void doRun(RunWhen runWhen, IProgressMonitor monitor) {
               logMessage("CustomSchedule: "+runWhen.toString());
       }
       
}


So it's simple. There is a ServerTaskManager singleton object which manages all tasklets. We are using ".schedule(...)" method (luckily it's public).

When we load DOTS:

> load dots 
Listening for transport dt_socket at address: 8001
21.02.2013 13:55:30   Domino OSGi Tasklet Container started ( profile DOTS )
21.02.2013 13:55:31   [DOTS] (custom01) I have scheduled myself for Runs every 10 - second
21.02.2013 13:55:33   [DOTS] (custom01) CustomSchedule: Runs every 10 - second
21.02.2013 13:55:43   [DOTS] (custom01) CustomSchedule: Runs every 10 - second


You can use some kind of parameterization to customize your tasklet scheduling. For instance, I am planning to use this functionality for FeedMonster such that If there are only 5 feeds to be read, it's useless to receive new stories every 5 minutes. However, there is no way to 'unschedule' a tasklet. We'll find another trick for this.

ServerTaskManager is a great object BTW. For instance;

stm.runTasklet("someTasklet", "argument1", "argument2");


I didn't find it safe though. Since it doesn't submit a CommandInterpreter object, there might be a problem in error trapping. Noted to the list of feedbacks :)
Serdar Basegmez   |   February 21 2013 03:05:00 PM   |    DOTS  XPages    |  
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