Timer.schedule doesn't work

[Zhenya]

Hi!
I need to write an application in Java that takes a time from a
database, schedules to perform a certain action at this time and when
time comes performs this action. After this the application should
loop and take the next date from DB.
Problem is that the Timer.schedule method is working (the application
gets to entering the run() method of TimerTask), but when it comes to
performing the TimerTask it doesn't do it, it just returns to the main
application saying its queque is empty. Do you have any ideas why this
can be happening.
Below is the code:

// **************************** Main class which gets time from DB and
schedules the TimerTask to be performed ***********
package com.itisage.reminding;

import javax.ejb.Stateless;
import java.util.*;
import java.text.*;
import javax.jws.WebService;
import com.itisage.*;

@WebService(endpointInterface="com.itisage.reminding.TARemote",
portName="TAPort", serviceName="TAService", targetNamespace="http://
itisage.com/reminding/")
@Stateless

public class TA implements TARemote, TALocal

{
public void StartTA ()
{
TA.AnalyzeTime();
}

public static void AnalyzeTime ()
{
final String DATE_FORMAT = "yyyy-MM-dd HH:mm:ss";
final SimpleDateFormat dateFormat = new SimpleDateFormat
(DATE_FORMAT);
Timer timer = new Timer ();
Date RDate = null;

// Getting next reminder date
final String[] NextRemDateTime = Reminder.getNextRemDate(); // array
contains date (0) and time (1)
String NextRemDate = NextRemDateTime[0] + ' ' + NextRemDateTime[1];
try
{
RDate = dateFormat.parse(NextRemDate); // reminder date in
javaDate format
//Scheduling next job for Reminding Component
timer.schedule(new RC(), RDate);
}
catch (ParseException e)
{}
}
}

//************************************* Class that extends the
TimerTask class *********************************************
package com.itisage.reminding;

import javax.ejb.Stateless;

import com.itisage.*;
import java.util.*;

@Stateless
public class RC extends TimerTask{

public void run ()
{
RC.generateReminder();
}

public static void generateReminder ()
{
Integer RemId = Reminder.getNextRemId();
if (RemId!=0)
{
Reminder.updateDateNSent(RemId);
String RCresponse = "";
RCresponse = "Reminder # " + Integer.toString(RemId) + "
generated";
TA.AnalyzeTime();
}

else throw new RuntimeException ("No reminders to generate!");
}
}

So, the application comes to this line: RC.generateReminder();
but instead of getting into generateReminder(); goes to the end of the
main class

Please, help! What am I doing wrong? Probably you know some better way
to make a simple reminding application on java?

Best regards,
Zhenya

 

[Roedy Green]

Problem is that the Timer.schedule method is working (the application
gets to entering the run() method of TimerTask), but when it comes to
performing the TimerTask it doesn't do it,

see http://mindprod.com/jgloss/timer.html
for sample code to use it.
--
Roedy Green Canadian Mind Products
http://mindprod.com

"Patriotism is fierce as a fever, pitiless as the grave, blind as a stone, and as irrational as a headless hen."
~ Ambrose Bierce (born: 1842-06-24 died: 1914 at age: 71)

 

[markspace]

see http://mindprod.com/jgloss/timer.html
for sample code to use it.

Note the OP's example is some sort of web service or EJB component. I
think there are special requirements that your desktop oriented link
doesn't cover.

Quoting the OP:

 

[Arne Vajhøj]

I need to write an application in Java that takes a time from a
database, schedules to perform a certain action at this time and when
time comes performs this action. After this the application should
loop and take the next date from DB.
Problem is that the Timer.schedule method is working (the application
gets to entering the run() method of TimerTask), but when it comes to
performing the TimerTask it doesn't do it, it just returns to the main
application saying its queque is empty. Do you have any ideas why this
can be happening.
Below is the code:

// **************************** Main class which gets time from DB and
schedules the TimerTask to be performed ***********
package com.itisage.reminding;

import javax.ejb.Stateless;
import java.util.*;
import java.text.*;
import javax.jws.WebService;
import com.itisage.*;

@WebService(endpointInterface="com.itisage.reminding.TARemote",
portName="TAPort", serviceName="TAService", targetNamespace="http://
itisage.com/reminding/")
@Stateless

public class TA implements TARemote, TALocal

{
public void StartTA ()
{
TA.AnalyzeTime();
}

public static void AnalyzeTime ()
{
final String DATE_FORMAT = "yyyy-MM-dd HH:mm:ss";
final SimpleDateFormat dateFormat = new SimpleDateFormat
(DATE_FORMAT);
Timer timer = new Timer ();
Date RDate = null;

// Getting next reminder date
final String[] NextRemDateTime = Reminder.getNextRemDate(); // array
contains date (0) and time (1)
String NextRemDate = NextRemDateTime[0] + ' ' + NextRemDateTime[1];
try
{
RDate = dateFormat.parse(NextRemDate); // reminder date in
javaDate format
//Scheduling next job for Reminding Component
timer.schedule(new RC(), RDate);
}
catch (ParseException e)
{}
}
}

//************************************* Class that extends the
TimerTask class *********************************************
package com.itisage.reminding;

import javax.ejb.Stateless;

import com.itisage.*;
import java.util.*;

@Stateless
public class RC extends TimerTask{

public void run ()
{
RC.generateReminder();
}

public static void generateReminder ()
{
Integer RemId = Reminder.getNextRemId();
if (RemId!=0)
{
Reminder.updateDateNSent(RemId);
String RCresponse = "";
RCresponse = "Reminder # " + Integer.toString(RemId) + "
generated";
TA.AnalyzeTime();
}

else throw new RuntimeException ("No reminders to generate!");
}
}

So, the application comes to this line: RC.generateReminder();
but instead of getting into generateReminder(); goes to the end of the
main class

Please, help! What am I doing wrong? Probably you know some better way
to make a simple reminding application on java?

It is impossible to troubleshoot exactly what is going wrong based
on the available information.

But you are definitely on the wrong track.

EJB's are not allowed to start threads (and a timer is a thread).

You should use the timer service build into the app server
(since EJB 2.1).

Arne

 

[Zhenya]

I need to write an application in Java that takes a time from a
database, schedules to perform a certain action at this time and when
time comes performs this action. After this the application should
loop and take the next date from DB.
Problem is that the Timer.schedule method is working (the application
gets to entering the run() method of TimerTask), but when it comes to
performing the TimerTask it doesn't do it, it just returns to the main
application saying its queque is empty. Do you have any ideas why this
can be happening.
Below is the code:

// **************************** Main class which gets time from DB and
schedules the TimerTask to be performed ***********
package com.itisage.reminding;

import javax.ejb.Stateless;
import java.util.*;
import java.text.*;
import javax.jws.WebService;
import com.itisage.*;

@WebService(endpointInterface="com.itisage.reminding.TARemote",
portName="TAPort", serviceName="TAService", targetNamespace="http://
itisage.com/reminding/")
@Stateless

public class TA implements TARemote, TALocal

{
   public void StartTA ()
   {
           TA.AnalyzeTime();
   }

   public static void AnalyzeTime ()
   {
           final String DATE_FORMAT = "yyyy-MM-dd HH:mm:ss";
           final SimpleDateFormat dateFormat = new SimpleDateFormat
(DATE_FORMAT);
           Timer timer     = new Timer ();
           Date RDate = null;

           // Getting next reminder date
           final String[] NextRemDateTime = Reminder.getNextRemDate(); // array
contains date (0) and time (1)
           String NextRemDate = NextRemDateTime[0] + ' ' + NextRemDateTime[1];
           try
                   {
                           RDate = dateFormat.parse(NextRemDate); // reminder date in
javaDate format
                           //Scheduling next job for Reminding Component
                           timer.schedule(new RC(), RDate);
                   }
           catch (ParseException e)
                   {}
   }
}

//************************************* Class that extends the
TimerTask class *********************************************
package com.itisage.reminding;

import javax.ejb.Stateless;

import com.itisage.*;
import java.util.*;

@Stateless
public class RC extends TimerTask{

   public void run ()
   {
           RC.generateReminder();
   }

   public static void generateReminder ()
   {
           Integer RemId = Reminder.getNextRemId();
           if (RemId!=0)
                   {
                   Reminder.updateDateNSent(RemId);
                   String RCresponse = "";
                   RCresponse = "Reminder # " + Integer.toString(RemId) + "
generated";
                   TA.AnalyzeTime();
                   }

           else throw new RuntimeException ("No reminders to generate!");
   }
}

So, the application comes to this line: RC.generateReminder();
but instead of getting into generateReminder(); goes to the end of the
main class

Please, help! What am I doing wrong? Probably you know some better way
to make a simple reminding application on java?

It is impossible to troubleshoot exactly what is going wrong based
on the available information.

But you are definitely on the wrong track.

EJB's are not allowed to start threads (and a timer is a thread).

You should use the timer service build into the app server
(since EJB 2.1).

Arne

Thanks for the tip on Timer service, I'll digg into this, hope that'll
work. I'm a complete newbie in Java and in EJB also, just need to code
this scheduling application as part of my project..
Thanks again for your help!

Zhenya

 

[Arne Vajhøj]

I need to write an application in Java that takes a time from a
database, schedules to perform a certain action at this time and when
time comes performs this action. After this the application should
loop and take the next date from DB.
Problem is that the Timer.schedule method is working (the application
gets to entering the run() method of TimerTask), but when it comes to
performing the TimerTask it doesn't do it, it just returns to the main
application saying its queque is empty. Do you have any ideas why this
can be happening.
Below is the code:
// **************************** Main class which gets time from DB and
schedules the TimerTask to be performed ***********
package com.itisage.reminding;
import javax.ejb.Stateless;
import java.util.*;
import java.text.*;
import javax.jws.WebService;
import com.itisage.*;
@WebService(endpointInterface="com.itisage.reminding.TARemote",
portName="TAPort", serviceName="TAService", targetNamespace="http://
itisage.com/reminding/")
@Stateless
public class TA implements TARemote, TALocal
{
public void StartTA ()
{
TA.AnalyzeTime();
}
public static void AnalyzeTime ()
{
final String DATE_FORMAT = "yyyy-MM-dd HH:mm:ss";
final SimpleDateFormat dateFormat = new SimpleDateFormat
(DATE_FORMAT);
Timer timer = new Timer ();
Date RDate = null;
// Getting next reminder date
final String[] NextRemDateTime = Reminder.getNextRemDate(); // array
contains date (0) and time (1)
String NextRemDate = NextRemDateTime[0] + ' ' + NextRemDateTime[1];
try
{
RDate = dateFormat.parse(NextRemDate); // reminder date in
javaDate format
//Scheduling next job for Reminding Component
timer.schedule(new RC(), RDate);
}
catch (ParseException e)
{}
}
}
//************************************* Class that extends the
TimerTask class *********************************************
package com.itisage.reminding;
import javax.ejb.Stateless;
import com.itisage.*;
import java.util.*;
@Stateless
public class RC extends TimerTask{
public void run ()
{
RC.generateReminder();
}
public static void generateReminder ()
{
Integer RemId = Reminder.getNextRemId();
if (RemId!=0)
{
Reminder.updateDateNSent(RemId);
String RCresponse = "";
RCresponse = "Reminder # " + Integer.toString(RemId) + "
generated";
TA.AnalyzeTime();
}
else throw new RuntimeException ("No reminders to generate!");
}
}
So, the application comes to this line: RC.generateReminder();
but instead of getting into generateReminder(); goes to the end of the
main class
Please, help! What am I doing wrong? Probably you know some better way
to make a simple reminding application on java?

It is impossible to troubleshoot exactly what is going wrong based
on the available information.

But you are definitely on the wrong track.

EJB's are not allowed to start threads (and a timer is a thread).

You should use the timer service build into the app server
(since EJB 2.1).

Thanks for the tip on Timer service, I'll digg into this, hope that'll
work. I'm a complete newbie in Java and in EJB also, just need to code
this scheduling application as part of my project..
Thanks again for your help!

The relevant section of the Java EE tutorial is:
http://java.sun.com/javaee/5/docs/tutorial/doc/bnboy.html

But the tutorial is not very good for this.

Chapter 12 in this:
http://www.theserverside.com/tt/books/wiley/masteringEJB3/index.tss
is a little bit better.

Arne