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Generating Cron Expression

Gnana Prasuna
Greenhorn

Joined: Feb 18, 2009
Posts: 14
Hi All,

I need to build cron Expression for the below occurences. Can some body help me on this.
The occurence is:

1.)fire event at 12:30 start at 18/2/2009 and end by 25/2/2010.
2.) fire event between 12:15 and 13:45 start at 18/2/2009 and end by 25/2/2010.


Thanks,
Prasuna
Sagar Rohankar
Ranch Hand

Joined: Feb 19, 2008
Posts: 2902
    
    1

Gnana Prasuna wrote:
I need to build cron Expression for the below occurences. Can some body help me on this.
The occurence is:

1.)fire event at 12:30 start at 18/2/2009 and end by 25/2/2010.
2.) fire event between 12:15 and 13:45 start at 18/2/2009 and end by 25/2/2010.


Have you tried to write some expression, We are ready to help you If you show some efforts first.

Here is the tutorial link, that help you to understand basic CronnTrigger expression, starts with the simplest one then tried out some complicated crons.

And welcome to JavaRanch !


[LEARNING bLOG] | [Freelance Web Designer] | [and "Rohan" is part of my surname]
Gnana Prasuna
Greenhorn

Joined: Feb 18, 2009
Posts: 14
Hi,

I am able to generate simple cron expressions. But i need help on generating craon expression between stat date and end date as mentioned above.

Thanks,
Prasuna
Sagar Rohankar
Ranch Hand

Joined: Feb 19, 2008
Posts: 2902
    
    1

Ok.. Lets have some hints for you to build a cron expression..
In the give tutorial I mentioned in the previous post, it says that, we have two "special character" , which is used to mention a range, like for year 2009, 2010, etc ..
particularly, the statements are

* - - used to specify ranges. For example, "10-12" in the hour field means "the hours 10, 11 and 12".

* , - used to specify additional values. For example, "MON,WED,FRI" in the day-of-week field means "the days Monday, Wednesday, and Friday".


Now, is it possible you to try ?
Gnana Prasuna
Greenhorn

Joined: Feb 18, 2009
Posts: 14
Thanks Sagar Rohankar for the reply.

1.)fire event at 12:30 start at 18/2/2009 and end by 25/2/2010.

0 30 12 ???2009-2010. For the above expression i am confused about how to build the month and day oy month fields.

can you correct the expression.

Thanks,
Prasuna





Sagar Rohankar
Ranch Hand

Joined: Feb 19, 2008
Posts: 2902
    
    1

Gnana Prasuna wrote:
1.)fire event at 12:30 start at 18/2/2009 and end by 25/2/2010.

0 30 12 ???2009-2010. For the above expression i am confused about how to build the month and day oy month fields.



Ok, I'm happy with your efforts shown. Now, you can NOT mentioned the the start and end date in trigger expression and that's not the place where we should mention it.. We have API for Trigger class which contain the methods for starting and stopping the trigger. Look the JavaDocs and search for the methods.

Now about the expression:



And of course, this will work as you wanted provided, you set start and end time..
Gnana Prasuna
Greenhorn

Joined: Feb 18, 2009
Posts: 14
Thanks Sagar Rohankar for your help and support.

Is there any possible way for firing the expression for particular no of occurences like for example my expression is 0 30 12 * * MON-FRI 2009-2010.In this case i would like to fire the expression for only 10 times or occurences. Is this case valid?

Thanks,
Prasuna.
Sagar Rohankar
Ranch Hand

Joined: Feb 19, 2008
Posts: 2902
    
    1

Gnana Prasuna wrote: i would like to fire the expression for only 10 times or occurences. Is this case valid?


Generally this is not valid, But you can modify expression so that its bound to execute only 10 times.. like, say, You want to execute Job from 10-02-2009 to 10-12-2009, Now we Know that the months are 10, So make the expression, which reads as " fire at every end of month for the year 2009"..
Gnana Prasuna
Greenhorn

Joined: Feb 18, 2009
Posts: 14
Thanks Sagar Rohankar for the reply.


If we set the start date and end date using API methods is it necessary to mention years in the cron expression.

Thanks,
Prasuna.
Sagar Rohankar
Ranch Hand

Joined: Feb 19, 2008
Posts: 2902
    
    1

Yes, when you say "Date" it has, day, month and year..

See the method, for CronTrigger#setStartTime(Date date) for details..

We are talking about Quartz, without referring its name, yet..
Gnana Prasuna
Greenhorn

Joined: Feb 18, 2009
Posts: 14
In CronTrigger we have methaod of setting the cron expression. If we set start date and end date using CronTrigger method then my question is if we didn't mention year fied will it work?

For Ex fire at evey 12:30 start at 25/2/2009 and end at 30/5/2011

'0 30 12 * * ? ' and i will set start date and end date using cronTrigger. will it fire as mentioned above?

Thanks,
Prasuna.
Sagar Rohankar
Ranch Hand

Joined: Feb 19, 2008
Posts: 2902
    
    1

Gnana Prasuna wrote:

'0 30 12 * * ? ' and i will set start date and end date using cronTrigger. will it fire as mentioned above?


When you said "0 30 12 * * ?", It's an incomplete cron expression..So you need to provide a YEAR field. And as you said, you are setting start and end date, that's mean you don't care about the cron expressions year field, so set the "special character", either ? or *.

So the final expression will be, "0 30 12 * * ? *"

Gnana Prasuna
Greenhorn

Joined: Feb 18, 2009
Posts: 14
Thanks Sagar Rohankar for your reply..

Fires every 2 days at 11:30 start at 21/3/2009 and end at 25/5/2010

0 30 11 21/2 * ? ? and i will set start and end date using cronTrigger. Is this expression correct for the abobe fire?

For day of month i used 21/2 because start date is 21 and for every 2 days it has to fire and shall i use under month field as 3/1 instaed of * which means start at 3rd month and increment by 1.

Thanks,
Prasuna.
Sagar Rohankar
Ranch Hand

Joined: Feb 19, 2008
Posts: 2902
    
    1

Gnana Prasuna wrote:Thanks Sagar Rohankar for your reply..

Please, Don't thanks too many times, What I really doing is , reading Quartz API and telling you, so nothing special....

Gnana Prasuna wrote:
Fires every 2 days at 11:30 start at 21/3/2009 and end at 25/5/2010

0 30 11 21/2 * ? ? and i will set start and end date using cronTrigger. Is this expression correct for the abobe fire?

For day of month i used 21/2 because start date is 21 and for every 2 days it has to fire ....


Part of expression is correct, i.e incrementing "day" by two, but "21/2" lefts it increments a day from 21st day and this is no we wanted, so make it for *all* day of month, by specifying .. */2

So the correct expression ll be : 0 30 11 */2 * ? ?
(Don't worry, it will start from 21st as, you set start date as "21/3/2009" )

Gnana Prasuna wrote:
.....and shall i use under month field as 3/1 instaed of * which means start at 3rd month and increment by 1.


No Need, as I explain above..
Gnana Prasuna
Greenhorn

Joined: Feb 18, 2009
Posts: 14
Hi All,

can some body help me on how to build cron expression for the below event.

fire event on first week day of every month.

Thanks,
Prasuna.
Sagar Rohankar
Ranch Hand

Joined: Feb 19, 2008
Posts: 2902
    
    1

Gnana Prasuna wrote:


fire event on first week day of every month.



You're not learning Quartz expression here, just by asking Ranchers !!
I told you in very first reply of mine that, you have to show your efforts first. What you got so far ? Where you stuck ?
 
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subject: Generating Cron Expression