Schedule Apex Jobs Using Cron Expression in Salesforce

Biswajeet   September 8, 2015   No Comments on Schedule Apex Jobs Using Cron Expression in Salesforce

To schedule an apex job using Salesforce Cron Expression, you need to use System.Schedule apex method.

Scheduled Class:

global class AccountBatchScheduled implements Schedulable {
    global void execute(SchedulableContext ctx) {
        //Write your logic
    }
}

Scheduled Apex Class Using Cron Expression:

AccountBatchScheduled apexSch = new AccountBatchScheduled(); 
//Seconds, Minutes, Hours, Day of month, Month, Day of week, Optional year 
String CRON_EXP = '0 0 0 3 9 2 ?';
String jobID = System.schedule('AccountBatchScheduled Job', CRON_EXP, apexSch);

Cron Expression Values:

Name Values Special Characters
Seconds 0–59 None
Minutes 0–59 None
Hours 0–23 None
Day_of_month 1–31 , – * ? / L W
Month 1–12 or the following:

  • JAN
  • FEB
  • MAR
  • APR
  • MAY
  • JUN
  • JUL
  • AUG
  • SEP
  • OCT
  • NOV
  • DEC
 , – * /
Day_of_week 1–7 or the following:

  • SUN
  • MON
  • TUE
  • WED
  • THU
  • FRI
  • SAT
 , – * ? / L #
optional_year null or 1970–2099 , – * /

Cron Expression Special Characters:

Special Character Description
, Delimits values. For example, use JAN, MAR, APR to
specify more than one month.
– Specifies a range. For example, use JAN-MAR to specify
more than one month.
* Specifies all values. For example, if
Month is specified as *, the job is
scheduled for every month.
? Specifies no specific value. This is only
available for Day_of_month and
Day_of_week, and is generally
used when specifying a value for one and not the
other.
/ Specifies increments. The number before the
slash specifies when the intervals will begin, and
the number after the slash is the interval amount.
For example, if you specify 1/5 for
Day_of_month, the Apex class
runs every fifth day of the month, starting on the
first of the month.
L Specifies the end of a range (last). This
is only available for
Day_of_month and
Day_of_week. When used with
Day of month, L always means the
last day of the month, such as January 31,
February 29 for leap years, and so on. When used
with Day_of_week by itself, it
always means 7 or SAT. When used with a
Day_of_week value, it means the
last of that type of day in the month. For
example, if you specify 2L, you are
specifying the last Monday of the month. Do not
use a range of values with L as the results
might be unexpected.
W Specifies the nearest weekday
(Monday-Friday) of the given day. This is only
available for Day_of_month. For
example, if you specify 20W, and the 20th
is a Saturday, the class runs on the 19th. If you
specify 1W, and the first is a Saturday, the
class does not run in the previous month, but on
the third, which is the following Monday.

Use the L and W together to specify the last weekday
of the month.
# Specifies the nth day of
the month, in the format weekday#day_of_month.
This is only available for
Day_of_week. The number before
the #
specifies weekday (SUN-SAT). The number after the # specifies the
day of the month. For example, specifying 2#2 means the
class runs on the second Monday of every month.

Cron Expression Examples :

Expression Description
0 0 13 * * ? Class runs every day at 1 PM.
0 0 22 ? * 6L Class runs the last Friday of every month
at 10 PM.
0 0 10 ? * MON-FRI Class runs Monday through Friday at 10
AM.
0 0 20 * * ? 2010 Class runs every day at 8 PM during the
year 2010.