Chapter 8. Timers

You can set a timer with delay and a certain period. The delay specifies the waiting time after the node activation, and the period defines the time between the subsequent trigger activation. The period value 0 results in a one-shot timer. You can specify the delay and period expression in [#d][#h][#m][#s][#[ms]] form, indicating the number of days, hours, minutes, seconds, and milliseconds (default). For example, the expression 1h indicates one hour waiting time before triggering the timer again.

You can configure timers with ISO-8601 date format that supports both one-shot timers and repeatable timers. You can define timers as date and time representation, time duration, or repeating intervals. For example:

You can also specify timers using process variables, consisting of the string representation of delay and period or ISO8601 date format. When you specify #{variable}, the engine parses the expression and replaces the expression value with the variable. In a process, you can use timers using the following ways:

In some cases, the scheduled timer needs to be rescheduled to accommodate the new requirements, such as changing delay, period, or repeat limit. Updating a timer includes many low-level operations, therefore, Red Hat Process Automation Manager provides the following command to perform the low-level operations related to updating a timer as an atomic operation. The following command ensures that all the operations are performed within the same transaction.

org.jbpm.process.instance.command.UpdateTimerCommand

You can reschedule the timer by specifying the two mandatory parameters and one of the three optional parameter sets of the UpdateTimerCommand class.

// Start the process instance and record its ID:
long id = kieSession.startProcess(BOUNDARY_PROCESS_NAME).getId();

// Set the timer delay to 3 seconds:
kieSession.execute(new UpdateTimerCommand(id, BOUNDARY_TIMER_ATTACHED_TO_NAME, 3));