Tallis Training

Non-linear processes: Event Triggers

Event Triggers: Offering the end-user a choice between tasks

An event trigger is a text string that enables tasks to respond to events taking place outside the scope of the process-description.

The event trigger is useful for creating processes that do not have a predefined workflow. Event triggers allow end-users to trigger specific tasks at any point in time, regardless of the scheduling constraints or the state of the process-description. This allows for non-linear processes: end-users can choose between tasks, skip tasks and even re-run tasks.

Example: A clinician in a patient consultation may choose to invoke one of a number of services by selecting the relevant event trigger for each (e.g. “perform_biopsy”, or “perform_imaging”, or “discharge_patient”, etc.)


  • A task with an event trigger does not execute unless the trigger is invoked, even if all scheduling conditions are met.
  • When the trigger is invoked, the task executes, even if scheduling conditions are not met.
  • The task state returns to dormant after completion – tasks with event triggers can be re-activated.

Browse through a process-description sample:

  • ERA
  • This process is a collection of simple workflows, each enclosed within a “triggerable” plan. The Introduction action serves as a menu: it contains a list of hyperlinks that are linked to the appropriate event triggers, and allows the end-user to select between the available sub-processes.
  • If you have installed the Tallis Toolset, you can find this sample in the World > Samples folder in the ACL Web Repository.
  • Run this sample file
  • Click here for a detailed description of this sample.

See Also

Top | «Prev | Next»

Last update: