Start Events and End Events

Start events indicate the beginning of a process. End events indicate where a path of a process ends.

Implicit and Explicit Start and End Events

Use of start events and end events is optional. Other types of activities can be used to start a process, as long as they have no input mapping. Gateways can also be used to start a process. Similarly, other types of activities can be used to end a process, as long as they have no output mapping. These are known as implicit start events and implicit end events.

For an explicit start event, there must also be an explicit end event, and the reverse is also true. Also, if there are start and end events, implicit start and end events cannot be used. A process does not end until all start events have been visited, or in the case of implicit start events, all parallel paths have been completed.

Effect of Abnormal Termination

If a subprocess ends abnormally, the containing process does not terminate. If a multi-instance activity terminates abnormally, only the affected instance is terminated. (See Activity Loop Characteristics for an explanation of a multi-instance activity.)

Message Start and Signal Start Events

Message start and signal start events are configured using TIBCO BusinessEvents simple events. Validation checks at design time ensure that you use a correctly configured simple event:

  • Message start events require a simple event with a queue destination.
  • Signal start events require a simple event with a topic destination.

Example

As a simple example, suppose a process begins with a message start event and ends with a message end event. In such case, the process instance is instantiated when the simple event specified in a message start event arrives through a destination. The simple event properties appear as scope variables in the Output map, and you map them to process (job) variables, so they are available to the other activities later in the process.

At the end of the process the end event transfers the information available from the Input map (that is, values stored in the process variables) to the specified simple event’s properties and sends it to its default destination or specified destination.

Timer Start Events

The start of the process is triggered by a time-date or repeating time interval, for example, every Monday at 9am. In BPMN, the timer start event uses the TIBCO BusinessEvents time event trigger, therefore the event can be a repeating time event or a rule-based scheduled time event. See the TIBCO BusinessEvents timer event definition.