Event (BPMN)

In BPMN, which is a Business Processes modeling method, ‘Event’ means the Starting point or Ending point, etc. of Business operation. A Business Process starts at ‘Start Event’ and ends at ‘End Event’.


bpmn-20-elementsOMG Specification: Business Process Model and Notation 2.0.2 (page 29)


1. Overview

In BPMN, the <strong”occurrences” that take place in the middle of a series processing (Process) or coordination (Choreography) has been carried out are collectively referred to as Event. There are occurrences that affect business flow itself the (Catching type Event) such as “shipping time comes”, and also there are occurrences that affect third parties such as “sending a message” (Throwing type Event).

To represent these Events using the drawing notation in a Process Diagram, we use a round icon. The Start Event is represented with a “solid line circle”, an Intermediate Event with a “doubled line circle”, and an End Event with a “bold line circle”.

By the way, “working steps” such as ‘shipment’ or ‘create invoices’ are referred to as a Task (or activities), and is represented with a rounded corner rectangle. Moreover, the Events and Tasks, are collectively referred to as “BPMN Elements”.

Start Event is an instance that triggers the flow a new Issue on the Business Process. For example, “Someone makes application”, “Email arrives”, “Order process is finished.”

On some Start Event icons, a trigger for message or timer is marked. A Start Event can be a ‘Catch type Event’, but cannot be a ‘Throw type Event’. In addition, a starting point is not always only one, more than one start point can be defined in some cases.

Moreover, according to the specification of BPMN, the Start Event (and End Event) can be omitted. However, in many products of BPM and Workflow, these are mandatory.

- Start Event cannot be omitted in Questetra BPM Suite, either.

20141027-en-start-events-Sample: Multiple Start Events have been set

Intermediate Event represent the instance that occur in the middle of a Business Process.

In a Process Diagram, it is drawn with a double line circle. The “catching type” intermediate events are represented with the icon outlined , “throwing type” intermediate events are represented with the icon filled.

In addition, there are cases when an Intermediate Event is placed at the top of the flow (Sequence flow), and on the border line of the Task boundary (Boundary activities). When an event is placed on the task boundary, in case that an event occurs, before the operation finishes, it will be led into an exception path.

20141104-2-ja-intermediate-events-Sample: Intermediate Event on Task Boundary and on Sequence flow

End Event represents the point where a series of processing and collaboration in a Business Process ends. An End Event can be a ‘Catching type Event’, but cannot be a ‘Throwing type Event’.


2. Event type and Marker

BPMN Specification (2.0) defines The following Events.

For example, a Start Event (Leftmost column in the figure below) represents a trigger to start a new instance.

  • (No mark): Represents a Starting initiated by a human in Workflow and BPMS.
  • Message: Starting at receiving a message
  • Timer: Starting by a trigger which is done periodically or in a specific time
  • Error: (Starting in correspondence to submission of error when using sub-process)
  • Escalation: (Re-starting at changing personnel when using sub-process)
  • Compensation: (Re-starting if not completed when using sub-process)
  • Conditional: Starting when business environment or an external situation satisfies the conditional expression)
  • Signal: Starting in correspondence to a Throwing Signal Event on the instance flowing on Workflow
  • Multiple: Starting when one of multiple conditions is satisfied
  • Parallel Multiple: Starting when all of multiple conditions are satisfied

bpmn-20-events ‘Start Events’ (Solid line circle) are on the left side of “Catching” among all the Event elements
(Double line circles represent Intermediate Events, Bold line circles represent End Events)
(Note that, the dashed line circle is used in the cases that occur without stopping the original activity at the time of sub-processes and boundary expansion)


- In Questetra BPM Suite, there isn't a function to represent a 'sub-process' (including Inline Event type sub-process), because all the business process Definitions (Process models) are handled or connected equally. (as of version 10.0)


3. Utilization in BPMS

Although there are many cases in which all the elements can be described in Modeling products (Drawing tools), on the other hand, in many cases of BPMS products, they are limited to sub-sets of elements which have been defined in BPMN specification.

Note that, ‘Throwing Event’ now can be also described as ‘Throwing Task'(auto-processing), which raises confusion as there are two elements which behavior is completely the same in BPMS. (* These are the same functions in IBM BPM, difference in availability of placing Boundary event in Oracle BPM. Questetra BPM Suite does not provide a Throwing Task.)


4. Available BPMN Elements in Questetra

The BPMN elements that are available when you define a Business Processes in Questetra BPM Suite, a cloud-based BPMS product, are the following:


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Y. External Link