BPMN Message Event

in BPMN on Bpmn, Bpmn 2.0, Message event
BPMN Message Event

The BPMN Message Event article provides a detailed explanation of the message event element, including the BPMN notation, an example diagram and guidelines.

The BPMN Message Event article focus on the definition and usage of the message event element as documented in the BPMN 2.0 specification. The example process diagram illustrates the correct use of the message event annotation. The BPMN Guidelines section contains a detailed set of rules that apply to the message event and explains how the element may or may not be used within the different BPMN diagrams.

What is a Message Event?

“A BPMN Event that references a named message is known as a Message Event. A Message represents the content of a communication between two Participants.” ~ BPMN Specification

Message events are used to send and receive messages between two distinct processes. Message Events may be used as a mechanism for two processes to communicate.

BPMN Notation

The BPMN specification defines the Message Event element using the following description and notation:

Catching EventsThrowing Events
Start EventIntermediate EventEnd Event
StandardEvent Sub-Process
Interrupting		Event Sub-Process
Non-Interrupting		CatchingBoundary
Interrupting		Boundary Non-
Interrupting		ThrowingStandard
Message Event

BPMN Notation: Message Event

BPMN Event Types

The following table contains a list of the different Message Event types, their descriptions and the BPMN notations:

ElementDescriptionNotation
Message Start EventA Message arrives from a Participant and triggers the start of the Process.
Message Event Sub-Process Event (Interrupting)A Message Event can also initiate an inline Event Sub-Process. A Message Event Sub-Process that interrupts its containing Process is known as a Message Event Sub-Process Event (Interrupting).
Message Event Sub-process Event (Non-Interrupting)A Message Event can also initiate an inline Event Sub-Process. A Message Event Sub-Process that does not interrupt its containing Process is known as a Message Event Sub-Process Event (Non-Interrupting).
Message Intermediate Catch EventA Message Intermediate Catch Event can be used to receive a Message.
Message Boundary Event (Interrupting)A boundary event is an event that is attached to the boundary of an activity. A Message arrives from a participant and triggers the Event. A Message Boundary Event (Interrupting) is attached to an activity and will interrupt the activity.
Message Boundary Event (Non-Interrupting)A boundary event is an event that is attached to the boundary of an activity. A Message arrives from a participant and triggers the Event. A Message Boundary Event (Non-Interrupting) is attached to an activity and will not interrupt the activity.
Message Intermediate Throw EventA Message Intermediate Throw Event can be used to send a Message.
Message End EventA Message End Event can be used to send a Message once the token reach the end event and then terminate the process.

BPMN Event Types: Message Events

BPMN Diagram

The following is an example of a BPMN Message Event within a diagram:

BPMN Message Event Example of BPMN Message Event

BPMN Standards & Guidelines

The difference between standard and guideline is that a standard is a level of quality or attainment while a guideline is a non-specific rule or principle that provides direction to action or behaviour. A standard are high in authority and needs to be adhered to versus a guideline is low in authority and guide one in setting standards or determining a course of action.

BPMN Standards

The BPMN Standards section contains a list of rules that are applicable to the BPMN Message Event as per the official rules of the BPMN Specification.

  • A Message Intermediate Event MAY be the target for a Message Flow; it can have one incoming Message Flow.
  • A Message Intermediate Event MAY be a source for a Message Flow; it can have one outgoing Message Flow.
  • A Message Intermediate Event MAY have an incoming Message Flow or an outgoing Message Flow, but not both.

BPMN Guidelines

The BPMN guidelines section contains a list of optional rules that can be used as a guide.

  • A Message Start Event should have a Text Annotation with text “Receive Message - [Message Name]”.

Finally

This article provided a detailed explanation of the BPMN Message Event element. Follow me on any of the different social media platforms, and feel free to leave comments.

Reference