Table 9.7 – ParticipantAssociation model associations

innerParticipantRef: Participant This attribute defines the Participant of the referenced element (e.g., a Choreography to be used in a Collaboration) that will be mapped to the parent element (e.g., the Collaboration).

outerParticipantRef: Participant This attribute defines the Participant of the parent element (e.g., a Collaboration references a Choreography) that will be mapped to the referenced element (e.g., the Choreography).

9.3.2Lanes

A Lane is a sub-partition within a Process (often within a Pool) and will extend the entire length of the Process level, either vertically (see Figure 10.123) or horizontally (see Figure 10.124). See page 304 for more information on Lanes.

9.4Message Flow

A Message Flow is used to show the flow of Messages between two Participants that are prepared to send and receive them.

A Message Flow MUST connect two separate Pools. They connect either to the Pool boundary or to Flow Objects within the Pool boundary. They MUST NOT connect two objects within the same Pool.

A Message Flow is a line with an open circle line start and an open arrowhead line end that MUST be drawn with a dashed single line (see Figure 9.11).

The use of text, color, size, and lines for a Message Flow MUST follow the rules defined in “Use of Text, Color, Size, and Lines in a Diagram” on page 39.

Figure 9.11 – A Message Flow

In Collaboration Diagrams (the view showing the Choreography Process Combined with Orchestration Processes), a Message Flow can be extended to show the Message that is passed from one Participant to another (see Figure 9.12).

Customer

Order

Confirmation

Supplier

Figure 9.12 – A Message Flow with an Attached Message

If a Choreography is included in the Collaboration, then the Message Flow will “pass-through” a Choreography Task as it connects from one Participant to another (see Figure 9.13).

Customer

Order

Continued...

Place

Order

Confirmation

Supplier

Figure 9.13 – A Message Flow passing through a Choreography Task

Figure 9.14 displays the class diagram of a Message Flow and its relationships to other BPMN elements. When a Message Flow is defined it is contained either within a Collaboration, a Choreography, or a

GlobalChoreographyTask.

Figure 9.14 – The Message Flow Class Diagram

The Message Flow element inherits the attributes and model associations of BaseElement (see Table 8.5). Table 9.8 presents the additional attributes and model associations for the Message Flow element.

Table 9.8 – Message Flow attributes and model associations

9.4.1Interaction Node

The InteractionNode element is used to provide a single element as the source and target Message Flow associations (see Figure 9.14, above) instead of the individual associations of the elements that can connect to Message Flows (see above). Only the Pool/Participant, Activity, and Event elements can connect to Message Flows. The InteractionNode element is also used to provide a single element for source and target of Conversation Links, see page 131.

The InteractionNode element does not have any attributes or model associations and does not inherit from any other BPMN element. Since Pools/Participants, Activities, and Events have their own attributes, model associations, and inheritances, additional attributes and model associations for the InteractionNode element are not necessary.

9.4.2Message Flow Associations

These elements are used to do mapping between two elements that both contain Message Flows. The MessageFlowAssociation provides the mechanism to match up the Message Flows.

A MessageFlowAssociation is used when an (outer) diagram with Message Flows contains an (inner) diagram that also has Message Flows. It is used when:

•A Collaboration references a Choreography for inclusion between the Collaboration’s Pools (Participants). The Message Flows of the Choreography (the inner diagram) need to be mapped to the Message Flows of the Collaboration (the outer diagram).

•A Collaboration references a Conversation that contains Message Flows. The Message Flows of the

Conversation can serve as a partial requirement for the Collaboration. Thus, the Message Flows of the Conversation (the inner diagram) need to be mapped to the Message Flows of the Collaboration (the outer diagram).

•A Choreography references a Conversation that contains Message Flows. The Message Flows of the

Conversation can serve as a partial requirement for the Choreography. Thus, the Message Flows of the Conversation (the inner diagram) need to be mapped to the Message Flows of the Choreography (the outer diagram).