Connecting Objects

What Connecting Objects Are

In BPMN 2.0, connecting objects define the relationships and flow of information between elements in a process model. They link activities, events, and gateways, guiding the process flow or conveying data and messages. The primary connecting objects are sequence flows, message flows, and associations. You can connect elements with these objects in the ProcessMind modeler — start a free trial to try them on your own process.

Sequence Flow

A sequence flow defines the order in which activities, events, and gateways are performed in a process. It shows the logical progression of tasks from one step to the next.

• Example: A sequence flow connects a “Submit Application” task to a “Review Application” task, showing that the review follows the submission.
• Types of Sequence Flows:
  • Normal Sequence Flow: The default flow between activities.
  • Conditional Sequence Flow: A sequence flow that only proceeds if a specific condition is met (indicated by a small diamond).
  • Default Sequence Flow: The fallback flow if no conditions are met (indicated by a diagonal slash at the starting point).
• Use Case: Use sequence flows to guide the step-by-step progression of a process, ensuring activities are executed in the correct order.

Message Flow

A message flow represents communication between different participants or processes, typically when they are part of different pools. It is used to show the exchange of information between processes, which might be operating independently.

• Example: A message flow connects a “Send Invoice” task in one pool (the supplier) to a “Receive Invoice” task in another pool (the customer), showing that the invoice is sent between them.
• Use Case: Use message flows to illustrate communication between different entities or business participants, such as when one company sends an order request to another.

Association

An association connects artifacts (such as data objects, text annotations, or groups) with flow objects (activities, events, gateways) to provide context or clarify relationships. Associations do not impact the sequence of the process but are used for documentation and additional details.

• Example: An association connects a “Generate Report” task to a “Report Document” (a data object), showing that this task produces the document.
• Types of Associations:
  • Normal Association: Connects elements like tasks to data objects or annotations.
  • Directional Association: Shows the flow of data from or to a task (indicated with an arrow).
  • Bi-Directional Association: Indicates two-way relationships between elements (shown with two arrowheads).
• Use Case: Use associations to link additional information, such as data objects or text annotations, to tasks or events without affecting the process flow.

Example

Imagine a process for managing customer orders:

• Sequence Flow: After receiving an order, the system processes the order and then sends it for delivery. Each step (receiving, processing, delivering) is connected by sequence flows.
• Message Flow: Once the order is processed, a message is sent to an external shipping company to handle delivery. This communication is represented by a message flow between the two entities.
• Association: A “Customer Order” data object is associated with the “Receive Order” task to show that this task deals with order data.

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Related topics

• Gateways: control the flow between elements.
• Activities: the main activity types.