BPMN Inclusive Gateway

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BPMN Inclusive Gateway

The BPMN Inclusive Gateway article provides a detailed explanation of the Inclusive Gateway BPMN element, including the definition, notation, rules, guidelines and examples.

The BPMN Inclusive Gateway article delves deep into the intricacies and applications of the inclusive gateway element as outlined in the BPMN 2.0 specification. The definition, notation, and rules sections offer a concise summary of the BPMN 2.0 Specification pertaining to the inclusive gateway element. Meanwhile, the guidelines section presents a curated collection of best practices specific to the inclusive gateway, showcasing its proper and effective utilisation in process modelling.

What is an Inclusive Gateway?

“A diverging Inclusive Gateway (Inclusive Decision) can be used to create alternative but also parallel paths within a process flow. A default path can optionally be identified, to be taken in the event that none of the conditional expressions evaluate to true. A converging Inclusive Gateway is used to merge a combination of alternative and parallel paths. A control flow token arriving at an Inclusive Gateway MAY be synchronized with some other tokens that arrive later at this Gateway.” ~ BPMN Specification

Example: Order Coffee Process

The Place Order process illustrates the use of the inclusive gateway to make a decision based on the outcome of a task. The process starts of with a task to place an order. Based on the outcome of this task, the process determines whether the customer “Ordered Coffee” or “Ordered Muffin” or both. If no decision was made, the default task to give a free sample is performed. After the order is fulfilled, the final task to deliver the coffee order is performed.

Inclusive Gateway Example Example of an inclusive gateway

The converging inclusive gateway merges the sequence flows from the different tasks based on the choice of order. The incoming sequence flow tokens will be synchronised first (waiting on other tokens), before being routed to the outgoing sequence flow.

Key Difference

  • Exclusive Gateway: A maximum of one sequence flow may be traversed by a token.
  • Inclusive Gateway: More than one sequence flow may be traversed by a token

Guidelines

  • The inclusive gateway is also referred to as OR.
  • Each of the sequence flow’s condition expression are evaluated.
  • The true evaluation of one condition Expression does not exclude the evaluation of other condition Expressions.
  • All Sequence Flows with a true evaluation will be traversed by a token.
  • Since each path is considered to be independent, all combinations of the paths MAY be taken, from zero to all.
  • Inclusive Gateways should be designed that at least one path is taken to avoid runtime exceptions. (See Default Path)
  • The default flow will be used only if all the other outgoing conditional flow is not true at runtime.
  • The default Sequence Flow should not have a conditionExpression.

Finally

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Reference