Mastering Gateways in Activiti BPMN with Examples

Business Process Model and Notation (BPMN) allows us to model complex workflows with clarity. In Activiti BPMN, gateways are crucial for directing the flow of processes. In this guide, we’ll explore all major types of gateways in Activiti, and provide clear BPMN diagrams to visualize each.

1. Exclusive Gateway (XOR)

Use Case: Decision-making where only one path is chosen. Diagram:

Description:

The exclusive gateway checks conditions on each outgoing sequence flow. The first condition that evaluates to true is followed. If no conditions are true, it may follow the default flow if defined.

${approved == true} // Approve path
${approved == false} // Reject path

2. Inclusive Gateway (OR)

Use Case: One or more branches may be taken simultaneously based on conditions.

Diagram:

Description:

Each outgoing flow is evaluated independently. Multiple paths may be followed if their conditions are met.

3. Parallel Gateway (AND)

Use Case: All paths are executed concurrently.

Diagram:

Description:

No conditions are required. It simply splits the flow into parallel branches or joins parallel flows together.

4. Event-Based Gateway

Use Case: Flow proceeds based on an event (timer, message, signal).

Diagram:

Description:

Waits for one of several possible events to occur. Only the branch whose event happens first is taken.

Typical Events:

• Timer Event
• Message Event

Conclusion

Gateways enable flexibility and control over your BPMN workflows. When designing Activiti processes, choose the right gateway based on your business logic, and always test with various inputs.