gateways

Complex Gateway

A Complex Gateway provides custom routing logic that cannot be expressed by other gateway types. It uses expressions to define arbitrary split and join behavior.

Category
gateways
BPMN Spec
Section 10.5.5
Icon Class
bpmn-icon-gateway-complex

What is a Complex Gateway?

A Complex Gateway handles routing scenarios too complex for standard gateways. It allows modelers to define custom split and join logic using expressions when standard AND/OR/XOR semantics do not fit.

Visual Representation

A Complex Gateway displays as a diamond shape containing an asterisk (*). The asterisk represents the custom/complex nature of its routing logic.

Key Characteristics

  • Custom logic: Defines routing using expressions or scripts
  • Flexible join rules: Can specify partial synchronization (e.g., 2 of 3 paths)
  • M of N patterns: Useful for quorum-based decisions
  • Last resort: Use only when other gateway types cannot model the scenario

Common Use Cases

Quorum Approval

Proceed when any 2 of 3 approvers respond, regardless of which two.

Majority Decision

Continue when the majority of parallel review paths complete successfully.

Custom Synchronization

Wait for specific combinations of paths based on runtime conditions.

Frequently Asked Questions

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