Exclusive choice

This is yet another common pattern where the control flow is transferred to one and only one outgoing branch from the activity. This is based on data/conditions. These conditions are evaluated at runtime. In BPMN this pattern is supported by a construct called XOR gateway. There may be more than one outgoing sequence flows from the XOR gateway but one and only one will be enabled at runtime. In this example, the XOR gateway decides if the student identity has been validated or not. If identity is validated, the student can proceed and answer ques- tions; otherwise the student cannot appear in the examination.