A diverging Exclusive Gateway (Decision) is used to create alternative paths within a process flow. This is basically the diversion point in the road for a process. Only one alternative path can be taken for a given instance of the process.
A Exclusive Gateway can be thought of as a question that is asked at a particular point in the process. The question has a defined set of alternative answers. Each question is associated with two or more condition expressions associated with outgoing sequence flows of the Gateway.
A converging Exclusive Gateway is used to merge alternative paths. All incoming sequence Flows tokens will be routed to the outgoing sequence flow without synchronizing them.
Note
There are two icons defined for an Exclusive Gateway in the BPMN2 Specification.It can be displayed with or without an internal marker.
Notation
Without an Internal Marker Exclusive Gateway Image Modified
An Internal Marker Exclusive Gateway Image Modified
