Objects: Business Process Diagram
This type of Gateway splits the flow into two or more paths; the sequence flow will only continue on one of them. The conditions are expressed as Gateway attributes and can be set as a formal expression. The choice of the way forward is based on an assessment of the conditions imposed on each path. These are evaluated one by one in the order they were declared in the gateway and the path will be chosen for the first condition which evaluates to true. If neither condition is true, the process will be stalled in the Gateway therefore is suggested the use of a default path. Use an Inclusive Gateway if the process needs to activate more than one outgoing sequence flow.
Like the other gateways, this allows you to control a process splitting or merging. During the split, the flow will continue for only one path that can be traced in the Gateway, and the election will evaluate the conditions that are defined for the Gateway (will have one for each way). During the merge, where multiple paths arrive at the Gateway; it will simply continue the flow moving to the next Task. If another path arrives from another incoming Sequence Flow, then it will also pass straight through; there will be two instances of the following Task. If the desired behavior is that only the first one should pass through (ignoring the rest), then a Complex Gateway is needed.
Event Gateway (X Evolution 1)