Using Data-Based Gateways

Go Up to Gateways (BPM)

The Data-Based Decision is a branching point where the alternatives are based on conditional expressions contained within the outgoing Sequence Flow. Only one of the Alternatives is chosen.

In the following graphic, there are three alternative tasks that may be performed. The decision on which task is performed is based on the boolean expression contained in the Condition Expression attribute of the outgoing Sequence Flow of the Gateway. The expression uses the values of process data to determine which path is taken.

Using Event-Based Gateways

An Event-Based decision represents a branching point where the alternatives are based on an event that occurs at that point in the Process. The specific Event, such as the receipt of a Message or a Timer event, determines which of the paths will be taken. Only one of the Alternatives is chosen. The following example shows an event-based gateway using message events.

Using Exclusive Event-Based Gateways

Exclusive Event-Based gateways represent a branching point in a Process or Choreography where the alternatives are based on an event that occurs at that point. An Event-Based Gateway is considered Exclusive in a Process when the senders following the gateway are the same and the choice of which message to send depends on the same participant. The following example shows an exclusive event-based gateway using message events.

Using Inclusive Gateways

Inclusive gateways provide more than one possible outcome. There is usually a corresponding merging inclusive gateway. The following example shows a number of chapters in a book that may be included in a book.

Using Complex Gateways

A Complex Gateway is used to handle situations that are not easily handled through the other types of Gateways. Complex Gateways can also be used to combine a set of linked simple Gateways into a single, more compact situation. Complex behavior can be defined for both the merging and splitting behavior.

Using Parallel Gateways

Parallel Gateways are places in the Process where multiple parallel paths are defined. Events on parallel outcome paths execute simultaneously and independently of each other. You can create a decision point that directs the process flow down multiple flows so activities are executed in parallel (instead of executing in sequence). These flows can then be reunited into a single flow to complete the task. The process execution waits until the last task in each parallel flow has been completed. The following example shows two parallel gateways. The task following the second gateway is executed only after all the parallel paths are completed.