Gateways (BPMN Descriptive)

Gateways control the sequence flow of the process, and can split or merge the flow to show many decisions or simultaneous actions are required.

To create a gateway:

Select an object in the diagram and click (or click and drag) the Gateway tool in its context toolbar to create a new gateway after it in the sequence flow.
Click the Gateway tool in the bottom toolbar and click in the diagram.

By default, an exclusive gateway is created. To change to a parallel gateway, click the Properties tool and select Parallel Gateway. In BPMN 2.0 Descriptive, PowerDesigner supports these two types of gateways:

Symbol	Description
	Exclusive gateway - Only one outgoing branch is performed, depending on the condition.
	Parallel gateway - All outgoing branches are performed simultaneously.

To create an object following the gateway, click a tool on the gateway's context toolbar to create a task or other object after it in the control flow:

To create a second object in a new branch, reselect the gateway and click and drag a tool on its context toolbar to place the second object in a suitable position. By preference its flow should depart from a different corner of the gateway symbol:

To specify a condition on a sequence flow connecting the gateway to an object, select the flow and enter an appropriate value in the Condition Alias field in the Properties panel. The value is displayed in the diagram on the sequence flow near to the gateway:

You should add a condition to all sequence flows leaving the gateway. You can add further alternate sequence flows as necessary. In this example, once a purchase order is raised, an exclusive gateway controls the subsequent sequence flow based on the value of the order:

Gateways are also used to merge sequence flows when the two or more parallel or exclusive flows reunite to continue the process. In this case the two types of gateway have the following meanings:

Symbol	Description
	Exclusive gateway - Waits for one incoming branch to complete before continuing.
	Parallel gateway - Waits for all incoming branches to complete before continuing.

In this example, one of the approval tasks will arrive at the final exclusive gateway, which then triggers the sending of the purchase order:

Gateways can have the following properties:

Property	Description
Name/Code/Comment	Identify the object. The name should clearly convey the object's purpose to non-technical users, while the code, which is used for generating code or scripts, may be abbreviated, and should not normally include spaces. You can optionally add a comment to provide more detailed information about the object. By default the code is generated from the name by applying the naming conventions specified in the model options. To decouple name-code synchronization, click to release the = button to the right of the Code field.

Property

Description

Name/Code/Comment

Identify the object. The name should clearly convey the object's purpose to non-technical users, while the code, which is used for generating code or scripts, may be abbreviated, and should not normally include spaces. You can optionally add a comment to provide more detailed information about the object. By default the code is generated from the name by applying the naming conventions specified in the model options. To decouple name-code synchronization, click to release the = button to the right of the Code field.