Flows and Links (BPMN)

BPMN provides various kinds of flows and links to connect objects in collaboration, conversation, and choreography diagrams.

The following types of flows and links are available:

Tool	Description
	Sequence Flow - Connects events, activities, and gateways in processes in collaboration, process, and choreography diagrams.
	Message Flow - Connects participants in collaboration diagrams. Connects message symbols to participant bands on choreography tasks in choreography diagrams.
	Data Association - Connects data objects to activities or events in collaboration and process diagrams.
	Conversation Link - Connects participants in conversation diagrams.

Sequence and Message Flow Properties

Sequence and Message Flows are based on and have the same properties as standard flows (see Flow Properties). Message flows have the following additional properties:

Property	Description
Correlation key	Specifies the correlation key (set of correlation properties drawn from the message) used to associate the message to a particular instance of a process (see Correlation Keys (BPM)). Each flow must have the same key as the conversation node to which it is connected.
Correlation property	Specifies the correlation property that acts as the unique identifier for this instance of the message (see Variables (BPM)).

Note: To set a sequence flow to the default flow, right-click the flow and select Set to Default Flow. The source of a default flow must be of an origin of an inclusive, exclusive, or complex gateway or an activity.

Data Association Properties

Data associations are based on and have the same properties as resource flows (see Resource Flows (BPM)), with the following additional properties:

Property	Description
Transformation type	Specifies the direction of the transfer of the item-aware element, with input meaning a data read and output a data write.
Source / Target item	Specifies the item-aware element to be transferred.

Conversation Link Properties

Conversation links 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.
Stereotype	Extends the semantics of the object. You can enter a stereotype directly in this field, or add stereotypes to the list by specifying them in an extension file.
Participant	Specifies the participant to which the link is joined.
Conversation node	Specifies the conversation node to which the link is joined. Use the tools to the right of the list to create, browse for, or view the properties of the currently selected object.
Keywords	Provide a way of loosely grouping objects through tagging. To enter multiple keywords, separate them with commas.