An Activity Diagram is a type of diagram in the Unified Modeling Language. The UML 2.0 Activity diagram has semantics based on Petri nets. The Interaction Overview diagram is based on the Activity diagram.
An Activity Diagram identifies a sequence of steps and the information that is transferred from one participating role to another. Sometimes called a “Swim-lane Diagram”, the pictures represent the flow of control among the steps and help identify when information is required to be transmitted to achieve the objectives of the Storyboard.
Following is an example of an Activity Diagram, an output of the process step – Capture Process Flow: Activity Diagram. Of particular interest in the data information exchange focus of HL7, are the Activity Diagram semantics that depict the passing of “objects” (e.g., data, information, messages, documents) between swim-lanes.