16-03-2012, 02:11 PM
UML Activity Diagrams
Ch2A.ppt (Size: 399 KB / Downloads: 39)
Objectives
To read and write UML activity diagrams
To know when and how to use activity diagrams
Topics
Processes and process descriptions
Activity diagram notation
Activity diagram execution model
Making activity diagrams
Processes and Their Description
Process description notations describe design processes as well as computational processes we design.
Execution Model
Execution is modeled by tokens that are produced by action nodes, travel over action edges, and are consumed by action nodes.
When there is a token on every incoming edge of an action node, it consumes them and begins execution.
When an action node completes execution, it produces tokens on each of its outgoing edges.
An initial node produces a token on each outgoing edge when an activity begins.
An activity final node consumes a token available on any incoming edge and terminates the activity.