The control flows coming away from a decision node will have guard conditions which will allow control to flow if the guard condition is met. A shorthand notation for the above diagram would be to use input and output pins.Ī data store is shown as an object with the «datastore» keyword.ĭecision nodes and merge nodes have the same notation: a diamond shape. An object is shown as a rectangle.Īn object flow is shown as a connector with an arrowhead denoting the direction the object is being passed.Īn object flow must have an object on at least one of its ends. The difference between the two node types is that the flow final node denotes the end of a single control flow the activity final node denotes the end of all control flows within the activity.Īn object flow is a path along which objects or data can pass. The flow final node is depicted as a circle with a cross inside. The activity final node is depicted as a circle with a dot inside. There are two types of final node: activity and flow final nodes. Its notation is a line with an arrowhead.Īn initial or start node is depicted by a large black spot, as shown below. The following diagram shows an action with local pre- and post-conditions.Ī control flow shows the flow of control from one action to the next.

Actions are denoted by round-cornered rectangles.Ĭonstraints can be attached to an action. An activity is shown as a round-cornered rectangle enclosing all the actions, control flows and other elements that make up the activity.Īn action represents a single step within an activity. The following sections describe the elements that constitute an activity diagram.Īn activity is the specification of a parameterized sequence of behaviour. Activity diagrams are useful for business modelling where they are used for detailing the processes involved in business activities.Īn Example of an activity diagram is shown below. They may be used to detail situations where parallel processing may occur in the execution of some activities. Activity diagrams show the workflow from a start point to the finish point detailing the many decision paths that exist in the progression of events contained in the activity. In UML, an activity diagram is used to display the sequence of activities. UML 2 Tutorial - Activity Diagram Activity Diagrams

Sequence diagram parallel threads