General Activity Icons
An activity is the primary graphic element in activity charts that represent a function in the functional view of the system. An activity represents something that transforms inputs into outputs.
There are three types of activities:
Activities can be allocated to modules (structure) and can contain statecharts. You can specify the behavior of an activity by connecting it to a subroutine.
● Internal primitive activities (reactive-controlled and reactive-self) can be connected to tasks (no mini-specs or decomposition is allowed).
Create Internal Activity - creates an internal activity. Name Existing Activity - Names an existing activity. Create Control Activity - creates a control activity. The control activity senses and controls the status of sibling activities. If an activity does not contain a control activity, the children of the activity are active when the parent is active. Control activities cannot be hierarchically decomposed. Only one control activity is allowed per activity hierarchical level.A control activity cannot have any subactivities and is specified by an off-page statechart or flowchart. An @ symbol precedes the title of control activities. Create External Activity - creates an external activity, which is an activity outside the scope of the topmost activity in a particular activity chart.Because activity charts are hierarchical, an external activity is usually resolved to a box in a chart higher in the chart hierarchy. However, an external activity can be resolved to a box that is an internal activity at a higher level. In this case it remains simply an external activity when referenced in the lower chart.External activities cannot be hierarchically decomposed. There can be more than one occurrence of the same external activity.