Unified Modeling Language Reference Manual, The, Second Edition

control node

A activity node in an activity whose purpose is to coordinate control flows and object flows among other nodes; a specific flow-of-control construct.

See also activity.

Semantics

In an activity, simple flow of control from one node to another is modeled using control flow edges and data flow edges. An action begins execution when it receives tokens on all its input edges; when it completes execution, it produces to kens on all its output edges. More complex forms of control are modeled using control nodes, some of which do not require or produce tokens on all of their edges. Control nodes model decisions, concurrent forks, and starting and stopping an activity. Structured conditionals and loops are modeled using structured activity ...