Swimlanes   Swimlanes divide or partition activity diagrams into a number of "lanes", which typically organize the diagram into a number of regions of responsibility. Each lane may have a name, which signifies the responsibility or governance of the elements that lie within it.

Explanation

Swimlanes are used on activity diagrams, and are a type of partition that divides the diagram up into a number of "lanes", like a swimming pool, to signify a grouping of the elements. They may be drawn vertically like columns or horizontally like rows. Activities, states and other elements such as objects and notes can be placed inside a lane. The flows between elements will cross over lane boundaries, the crossed lines have no meaning other than to represent a change from one lane or partition to another.

Important Points

The order of the "lanes" has no defined meaning.

The nature of the transitions from activity (action) to activity (action) results in some sensible arrangement of the "lanes", but the UML makes no statement as to its meaning, and they can be freely organized. Diagram layout and line crossing in practice will often dictate the relative positions of columns.

Related Entries

Action  Used Together An activity is related to swimlanes in the sense that if swimlanes are used then each activity will be in one (and only one) of the lanes. (They cannot sit on the fence). The swimlanes are typically used to represent responsibility or governance of the contained elements.