Edit] General Relationship

Class diagram showing dependency between "Car" class and "Wheel" class (An even clearer example would be "Car depends on Fuel", because Car already aggregates (and not just uses) Wheel)

Edit] Dependency

Dependency is a weaker form of relationship which indicates that one class depends on another because it uses it at some point of time. One class depends on another if the latter is a parameter variable or local variable of a method of the former. This is different from an association, where an attribute of the former is an instance of the latter.

Edit] Multiplicity

The association relationship indicates that (at least) one of the two related classes makes reference to the other. In contrast with the generalization relationship, this is most easily understood through the phrase 'A has a B' (a mother cat has kittens, kittens have a mother cat).

The UML representation of an association is a line with an optional arrowhead indicating the role of the object(s) in the relationship, and an optional notation at each end indicating the multiplicity of instances of that entity (the number of objects that participate in the association).

Edit] Analysis Stereotypes

In the early stages of a project's technical analysis, class diagrams can be used to produce early conceptual models of the system. Classes at this stage often take the form of boundaries, controls and entities and rarely survive into the design without heavy changes.

Edit] Boundaries

Boundary classes handle the communication between actors and the system's internal components. They might be user interfaces, system interfaces or device interfaces (for example). They are identified by each actor–use-case pair on the system's use-case diagram, with one and only one boundary class existing for each pair.

They are drawn as circles with a short line to the left attached to a vertical line the same height as the circle (as though it is attached to the side of the use-case system boundary). Alternatively, they can be drawn as normal classes with the «boundary» stereotype notation above the class name.

Edit] Entities

Entity classes model the information handled by the system, and sometimes the behaviour associated with the information. They should not be identified as database tables or other data-stores.

They are drawn as circles with a short line attached to the bottom of the circle. Alternatively, they can be drawn as normal classes with the «entity» stereotype notation above the class name

Edit] Controls

Control classes handle the flow of control for a use-case and can therefore be seen as co-ordinating representation classes. These do not do everything in the use case, but co-ordinate with other classes that can do the work for them.

Date: 2016-03-03; view: 966