An interface is a collection of
operation signatures and/or attribute definitions that
ideally defines a cohesive set of behaviors. Interfaces
are implemented, "realized" in UML parlance, by classes
and components - to realize an interface, a class or
component must implement the operations and attributes
defined by the interface. Any given class or component
may implement zero or more interfaces, and one or more
classes or components can implement the same interface.
Depict One Interface Per Port.
Ports are connection
points between a classifier and its environment that
are depicted on the side of frames as small rectangles.
Figure 1 each port has exactly
one interface, which is logically cohesive and thus does
not reveal anything about the internal design of the Seminar component.
Depict One Port Per
Realizing Class. Another approach to organizing the
interfaces for SeminarComponent of
Figure 1would be to have a single port
offering the Enrollment, Transcript, and
DataEntity interfaces. This would make for a
more compact diagram although contradicts
Depict One Interface Per
Port: choose an approach and stick to it.
"Lollipop" Notation to Indicate Realization of an
Interface. As you can see in
Figure 2 there are two ways to
indicate that a class or component implements an
interface: the lollipop notation used with the Serializable interface and the realization line (the
dashed line with a closed arrowhead) used with the PersistentObject interface.