Information unit (UML)
Information unit (Engl. InformationItem ) is a model element in the Unified Modeling Language (UML), a modeling language for software and other systems. It describes very generally a piece of information that can be exchanged between elements of the modeled system.
Information units are used when the structured exchange of information between elements of a system is to be modeled without the model already defining the structural and representational details of the information.
Information unit is closely related to class because both are specializations of the classifier model element. However, the modeling properties of the information unit are severely limited. In contrast to classes, information units have no attributes or methods, do not take part in generalization relationships, cannot be endpoints of associations and may not be instantiated.
notation
The figure on the left shows two possible notations for an information unit. It is marked either with the keyword «information»or with a small black filled-in arrow pointing to the right.
Differences to UML 1.x
Information unit was newly introduced in version 2.0 of the UML.