In Sect. 13.1.2 we have mentioned the UML. This is a modelling language based on a set of diagrams describing various aspects of the problem solved:
We will use only class diagrams in this article.
The class in the class diagram is presented as a rectangle containing
the name of the class. It usually contains also the names of the
methods and the names of the attributes; both may be prefixed by
symbols representing their access specification (the sign
for public members, the
sign for private members and the
for protected ones). The name, the attributes and the
methods are in the class icon separated by horizontal lines. If not
necessary, attributes and methods may be omitted. Figure 13.1
shows the icon of the Source class as we have designed it in
Sect. 13.2.4.
Associations (i.e., any relations) among classes in UML class diagrams are represented by lines connecting the class icons ended by arrows; as a description, the multiplicity of the relation may be given. For example, the number appended to the line connecting the Source and the Particle classes in Fig. 13.2 express the fact that one particle source may emit any number of particles. The number appended to the line connecting the Source and the Generator class express the fact that one source uses only one random number generator.
Object composition is expressed by the arrow ending with a filled diamond. Fig. 13.2 shows relations among the Source, Particle, and Generator classes. Simplified class icons are used.