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Next: Section BASE CLASSES Up: Description Class Previous: Sections REQUIREMENT SPECIFICATIONS, MACHINE

Section FORMAL PARAMETERS

In order to be able to define description classes more generally, it is possible to use parameters. In a problem specification there are two kinds of parameters: domain parameters and number parameters. Both kinds are illustrated using an example.

Consider different kinds of sensors, for example a temperature and a light sensor. They differ in the values they measure and deliver. Nevertheless, such sensors share common properties. To present such properties only once a general class Sensor is introduced. Special sensors like temperature or light sensor can then be derived from this general class, cf. Section 2.1.6. In the general description class Sensor the domains are only introduced but not specified. In the following example these are the domains ENV_DOMAIN and MEASURED_DOMAIN.

\fbox{
\begin{minipage}{13cm}
\textbf{\large Description Class Sensor}
\par \vsp...
...urned by the sensor.
\end{tabular}\par \hspace*{1cm}$\vdots$\par \end{minipage}}

Example: Domain Parameter

Let us now consider an example for number parameters. Usually different rooms differ in the number of windows they have. In order to be able to describe common properties of rooms this number is expressed as a parameter. In the following example this is the parameter numWin.

\fbox{
\begin{minipage}{13cm}
\textbf{\large Description Class Room}
\par \vspac...
...
belong to a room.
\end{tabular}\par \hspace*{1cm}$\vdots$\par \end{minipage}}

Example: Number Parameter


next up previous
Next: Section BASE CLASSES Up: Description Class Previous: Sections REQUIREMENT SPECIFICATIONS, MACHINE
Forest-System
1999-06-04