Software Engineering Documentation

BON - Business Object Notation. The BON method for analysis and design of object-oriented software is a means of extending the higher-level concepts of the Eiffel programming language into the realm of analysis and design aided by a graphical notation akin to but different from UML.

BON provides a textual and graphical notation for modelling the static and dynamic structure of OO software:

• BON has strong support for providing precise specifications of re-usable, industrial strength components via Design by Contract (preconditions, postconditions and class invariants), which includes subcontracting via the inheritance relationship. See example below.
• It supports a seamless method for turning software construction from specification to implementation into a single continuous process.
• It supports reversibility which is the ability to go back from implementation to specification.

BON is described in depth in the book Seamless Object-Oriented Software Architecture, Prentice Hall, 1994, by Kim Waldén and Jean-Marc Nerson. The textbook is now out of print but available from the BON website as a pdf.

The graphical shapes of BON can be drawn using Microsoft Office Visio (available on Windows workstations in the Prism Lab or for your Laptop – see links below).

• Using the BON Visio Stencil (Visio 2013 and later), we can draw BON class and dynamic diagrams. A BON/Visio manual is available describing how to use Visio for the BON diagrams.
• This is the https://wiki.eecs.yorku.ca/project/eiffel/_media/bon:bon-visio-stencil-original.zip for Visio2010.

Here is an example of a contracted class CITIZEN using the BON notation:

In BON diagrams, use mathematical notation to express contracts. See the BON textbook for more examples.