=====BON/UML=====

  * For more on UML and BON see [[https://wiki.eecs.yorku.ca/project/eiffel/_media/bon:uml.pdf|UML/BON]] (logon)
  * [[https://www.eiffel.org/doc/eiffelstudio/Diagram%20tool|Using the EiffelStudio/BON diagram tool]] (can also be used for UML)
    * [[https://youtu.be/wQs6n3e2mpo?t=216|Short instruction Video using the IDE]] to generate a BON class diagram.
  * [[http://www.bon-method.com/index_normal.htm|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.
  * For drawing BON diagrams see [[:eiffel:faq:bon:|using draw.io for BON diagrams]]

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.




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

{{:bon:bon_diagram.png?800|}}

===BON Predicate Logic===

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

{{:bon:bon-predicate-logic2..png?600|}}


{{:bon:bon-predicate-logic1.png?600|}}

===Useful links===

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 [[https://wiki.eecs.yorku.ca/project/eiffel/_media/bon:bon-book.pdf|pdf]].

===Older Drawing Tools===
The graphical shapes of BON can be drawn using Microsoft Office Visio. We use draw.io instead. 

  * Using the [[https://wiki.eecs.yorku.ca/project/eiffel/_media/bon:bon-stencil.zip|BON Visio Stencil]] (**Visio 2013 and later**), we can draw BON class and dynamic diagrams. A [[https://wiki.eecs.yorku.ca/project/eiffel/_media/bon:bon-visio.pdf|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**.