In this lecture, we will analyze the structure and behavior of the Vendomatic1000 and the Vendomatic2000, using {\em class diagrams} and {\em collaboration diagrams}. First a brief introduction to some techniques used to design OO programs.

• CRC cards
  • CRC stands for Class, Responsibility, Collaboration
    • What are the classes?
    • What are the responsibilities?
    • How do the classes collaborate to solve the problem?
  • Useful to get a very high-level view of the problem before starting a serious design.
  • Invented by Ward Cunningham and Kent Beck in the 1980s (They used 4x6 cards but their format is more complicated than what we tried last week.)
  • Their original article on CRC cards can be found at http://c2.com/doc/oopsla89/paper.html if you are interested.

• UML
  • UML stand for Universal Modeling Language.
  • In the late 1980's and early 1990's a large number of competing methods for doing OO design arose.
  • In 1994 Jim Rumbaugh and Grady Booch, leaders of two major opposing software design methodologies Object Modeling Technique (OMT) and Object-Oriented Software Engineering (OOSE) respectively, joined forces at Rational Corporation to merge their methods into the Unified Method.
  • At OOPSLA '95, they released their first public version and announced that Ivar Jacobson (leader of another opposing faction) would be joining them. Jacobson, Rumbaugh and Booch are referred to as the three amigos.
  • In 1997 Rational released UML version 1.0 as a proposed standard to OMG (Object Management Group).
  • Arm-twisting followed and eventually, the remaining competing design approaches were merged.
  • UML version 1.3 was made public in Spring 1999.
  • UML is scheduled to become an ISO standard in 2001. (The Communications of the ACM, October 1999 had an entire issue devoted to UML.)
  • UML is a rich family of notation and meta-models (a diagram that defines a notation).
  • Besides imposing a standard language for OO design, increasingly sophisticated tools have evolved for managing software being designed using these techniques.
  • We will only talk about two meta-models in their simplest form: class diagrams and collaboration diagrams.

• Class Diagrams
  • Model structure.
  • Describe types of objects in the system (the classes) and their static relationships (associations and subtypes).
  • Each class is represented by a rectangle with the name at the top.
  • Associations often correspond to "has a", but could be other kinds. Associations are drawn with lines connecting the classes.
  • Subtypes represent "is a". The subtype relationship is drawn with an open-head arrow pointing from subtype to supertype.

• Collaboration Diagrams
  • Model behavior or interaction between objects.
  • The objects are represented by icons.
  • Messages (method calls) are represented by arrows that are labeled and numbered.
  • The sequence is represented by numbering. For example, 1: is the method call at the top level. 2: is the second method call at the top level. 1.1: indicates that in method call 1, another method was called.

• Vendomatic Family
  • Class and collaboration diagrams for Vendomatic1000.
  • Class and collaboration diagrams for Vendomatic2000.
  • What about the Vendomatic3000?