Object Modeling: Strategies, Patterns and Applications

Strategies, Patterns and Applications
Peter Coad, Mark Mayfield, David North

Peter Coad's book, Object Modeling: Strategies, Patterns and Applications, uses a number of simple example applications to introduce a set of strategies and patterns for building object models. This is followed by a reference section that lists the strategies and patterns discussed.

Published in 1997, this was the second Peter Coad book I read. Unlike my first encounter with Peter's books, Java Design, which I read from cover to cover in a single weekend and could not put down, this was a very different experience.

Possibly due to my level of experience at the time with object modeling I had to frequently put this book down to think through the points raised. It took me several readings to fully absorb (grok) all the content. I have returned to this book again and again over the years because of the richness of the content. In this way, the book is more akin to Peter's more recent Java Modeling in Color with UML book.

Indeed, the foundations of the modelling in colour technique and the class archetypes described in the Java Modeling in Color with UML are very evident in the Object Models book. The terminology has changed as Peter sought for names that communicated better: The Moment-Intervals of the JMCU book are called transactions. The Roles of the JMCU book are called Participants. Items have become Descriptions in the JMCU book, Specific Items have become Things, Actors have become Parties and so on.

In 1997 UML (have we really been using UML for a decade now?) was only just starting its march to dominance and its place as the de facto industry standard object modeling notation. Therefore, the book contains model diagrams in the old Coad notation, OMT, and UML. Unfortunately, the reference section is in Coad notation only. However, Coad notation is very easy to pick up with the only really irritating difference being that cardinalities (multiplicities) are on the opposite, and some would argue the more intuitive, ends of associations.

The book starts with a short preface that is well worth reading because it contains the definition of pattern and strategy used in the book. This followed by seven chapters and a handful of appendices.

The first five chapters each walk through building an object model for a simple but realistic sample application:

1. A point-of-sale application.
2. A warehousing application.
3. An order processing application
4. A soft real-time application.
5. A hard real-time application.

Chapter 6 rebuilds the same models nut this time from patterns instead of from scratch illustrating the power of combining proven patterns to rapidly build high-quality, object models.

Chapter 7 is a reference handbook listing all the strategies and patterns discussed in the first six chapters.

The appendices cover a variety of topics from use of patterns elsewhere to working with databases.

The index has entries for Beavis and Butthead but there are no references in the book to these two characters. The other major entry in that section of the index is for Grady Booch, another expert in the field of object modeling and one of the Three Amigos who authored the original UML notation. Illustrating the friendly rivalry between the two camps at the time, advocates of this book were able to answer people asking if it referenced Booch's work with, " Yes, look him up in the index. He is right there between Beavis and Butthead". However, the last laugh is Grady Booch's because the pages linked to his index entry mistakenly point to OMT diagrams. OMT is the notation of another of the three amigos, James Raumbaugh.