Acknowledgments

Although the cover of any book features only the names of the authors, a book is always the result of the blood, sweat, and tears of many people. For their efforts in reviewing the first edition this book, we would like to thank Balbir Barn, Steve Cook, Wilfried van Hulzen, John Hogg, Jim Odell, and Cor Warmer. Special thanks go to Heidi Kuehn, who did a great job polishing our English.

Acknowledgments for their contributions to the first version of OCL must undoubtedly go to the following:

• The IBM team that developed the first version of OCL: Mark Skipper, Anna Karatza, Aldo Eisma, Steve Cook, and Jos Warmer.

• The joint submission team from IBM and ObjecTime. The ObjecTime team was composed of John Hogg, Bran Selic, and Garth Gullekson; and the IBM team consisted of Steve Cook, Dipayan Gangopadhyay, Mike Meier, Subrata Mitra, and Jos Warmer. On an individual basis, Marc Saaltink, Alan Wills, and Anneke Kleppe also contributed .

• The UML 1.1 team, especially the semi-formal subgroup of the UML core team: Guus Ramackers, Gunnar Overgaard, and Jos Warmer.

• Several people who influenced OCL during this period, most notably Desmond D'Souza, Alan Wills, Steve Cook, John Hogg, and James Rumbaugh.

• The many persons who gave their feedback on the earlier versions of OCL.

The following people are acknowledged for their contribution to the further development of OCL, that concluded in version 2.0 of the OMG standard:

• The members of the OCL 2.0 submission team: Tony Clark, Anders Ivner, Jonas H gstr m, Martin Gogolla, Mark Richters, Heinrich Hu mann, Steffen Zschaler, Simon Johnston, Anneke Kleppe, and Jos Warmer.

• The participants of the OCL workshops during the UML 2000, and UML 2001 conferences.

• People who made us aware of mistakes in the earlier edition of this book.

We would also like to thank all our teachers , colleagues, clients , and friends who in the past two decades made us aware of the need for a practical form of formalism in software development. Coming from a theoretical background (mathematics and theoretical computer science), we have always found sound formalisms appealing, but very early in our careers we decided that writing a two-page "proof" for five lines of code is not the right way to improve our software. We have been searching ever since for a way to combine our love for sound and complete formalisms with our sense of practicality. We hope and expect that OCL will prove to be just that: a practical formalism.

          Anneke  Kleppe  and  Jos  Warmer

          June  2003,  Soest,  Netherlands