Howdy, Comments. One of the nicest features of Core 2nd Ed. is that everywhere that a pattern or topic is referenced as part of an explanation, the authors thoughtfully included a (page number). Its almost a good as having an active link in the book. The other great advantage of this edition, to me, is the "micro architecture," which seems important to show learners how patterns might be glued together. I was delighted to see a concise pattern showing how adapters can be used to weld several other classifiers together. I think the reader would also be eager to see this concept extended to show how whole established Patterns can be similarly welded together. (Just a thought.) Questions. Q1. Each Core J2EE Pattern is beautifully and usefully layed out with great Class and Sequence Diagrams, side bars and so forth. Reference to other patterns in the literature (Hillside, etc.) is sprinkled around throughout the text. But the "Related Patterns" section includes mostly Patterns in the Core J2EE book itself only. Because of the overlap and historical evolution of many patterns, one thing I would have liked to see the Related Patterns or Known Uses section include citations to PLoPD and the many other sources. Would you consider a companion website to provide this kind of supplemental information? Q2. Although the Patterns maturely support DAO's for Entity persistence, the EJB 2.0 issues seem to be more folded into the discussion and, for me, a little harder to find. I feel that CMR's would have a drastic impact on some of the Core J2EE Business Tier Patterns, at least adding some new strategies to the canon. The Business Object and Value List Handler come to mind, maybe even the Dispatcher View. Some Core patterns may be out there that are specific to EJB 2.0, not just as incidental strategies within other patterns, especially when you consider how to properly weld patterns together to form a system architecture. What are your thoughts on my humble observations here? One more humble though on this. I would very much enjoy a companion website to include an extended Index into the text, or add and invite bleeding-edge strategies. Thanks in advance for your (authors) kind thoughts on these questions. John
Juan Rolando Prieur-Reza, M.S., LSSBB, SCEA, SCBCD, SCWCD, SCJP/1.6, IBM OOAD, SCSA
John, Thanks for your questions. Please see my comments below. Comments on Q1: We have primarily tried to highlight the relationships between Core J2EE Patterns amongst themselves because it is a very powerful way to understand our pattern catalog. Understanding inter-relatioships between these patterns in the book will help our readers to link the patterns together to solve larger problems and eventually to build micro-architectures. In the "Related Patterns" section, we also try to highlight relationships to GoF patterns, POSA (Patterns of Software Architecture: Vols. 1&2), and Patterns of Enterprise Architecture (Martin Fowler). If there are other patterns you see relationships to in PLoPD, etc., please let us know and we will look into including these references. You can email us at email@example.com to reach all the 3 authors. Regarding a companion website, we do have one at http://www.corej2eepatterns.com under which we would gladly include additional information useful to our readers. Comments on Q2: CMR does impact Business Object pattern and in particular impacts the Composite Entity pattern. Composite Entity is closely related to the Business Object pattern as it discusses the best way to implement business objects using entity beans. We discuss CMR in Composite Entity where relevant. Perhaps, in a future edition, we might include a richer discussion as a strategy of the Composite Entity pattern. Finally, regarding:
I would very much enjoy a companion website to include an extended Index into the text, or add and invite bleeding-edge strategies.
See comments above about companion site at http://www.corej2eepatterns.com . We would be happy to publish our reader's strategies under this site. Since we want to maintain cohesive information, we would be moderating such submissions. So please write to us about your strategies and we will publish them with proper attribution to you. You can email us at firstname.lastname@example.org .
- <b><i>Deepak Alur</i></b><br />Co-Author of <a href="http://www.corej2eepatterns.com" target="_blank" rel="nofollow">Core J2EE Patterns: Best Practices and Design Strategis</a>
I ordered the 2nd Ed of this book yesterday. I am correct when I state, some 2nd Ed. patterns are not yet on the website? Today, BookPool is selling 2nd Ed. for less than Amazon selling the 1st Ed. Today, informitIT is still on the 1st Ed. Don't get burned like I get burned so often.
Originally posted by Pradeep Bhat: How different is the book from the J2EE design patterns in the Sun site?
The book was recently released in June 2003 at JavaOne and is updated compared to the content on Sun site. I am assuming that the Sun site you are referring to is http://java.sun.com/blueprints/corej2eepatterns . The book is a lot different from the Sun site at this time: 1. Book contains 21 patterns (i.e. 6 new patterns compared to the Sun site) 2. All the patterns from the 1st edition (Sun site) have been revised and updated with new strategies, UML diagrams and sample code. 2. Book contains other material that is not on the sun site such as: 2a. J2EE Refactorings 2b. J2EE Bad practices 2c. J2EE Design Considerations 2d. a new chapter on a newly introduced concept called Micro-architecture. We currently have documented in the book one micro-architecture called Web Worker for integrating workflow into your J2EE web applications. A Micro-architecture is a set of patterns used together to realize parts of a system. We view Micro-architecture as a prescriptive solution derived from linking a set of patterns.