Slashdot Mirror


Patterns of Enterprise Application Architecture

Duane Gran contributes this review of Patterns of Enterprise Application Architecture, writing "The title of this book is a mouthful and the author, Martin Fowler, confronts headfirst complex topics of concern to software developers and architects. Fowler is a respected figure in software engineering circles, and his latest book is an attempt to codify best practices he learned in the trenches and through peer relationships. Many of the patterns will resonate with experienced developers, but Fowler's talent explaining abstract concepts will afford even the most grizzled reader many 'aha!' moments." Read on for the rest of Duane's review. Patterns of Enterprise Application Architecture author Martin Fowler pages 560 publisher Addison Wesley Professional rating 10/10 reviewer Duane Gran ISBN 0321127420 summary Excellent analysis of complex problem solving

The book is honest and upfront about grey areas in addition to (nearly) hard and fast rules. Fifty one patterns are described in an organized fashion, grouped by theme. The first section gives an overall narrative tying together the concepts while the remaining 4/5 of the book is devoted to short chapters on each pattern. In this way the book works well on two levels, as a reference and a tutorial. Code examples are given in Java and C# where most appropriate for the given pattern, however most examples use Java.

Much of the book centers around the task of Object-Relational mapping between the in-memory model of an application and the datastore. There are a surprising number of design choices in enterprise systems and I often found myself nodding in agreement with the logic behind the patterns. After establishing that mixing presentation and domain logic is a mistake worthy of horse-whipping, a plethora of smart alternatives are given.

I found this to be one of the more enlightening books I've read, and place it alongside Effective Java and Design Patterns Explained as canonical books for the Java developer. I'm a fan of the O'Reilly Java series, which excels in the HOW-TO category of books, but I've recently taken to the Addison-Wesley publications, which deal less with the nuts and bolts, and for lack of a better word are more like WHY-TO books.

Aside from being an excellent book, I also liked that it is hardbound and includes a bookmark (simple nylon strap from the binding). This is a fitting presentation for such a quality book.

The only complaint I might have is that sometimes the code examples are a tad brief for my taste. The author is fond of declaring a class as follows:

class ArtistMapper ...

From the UML diagrams provided I was often able to conclude that ArtistMapper extends AbstractMapper or that ArtistMapper implements Mapper, but as I read the examples I yearned for completeness. Two guesses come to mind as for this choice:

  1. The author explains that the code examples are meant to facilitate understanding, not to provide boilerplate code. Fowler's appreciation for the complexity of software systems leads him to caution the reader to implement the examples without careful consideration to the context in which they are deployed. Partial code examples forces the reader to fill the gaps, and in the process may think more critically about it.
  2. There is often more than one way to do things, like abstracting an interface in Java. The choice of extending an Abstract class or implementing an interface implies a subtle, but far-reaching, development choice. Similar to the previous point, I think Fowler may want the reader to choose a concrete class implementation appropriate for his or her application.
On the whole, I really enjoyed the book and would recommend it without hesitation to fellow software developers and architects.

You can purchase Patterns of Enterprise Application Architecture from bn.com. Slashdot welcomes readers' book reviews -- to see your own review here, read the book review guidelines, then visit the submission page.

16 of 94 comments (clear)

  1. Just Started but.... by RobTheJedi · · Score: 3, Informative

    I have just started reading this book, but so far I have found it to be very interesting as this is my first venture into the world of patterns. I found his discussion of "Business Ill-logic" very appropriate to most of the systems I have worked on.

    --
    I am so creative, look at my cry for attention in my sig.
  2. So. Cal. study group going through this book now by shodson · · Score: 5, Informative

    We have a design patterns study group that meets in Santa Ana twice a month to study this book. If anybody in the SoCal/Orange County area of California wish to join us please visit our website for more information.

    http://groups.yahoo.com/group/ocpatterns/

  3. Nylon bookmark? by shodson · · Score: 5, Funny

    BTW, my book didn't come with a nylon bookmark. That would have been useful. My GoF patterns book has a book marker. I think the use of embedded book markers and hard-bound covers are an attempt to represent the book as more cannonical, a biblical tech reference of sorts. Quite a few of the Addison Wesley books seem to follow this model, like GoF, as well as my 3 volume "TCP/IP Ilustrated" books.

  4. Review is as brief as the code "samples" by binaryDigit · · Score: 5, Insightful

    Hmm, this review lacks meat. The book is about patterns and the reviewer says the author has good ones. Well how about some examples of these patterns, esp one or two that are non trivial (and thus make having a book like this worthwhile). Since this book is obviously geared towards those with a fairly good level of experience/knowledge, that audience would want to see some real meat in the review, vs "it has good stuff, trust me". And no, a book that states "separate presentation and domain logic" does not automatically qualify it as a good book as this is "Programming 101" stuff.

    1. Re:Review is as brief as the code "samples" by jackbang · · Score: 5, Informative

      Try the book's site for a complete list of patterns, with diagrams and descriptions: http://www.martinfowler.com/eaaCatalog/

  5. Looks good... by Coz · · Score: 5, Informative

    I bought this last weekend, and it looks good. I'm seeing a lot of patterns I'd noticed, and he's brought up some that I can look back and say "Yeah, we did that - badly...."

    He does a good job talking about the pragmatic decisions that real architects and senior developers make, as opposed to the idealists and purists. The OO purists may want each attribute's "get" to be a separate call (and maybe cause that call to traverse the network), but the Remote Facade builds much more efficient interfaces. I've been building Domain Models and Foreign Key Mappings for years, and calling them by terms close to those.

    One of the things all these Patterns books have done is define a common terminology for concepts we've all known about. For that, if nothing else, we owe Fowler our thanks.

    --
    I love vegetarians - some of my favorite foods are vegetarians.
    1. Re:Looks good... by iav8c177s · · Score: 5, Informative
      That of course is a large part of the justification for design patterns in the first place -- giving us a common language.

      Fowler's book got a Productivity Award at this year's Jolts -- only reason he didn't get the Jolt, IMHO (OK, not so humble, I was one of the judges), is that Bob Martin's book was a little more fun to read and a little more generally applicable. (That one, BTW, is Agile Software Development: Principles, Patterns, and Practices).

      I can highly recommend either book.

  6. Martin Fowler Books by under_score · · Score: 4, Informative

    I am in the process of reading PoEAA - I agree wholeheartedly with the review. As a professional software architect and mentor, I often recommend Fowler's books. Another great one is "Refactoring" which presents a systematic method for improving the design of existing code.

    I have a list of excellent resources for software developers, architects, project managers, executives, etc.

    1. Re:Martin Fowler Books by dsplat · · Score: 3, Informative
      Another great one is "Refactoring" which presents a systematic method for improving the design of existing code.


      I have to second your recommendation of Refactoring. I feel the same way about it that I do about Design Patterns. Nearly everything in it is obvious ... while you are reading it. Those two books are references for the details that are easy to forget. Refactoring also builds more complex refactorings upon the base of the simpler ones. As that started to happen partway through the book, I started to see the true expressive power of referring to specific refactorings as a tool for abstraction ... very much like design patterns. This is all about building new layers of abstraction in ways that are easily manipulated.
      --
      The net will not be what we demand, but what we make it. Build it well.
  7. How does it compare by bmongar · · Score: 3, Interesting

    My question is how does it compare to the "gang of 4" Design Patterns book (ISBN 0201633612). It is a fairly complete catalog of patterns.
    I did notice that Fowlers book has code examples in Java, but I didn't find that code was important in describing patterns.

    --
    As x approaches total apathy I couldn't care less.
  8. Typos by glitch_ · · Score: 4, Informative

    Maybe I was the only one who noticed it, but the book is riddled with typos and grammatical mistakes that really make the information hard to absorb. Other than that, the book is very good and I recommend it highly.

  9. The ultimate enterprise pattern by DailyGrind · · Score: 5, Funny

    1) Purchase an enterprise pattern book
    2) Skim it and learn the jargon
    3) Repeat jargon to anyone who will listen until the powers that be put you in charge of a really large project
    4) Keep promising success until 80% of the effort is expanded
    5) Change jobs
    6) Go to 1)

    --
    You will have to pry my proprietary software $$$ from my cold dead hands!
  10. The patterns are available at the author's website by Anonymous Coward · · Score: 5, Informative

    http://www.martinfowler.com/eaaCatalog/

  11. Sounds like a good strategy re: code by dmorin · · Score: 3, Interesting
    I know that the value of printed texts, to me, decreased when we started including CDs with every book (or downloads for every magazine). Why? Because when all you're doing is running somebody else's code, usually without even looking at the source, you never get a chance to internalize it. You never have to say "What's this and why does it do that?" other than to answer "Because that's what the author chose to do and it's supposed to work like that." Back in the old days when you actually had to type code in, every line of the source went from print to eyes to brain to fingers. So whether you knew it or not you got a flow for what was going on. And you saw parts that interested you that you could come back to.

    These days code is so big that this is unfeasible. So it seems like Fowler has chosen an interesting strategy -- give you most of it. That way you still have to get into the editor and experience the source, but you don't have to spend days in order to do it. Nice. Learn by doing at its finest.

  12. Good Stuff by the-dude-man · · Score: 5, Interesting

    Books that will rant on at lenght about the technical details about languages like java and c# are a dime a dozen.What is lacking is good books that solidly illustate the patterns behind object oriented design.

    I think the reviews critisim about using such concepts as extending and implemeting in excess is not warrented, the book is about Objected oriented design, there are other ways to implement these methods, however, implementation of interfaces, and extending other classes, is really *the* object oriented way to solve this problem. Its hardly fair to say that its merly one way to solve the problem. There are many ways to implement the concept of extending another class or implementing an interface, however, these are technical details, and the primary focus of the book is patterns, and design principles, and wich ones work, and wich ones dont.

    Also, the other speaks of the lacking of code samples, agian, this is not a codeing book, the focus here is design, and principles. Therefore, code takes a back seat. The problem with putting code in books, is that you get bogged down by implementation details, wich really goes outside of the scope of what the author is talking about, with short code samples, the point can be convayed. How to implement it in a more complex situation in a particular language is the job of the individual devloper. This book obviously isnt going to get into it, because its about design.

  13. Re:"Enterprise" I'm sick of this word by geekoid · · Score: 3, Insightful

    enterprise imkplies a certian size and expected reliability.
    Business software is specific to a task, not the size of the tsck.

    Example:
    A database that can handle 100,000 transactions an hour, with 99.999 up time is 'enterprise' level.

    an application that tells you what is in your warehouse, business software. If that same software was called enterprise, you would expected it to have 99.999 uptime, and track many thousands, if not millions, of pieces of inventory scattered in warehouses around the globe.

    this is why I laugh when Microsoft calls SQLserver 'Enterprse ready'. it is not.

    --
    The Kruger Dunning explains most post on /. http://en.wikipedia.org/wiki/Dunning%E2%80%93Kruger_effect