9 Internet and Distributed Application Development,
by William Green and John D. Olson, ISBN 0-672-32499-7
to the web site
9 with EAServer, iAnywhere m-Business Studio and Sybase
It is exciting to see a book dedicated to Internet
and Distributed Application Development using PowerBuilder.
If you scan the book quickly, you'll find a lot of
text discussing EAServer rather than PowerBuilder
and many readers may have already turned away from
the book that reason. However it's a misconception
carried over from the client/server role of PowerBuilder
that it has to play a prominent role in the application
development process. This is no longer true in the
distributed or web development where many components
play their roles in harmony.
What's the role of PowerBuilder in Internet and
Distributed Application Development? The book does
not provide a straightforward answer to this question.
However, one can summarize from various chapters
as the follows: (1) Create Web Datawindows (chapter
7); (2) Import and export XML datawindows (chapter
8, 20); (3) Create objects for deployment to EAServer
(chapter 5, 9); (4) Create proxy and call web services
(chapter 21); (5) Create EJB proxy to access EJB
servers (chapter 23). One unlikely role mentioned
in the book (and not fully explained) is to create
PowerBuilder objects wrapped for other servers.
As discussed in chapter 4, it is a question whether
to migrate PowerBuilder applications or to rewrite
in Java. From the business point of view, it makes
sense to do incremental rewrites rather than full
rewrites of existing applications. During the transition
period, PowerBuilder is still valuable as a rapid
development tool to interface with other platforms.
Unless Java comes up with a rapid development framework,
it is impossible for Java to replace PowerBuilder
in the business world. It is also obvious that PowerBuilder
will be more and more restricted in terms of its
accessibility to the database servers. PowerBuilder
has to operate through application servers or web
servers in the distributed world. From this book,
it is also apparent that Sybase will not make PowerBuilder
function as an application server or web server.
Aside from the PowerBuilder discussion, the book is full
of EAServer configuration and troubleshooting guides. However,
this is not an EAServer book. If you expect a systematic
guide to EAServer, you'll be disappointed. For someone
who already has experience running EAServer however, this
is still an informative book. Chapter 3 is an overview,
chapter 12 deals with EAServer multithreading, chapter
15 on Deployment, and chapters 16 to 19 are about EAServer
administration, monitoring and caching.
The most exciting chapter in this book is the one on mobile
systems (chapter 22). Berndt Hamboeck does an excellent
job of describing the background of mobile computing and
shows you how to create a WAP page. He also discusses Sybase
iAnywhere m-Business System and Enterprise Portal. The
SQL features are also intriguing. Other chapters on distributed
computing (chapters 1, 2, 6), application migration (chapter
4), web services (chapter 21), and EJB (chapter 23) are
well written and very informative too.
If there is
any shortcoming to this book, it is the organization
of topics that sometimes require readers to jump between
chapters. XML datawindows is discussed (chapter 8) before
the XML development (chapter 20). The same topic "What
is XML" is duplicated in both chapters 8 and 20. It
is interesting that chapter 8 states that "... are
discussed in detail in the book's sister publication: PowerBuilder
Internet and Distributed Application Development (Sams
Publishing, 2003), by William Green and John D. Olson," which
is this book! The chapter on web services mentions a companion
CD with Apache axis, but there is no companion CD supplied
with the book.
This is the most up-to-date PowerBuilder companion on
distributed and web development so far. The authors have
put together an informative volume that should be helpful
for PowerBuilder developers and any other web developers.
The power of EAServer is demonstrated in many places in
the book. IT managers who read some of the chapters may
change their view of the next phase of application migration
or rewrites. Readers who have been disappointed by a cursory
skim of the book should re-read it in order to discover
its hidden treasures. Recommended.
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