MIDP 2.0 Style Guide for J2ME

nut writes "MIDP 2.0 is the latest version of the most common J2ME Profile. It comprises the Java Connected Limited Device Configuration (Usually referred to just as the CLDC) and a Java API for handheld wireless devices -- i.e. mobile phones, PDAs, etc. The MIDP 2.0 Style Guide for the Java 2 Platform, Micro Edition is one of a class of books that every application developer should read, and that not enough do, much like Nielsen's classic Designing Web Usability. It provides cheap access to knowledge that is expensive to obtain. The title is almost a misnomer; Call it a usability guide and give a better idea of its usefulness." Read on for the rest of nut's review. MIDP 2.0 Style Guide for the Java 2 Platform, Micro Edition author Cynthia Bloch, Annet Wagner pages 260 pages approx. publisher Addison Wesley rating 8 reviewer nut ISBN 0321198018 summary A comprehensive guide to usability in MIDP 2.0 programming.

MIDP 2.0 is also a fairly new specification -- in fact, the final release only came out in November of last year. Some phone and handheld manufacturers are already supporting it, however. Nokia, for example, have announced support for MIDP 2.0 on their Series 60 devices quite recently, and I would be very surprised if the competition hangs back in the wake of the success of the MIDP 1.0 specification.

A lot of the content in this book can be usefully applied to the many MIDP 1.0 devices. There is in fact a MIDP 1.0 style guide, now available online, but I would still recommend this book for the wealth of extra content that it has.

The MIDP 2.0 Style Guide is a widget-by-widget guide to best-practice programming with the MIDP 2.0 API. The information contained within comes from established design principles, J2ME programming and implementation experience, and usability studies. Usability studies, especially, don't come cheap. Such labour-intensive research is well out of the reach of most individual programmers and small companies, so there is real value for money here.

The layout is very browseable, with most of the sixteen chapters each being a set of recommendations for a specific widget such as a text box or a gauge. The first three chapters (this includes the introduction) are more concerned with defining the goals of the book, the technology it relates to and the bones of a user-interface design process. For the most part, each chapter follows a standard format that is defined in the introduction.

Some of the later chapters cover topics that have less to do with user interface design, such as application installation and management, and the security API. The table of contents is comprehensive, listing not only chapters but two layers of headings within chapters -- useful in a reference book.

There are two target audiences here: J2ME developers and MIDP 2.0 implementors. For the former, it's an excellent resource. For the latter, I would say it was required reading. This is because it ends up defining what amounts to a contract between MIDP implementors and application developers.

For instance, from two successive recommendations on text boxes:

Application Developers
"Use [The NON_PREDICTIVE] modifier in a textbox that has a URL, EMAIL, NUMERIC, or DECIMAL constraint. Email addresses and domain names are not typical words, so turning off predictive text input ..."

And in the next paragraph,

MIDP Implementors
"If the application specifies the NON_PREDICTIVE modifier, allow users to enter one character at a time without any predictive input facilities."

Clearly the first recommendation is only meaningful if the second has been followed already. There are lot of these sort of co-dependent recommendations, covering areas such as default actions for abstract commands, list selection defaults, field constraints, etc.

There is still a lot of slop in the MIDP 2.0 specification. Its scope is, after all, fairly broad -- encompassing forms and form widgets, graphics canvases, game canvases and sprites, command design patterns, messaging and networking, security and application delivery APIs. Besides which, large chunks of the spec are optional, or can be implemented in more than one way. In part this is to preserve backward compatibility with MIDP 1.0, but it also means that your UDP-based streaming video application might work on only some the devices that support the same standard.

This looseness is only to be expected in such a young technology, but it means that books such as this may help to define the standard if people use the recommendations they provide. I would expect many of the recommendations in here to become part of future versions of the MIDP specification.

NOTES:
For more information on J2ME in general, and MIDP in particular, I also recommend Programming Wireless Devices with the Java 2 Platform, Micro edition [2nd ed.] and, of course, there are all the specifications and tutorials at Sun's Java site.

The J2ME Wireless Toolkits versions 1.0.x and 2.0 are good starting points for development as well. Version 2.0 of the wireless toolkit supports MIDP 2.0.

You can purchase MIDP 2.0 Style Guide for the Java 2 Platform, Micro Edition from bn.com. Slashdot welcomes readers' book reviews -- to see your own review here, read the book review guidelines, then visit the submission page.