Programming Java 2 Micro Edition for Symbian OS 2004 (779882), страница 2
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We then concentrate on programming MIDPand the additional APIs that make up the Java platform on the latestgeneration of Symbian OS phones.Section 2 investigates design and implementation considerations involved in writing high-quality code, focusing on the issues of portabilityand efficiency.The final section looks at the strategic importance of Java to the wirelessecosystem and provides a glimpse as to how Wireless Java may evolveon Symbian OS.Who Is This Book For?The book is aimed at Java developers already programming in thewireless space or interested in moving into the wireless space and whowish to know what can be achieved with J2ME on the latest SymbianOS phones. Enough introductory information and examples are providedfor newcomers to J2ME to get going with MIDP programming, while thethorough treatment of the new MIDP 2.0 and optional APIs provides moreweighty fare for the experienced MIDP programmer.ABOUT THIS BOOKxiConventionsTo help you get the most from the text and keep track of what’s happening,we’ve used a number of simple conventions throughout this book.When we refer to words you use in your code, such as classes,attributes and methods, or to the name of a file, we use this style:Person class: we obtain the name attribute by invoking the getNamemethod on our Person instanceWhen we list code, or the contents of files, we use the following convention:SocketConnection conn = (SocketConnection)Connector.open(url);DataOutputStream out = conn.openDataOutputStream();byte[] buf= request.getBytes();out.write(buf);out.flush();out.close();We show commands typed at the command line like this:C:\WTK20\apps\Example\src>javac -d tmpclasses -bootclasspath %MIDPAPI%-classpath %J2MECLASSPATH% *.javaURLs are written: www.symbian.com/developerAuthor BiographiesMartin de JodeMartin graduated from the University of York with a BSc in Physics and,after a brief spell in industry, returned to academia to undertake researchin the field of non-linear optics at Essex University.
Graduating with aPhD, Martin spent eight years working in research at the London HospitalMedical College, studying the use of lasers to treat cancer. During thistime he developed a particular interest in using Monte Carlo simulationto model the interaction of light with biological tissue using Fortran.Martin joined Symbian in 2000, after completing an MSc in ObjectOriented Software Systems from City University.
As a Java DeveloperConsultant in Symbian’s Developer Network he spends his time providingsupport to Symbian’s Java developer community. In addition to writingtechnical papers on PersonalJava and J2ME for Symbian’s website, Martinhas developed numerous utility and sample applications showing howto make the most of Symbian’s Java platform. Other activities includedelivering training, evangelizing Java on Symbian OS and trying to keepup with the proliferation of J2ME JSRs.Outside of work, Martin is passionate about cricket, having spent whatseems like a lifetime playing competitive club cricket in and around thehome counties.Jonathan AllinJonathan is Symbian’s Product Manager for Java Technology.
His roleis to ensure that Symbian OS provides a first class Java platform formobile phones, and covers Symbian’s Java strategy and implementationroadmap, partnerships, and, of course, how Java relates to other development environments. Jonathan was the lead author of Wireless Javafor Symbian Devices, authored the ‘‘Developing with Java’’ chapter inxivAUTHOR BIOGRAPHIESProfessional Symbian Programming, and presents regularly on wirelessJava opportunities and optimizing Java code for mobile devices.Jonathan has a BSc in Electronics and a DSc in Biomedical Engineering.He picked up an MBA when working for Acorn Computers, where hehelped develop computers and software for schools.
Prior to joiningSymbian in 1999, he worked for Origin BV for three years, where hefirst became interested in Java and particularly the role it can play withinthe enterprise.Jonathan is married to Lauren, who is a social worker and essential forkeeping in order their three children: Benjamin, Daniel, and Victoria, whoare into rugby, music, and hockey respectively. Java reminds Jonathanthat computing can be fun, interesting and useful.Darren HollandDarren joined Symbian in 2002. He graduated in 1995 with a BScin Computing Systems Technology and started his career developingtelephone billing and enterprise fax software in C++ before starting towork with Java in 1999.Darren would like to thank the IS department of Symbian who provided support throughout the development of the Expense applicationprototype, ensuring that the resources and infrastructure required were inplace.
More importantly, they supported the project remit and suppliedthe encouragement that ultimately ensured success. In particular OliviaHawkins, Belen Ares Paredes and Tarek Meliti contributed greatly.Darren would also like to thank his wife Solène for her continualsupport and for helping to keep him sane during life’s more stressfulmoments. No matter how much Darren enjoys work he would alwaysrather be sailing!Alan NewmanAlan Newman is a technology consultant and freelance technical writer,living in Brighton with his partner Abi and his son, Freddie, who was bornin the summer of 2003.
He has been programming since he was 8 yearsold when he acquired his first computer, a Sinclair ZX81, before movingon to the Commodore Pet, and BBC B Micro.After graduating with a business degree, he began working in the NHSas an analyst, automating many previously manual data entry tasks forhis department. He then moved into banking and programmed tradeentry and loan collateral management systems on the trade floor ofthe Republic National Bank of New York where, in 1998, he took akeen interest in learning Java and its interaction with the Internet.
HeAUTHOR BIOGRAPHIESxvthen spent a year with Internet sports magazine Sportal.com, beforesetting up his own company, Sensible Development, which created andnow runs a multiplayer football manager game, which can be found atwww.effeffelle.com.He is an advocate of plain speaking as a means of preventing thatglazed-over look consumers often show when confronted with technology. He also believes that technology should not dictate but insteadenhance consumer and business tasks.Colin TurfusColin graduated from the University of Dundee, Scotland with a BSc(Hons) in maths and physics, and from the University of Cambridgewith a PhD in applied mathematics.
He has researched and lectured atuniversities in the UK and in South Korea, publishing papers in fluiddynamics and computational astrophysics. He became interested in Javaprogramming while developing intranet-based maths teaching resourcesand lecturing about Internet technology in South Korea.He joined Symbian shortly after its inception in the summer of 1998,and has been involved since in establishing and building the SymbianDeveloper Network, which he now heads.
He was a contributing authorto Wireless Java for Symbian Devices.Colin’s interests include jogging, hill-walking and classical guitar. Heis married to Keum-ye from South Korea. They have three girls: Selina,Sonya and Emily.Author’s AcknowledgementsFirst and foremost I would like to thank my co-authors Alan Newman,Jonathan Allin, Colin Turfus and Darren Holland without whose help wewould not have been able to create this book.I must also thank Phil Northam of Symbian Press, whose initial ideathis book was and who lobbied hard for its realization.
Also thanks to hisassistant Freddie Gjertsen for his painstaking work in ensuring consistencyin the style and grammar of our work and who kept us all on the straightand narrow.I’m also very indebted to the reviewers from Symbian’s Java Engineering team: Hana Bisada, Roy Hayun, Simon Lewis, Michael Aubert, IvanLitovski and George Sewell, the real experts, who develop Symbian’sJava implementation. They have all spent considerable time ensuring thecorrectness and quality of the author’s contributions.I’m grateful to the guys at Rococo Software for providing us with theirImpronto Simulator for JSR 82, and in particular to Steven Crane forsuggesting numerous improvements to Chapter 5.
I’d also like to thankJarmo Lahtinen and Janne Levula from Nokia for their advice on aspectsof the MIDP implementation running on the Nokia 6600.I would also like to extend my thanks to Gaynor Redvers-Mutton whohas ably managed the publication of the book at John Wiley.Last, but far from least, I must mention the Symbian work placementstudents Xi Chen and Sunny Khaila, who provided much of the groundwork for this book. As well as exploring the MIDP 2.0 specification, theyalso produced early prototypes of several of the example applicationsfeatured in the text.Symbian Press AcknowledgementsSymbian licenses, develops and supports Symbian OS, the platform fornext-generation data-enabled mobile phones.
Symbian is headquarteredin London, with offices worldwide. For more information see the Symbian website, www.symbian.com. ’Symbian’, ’Symbian OS’ and otherassociated Symbian marks are all trademarks of Symbian Ltd. Symbianacknowledges the trademark rights of all third parties referred to inthis material.Thanks to all who have had input into this book, including the manywhose behind-the-scenes work ensured the book was delivered on time!Let’s not forget the Laughing Gravy and the Stage Door either.
. .About the coverThe cover concept, designed by Jonathan Tastard, was inspired by DavidLevin, CEO of Symbian, in a 2003 keynote presentation at Exposium,where he pronounced:The mobile phone has traditionally connected the mouth to the ear.Symbian develops Symbian OS to enable a new generation of connectedcommunications devices to connect the mouth to the ear to the eye.To realize this vision, the mobile phone industry is working together todevelop the latest technologies, support open industry standards, and ensureinteroperability between advanced mobile phones as networks evolve from2.5G to 3G.ForewordTim Lindholm, Architect of the J2ME platform at Sun Microsystems, Inc.The rate of adoption of the Java platform in wireless devices is unprecedented, but more important is the change in perspective that theadoption reflects.The desktop and server have relatively long histories as open platformsand, as such, have evolved developer communities and vibrant marketsfor third-party software.
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