Dr. Dobb's Journal - July 2008 - (Page 32)

Core Technology GRAPHS VERSUS OBJECTS continued from page 30 How does Web 2.0 impact these attributes? Web 2.0 represents three significant trends: scale, change, and integration. Web 2.0 has evolved the emphasis on systems—they must scale rapidly, quickly adapt to new possibilities, and easily integrate with others. Thus to be Web 2.0 enabled, you must carefully consider how your development choices incorporate these Web 2.0 trends. Additionally, the intelligence of your program becomes even more of a key asset—you no longer JPEG 2000 JPIP, 3D, AND TRANSCODING IMAGE COMPRESSION LIBRARIES · Powerful low-level C libraries · 64-bit & 32-bit, on multiple platforms · Optimized for multiple cores · Lossless and lossy mode · Compressed image optimization for JPIP · Compress to PSNR value or file size · Codestream and file format support · Control progression order, precinct sizes, and tile sizes DOWNLOAD A FULL-FEATURED TRIAL VERSION OF THE PICTOOLS SDK TODAY. Supported across: Microsoft® Windows® LINUX must do everything from moving data bits to a fancy GUI. If you can incorporate the trends into your solution, many Web 2.0 possibilities are already there for your integration. You can then focus on what you do best—your smarts. Now let’s examine some code examples that highlight the differences between objects and graphs. The complete code example is available online at SemWebCentral (www.SemWebCentral.org) and from DDJ; see “Resource Center,” page 3. We selected a well-understood and completely original programming application—the digital marketplace. We also introduce changes as we build out the application. Two complete solutions are presented: object based and graph based. We start with the object based. The code highlights five major aspects, such as how to: • • • • • Represent knowledge Create instances of knowledge Integrate knowledge Interrogate knowledge Change the representation The better the representation, the better the semantics, but it must be able to work efficiently within the real-world constraints. Objects Of My Affection 2008 seems a good time to experiment with a truly futuristic idea—an online store! First, we’ll need sellers and buyers (using a Person class with a name field) with something to sell and purchase. Figure 1, the object-oriented UML class diagram for our example, depicts the knowledge representation. Here we declare the representation in Java. Note the mixture of representation with actual processing. As the complexity grows, this becomes difficult to separate and improve. We use line numbers to denote that the following is an abridged code version: 3 public class PurchasableItem { 5 private float cost; 6 private String manufacturer, label; Sun® Solaris IBM® AIX® Contact us for more information. W W W . P E G A S U S I M A G I N G . C O M Pegasus is a registered trademark of Pegasus Imaging Corporation in the United States. The names of actual companies and products mentioned herein may be the trademarks of their respective owners. 32 Dr. Dobb’s Journal l www.ddj.com l July 2008 http://www.SemWebCentral.org http://www.pegasusimaging.com http://www.ddj.com

Table of Contents Feed for the Digital Edition of Dr. Dobb's Journal - July 2008

Dr. Dobb's Journal - July 2008 Contents Friday Night Fish Fry Alia Vox Developer Diaries Developer’s Notebook Engineers Without Borders Conversations Patricia Tries Event-Based Architectures Graphs Versus Objects Lock-Free Queues Dr. Dobb’s Architecture & Design World Java and the Nokia N10 Internet Tablet Effective Concurrency The Agile Edge Swaine’s Flames

Dr. Dobb's Journal - July 2008

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