The Study On Transcoding Technology Of Extensible Markup Language Oriented To Wireless Environment

In recent years, with the continual increase of the demands and markets on wireless application, people access Internet with cellular phone becomes increasingly popular, both the business of wireless application and WAP devices have got more and more attention. However, because of the protocol and markup language used by the WAP devices is not the one used in Internet, WAP devices can't visit the Internet directly. To resolve of this problem, we need to implement two types of transformations, i.e., protocol transformation and transcoding of markup language.Based on the deep study of current traditional transcoding technical of markup languages, we put forward an auto-driven transcoding technique, which transforms the extensible Markup Language (XML) used in the Internet to the markup language used by WAP devices automatically.Firstly, we analyzed three key techniques: (1) adapting variability of the user and the devices; (2) analyzing the source document automatically; (3) building the style-sheet automatically.Secondly, we gave the implementing methods for the above three key techniques. In allusion to the first key technique, we built up a file system of devices profile, and picked up the identifier of the device from the protocol message. Then, we used the identifier to access the file system so to obtained properties of the device. In allusion to the secondly key technique, we used the DOM method to analyze source document and acquired the structure of the source document. By the metod, we can get the classification of the node in the DOM tree. The node in DOM tree is the foundation of style-sheet. In allusion to the last key technique, we proposed the idea of converting the unsymmetrical transcoding to the symmetry transcoding. We built the homologous XSLT template for all types of the node in DOM tree. Then, after the types of the nodes in an actual XML document have been obtained by DOM analysis, we can build the actual XSLT document correspond with the source document, and use this XSLT document for transcoding.The paper studied the expansibility of the auto-driven transcoding technique and proved that the problem could be resolved by the plug-in technique. And for the sake of the efficiency, the paper discussed the reusability of the style-sheet, and put forward a method so to build a reusable style-sheet.The paper compared the auto-driven transcoding technique with the traditionaltranscoding techniques. Our technique can provide the proper XSLT document according to the properties of the device and the structure of the source document, and our method manifested itself with more efficiency and more expansibility.Finally, the paper summarized our main works and described our future directions.