Primary Implementation Of XL Web Service Platform

Current, web services are very popular and corresponding technologies appear one after another (e.g. SOAP, UDDI, XLANG, WSFL). While all these technologies greatly accelerate the development of web services, they constantly put forward new challenges. The programming language used to develop current web services are almost traditional programming language (e.g. java, c#). They are powerful, but they can't enable the Web Services to achieve high scalability, security and availability, and to increase application developers' productivity. In order to solve above problems in a certain degree, this article describe a new programming language designed for the implementation of Web Services—XL Language(XL) which was proposed by Danida Florescu. Based on the representation of XML Language, this article describes the steps and key technologies of implementation of this new programming language.XL is designed for the implementation of Web services. XL is portable and fully compliant with W3C standards such as XQuery, XML protocol, and XML Schema. One of the key features of XL is that it allows programmers to concentrate on the logic of their application instead of low-level things such as communication protocol and data integration. XL provides high-level and declarative constructs for actions which are typically carried out in the implementation of a Web service; e.g., logging, error handling, workload management, events etc. Issues such as performance tuning(e.g., caching, horizontal partitioning, etc.) also are carried out automatically by an implementation of the language. This way, the productivity of the programmers, the ability of evolution of the programs, and the chances to achieve good performance are substantially enhanced.After the syntax and semantics of XL are described, its architecture is proposed. The architecture is based on the query engine of XQuery and it is composed of XL-Compiler and XL-virtual machine. The article presents the detailed analysis of key parts in XL-Compiler and XL-virtual machine, such as syntax tree , context etc.On the ground of above theories, a platform which compiles and run XL is primarily implemented by Java. As an attempt, syntax tree and statement tree are represented by XML; service is designed by the way of Servlet; the way of execution of XL is the way which XML documents are interpreted and executed.The specification of XL is just the first version and has a lot of faultiness, The platform implemented by java is also just a elementary and coarse model. There are a lot of works to do. So at the end of this article, related further works are discussed.