UBC Theses and Dissertations
Doxpects : XML transformation aspects Minevskiy, Ivan
Web services in the context of an Enterprise Service Bus provide an architectural approach to decomposing IT solutions into reusable pieces readily responsive to changing business demands. Developing a web service involves working with two different primary decompositions: the object-oriented design and the XML document structure. XML message transformations, such as encryption and adaptation, often manifest as crosscutting concerns. Some existing middleware standards address such document-oriented concerns by allowing custom Handlers to intercept and transform XML messages at various times during a service invocation. However, handlers do not support the sound software-engineering principle of "programming to an interface". Their coarse-grained interface makes it difficult to map the design of concerns to the implementation and prevents useful static checking by a language compiler (e.g. checking whether two handlers may perform conflicting actions). To address this and similar design challenges, we have developed a new programming model, called Doxpects, which simplifies the development and maintenance of Handlers. The main benefit of Doxpects is the ability to perform XML document transformation tasks (insertion, deletion, and replacement) in a familiar object-oriented way. Doxpects enable fine-grained statically-typed handler interfaces and take advantage of them.
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