Exploring Remote Object Coherence in XMLWeb Services

Object-level coherence in distributed applications and systems has been studied extensively. Object coherence in platform-specific and tightly-coupled systems is achieved with binary serialization protocols to ensure data structures and object graphs are safely transmitted, manipulated, and stored. On the opposite side of the spectrum are platform-neutral Web services that embrace XML as a serialization protocol for building loosely coupled systems. The advantages of XML to connect heterogeneous systems are plenty, but rendering programming-language specific data structures and object graphs in text form incurs a performance hit and presents challenges for systems that require object coherence. Achieving the latter goal poses difficulties by a phenomenon that is sometimes referred to as the "impedance mismatch" between programming language data types and XML schema types. This paper examines the problem, debunks the O/X-mismatch controversy, and presents a mix of static/dynamic algorithms for accurate XML serialization. Experimental results show that the implementation in C/C++ is efficient and competitive to binary protocols. Application of the approach to other programming languages, such as Java, is also discussed