Protecting Legacy Applications from Unicode

While XML-based Web Service architectures are successfully turning the Web into an infrastructure for cooperating applications, not all problems with respect to interoperability problems have yet been solved. XML-based data exchange has the ability to carry the full Unicode character repertoire, which is approaching 100'000 characters. Many legacy application are being Web-Service-enabled rather than being re-built from scratch, and therefore still have the same limitations. A frequently seen limitation is the inability to handle the full Unicode character repertoire. We describe an architectural approach and a schema language to address this issue. The architectural approach proposes to establish validation as basic Web Service functionality, which should be built into a Web Services architecture rather than applications. Based on this vision of modular an infrastructure-based validation, we propose a schema language for character repertoire validation. Lessons learned from the first implementation and possible improvements of the schema language conclude the paper.