Clearwater: An Extensible, Pliable, and Customizable Approach to Code Generation

Since the advent of RPC Stub Generator, software tools that translate a high level specification into executable programs have been instrumental in facilitating the development of distributed software systems. Developers write programs at a high level abstraction with high readability and reduced initial development cost. However, existing approaches to building code generation tools for such systems have difficulties evolving these tools to meet challenges of new standards, new platforms and languages, or changing product scopes, resulting in generator tools with limited lifespan. The difficulties in evolving generator tools can be characterized as a combination of three challenges that appear inherently difficult to solve simultaneously: the abstraction mapping challenge translating a high-level abstraction into a low-level implementation), the interoperable heterogeneity challenge stemming from multiple input and output formats, and the flexible customization challenge to extend base functionality for evolution or new applications. The Clearwater approach to code generation uses XML-based technologies and software tools to resolve these three challenges with three important code generation features: specification extensibility, whereby an existing specification format can accommodate extensions or variations at low cost; generator pliability, which allows the generator to operator on an extensible specification and/or support multiple and new platforms; and flexible customization, which allows an application developer to make controlled changes to the output of a code generator to support application-specific goals. The presentation will outline the Clearwater approach and apply it to meet the above three challenges in two domain areas. The first area is information flow applications (e.g., multimedia streaming and event processing), a horizontal domain in which the ISG code generator creates QoS-customized communication code using the Infopipe abstraction and specification language. The second area is enterprise application staging (e.g., complex N-tier distributed applications), a vertical domain in which the Mulini code generator creates multiple types of source code supporting automatic staging of distributed heterogeneous applications in a data center environment. The success of applying Clearwater to these domains shows the effectiveness of our approach.Ph.D.Committee Chair: Calton Pu; Committee Member: Donald F. Ferguson; Committee Member: Karsten Schwan; Committee Member: Ling Liu; Committee Member: Olin Shiver

ACKNOWLEDGEMENTS

One of the most wonderful, extraordinary qualities of a computer program is its synthesis of ideas from many sources into a useful, operational whole. To a certain degree, I think of a computer program as a bit like a knowledge machine in which every programmer and every designer create the patterns and parts that comprise the whole. Perhaps not too surprisingly, just as computer programmers often must sledge, hone, and burnish our ideas into the precision-fit final design, so too do many take part in the creation of a neo-Ph.D. Of my family, I wish to thank both my wife and my parents. My wife, Melissa, has had the fortitude, good nature, and stamina to keep me on track, to cheer me on when my motivation might flag. I thank her for that and hope I can re-pay her patience. My parents, too, were invaluable in their support, but more importantly, they set me on the path to achieve this Ph.D. – a concerted 29-year effort. I thank them for their guidance and motivation to move down the path to the highest education. Calton, my advisor, is also key to my success as a student. Without his vision and perception, I might very well have labored in these gold mines without producing a