Application of design patterns for the self-development of a Java preprocessor

An application of design patterns in the domain of language processing is presented. The target of the paper is a Java preprocessor which enables one, not only to add new features to the Java language but also to rewrite existing Java programs. Making use of several design patterns, including Reflection Architectural Pattern, we successfully create a framework for language processing in Java. In particular we design and implement a core language extension of Java so that self development and maintenance of the framework are possible. Several applications of the Java preprocessor and the framework are described, which include enumeration type definition, method tracer, and generic type definition mechanism.