Compile-time Reflection and Metaprogramming for Java

Java reflection enables us to write reusable programs that are inde-pendent of certain classes. However, when runtime performance is a big concern, we propose to use compile-time reflection for writ-ing metaprograms that generate non-reflective class/type specific code, which has lower runtime cost. We proposed both compile-time reflection and metaprogram-ming for Java, and extended our previous work on pattern-based traits. Pattern-based traits integrate pattern-based reflection with flexible composition of traits. They are capable of pattern-matching over class members and generating expressive code. We add and formalize pattern-based reflection at the statement-level, which enables a meta program to generate statements. We add reified generics for pattern-based traits, which enables a pattern to iter-ate over any class when traits are instantiated. We implemented an ORM tool (called PtjORM) using pattern-based traits. PtjORM uses compile-time reflection and our benchmark tests show that it has competitive runtime performance compared to the mainstream Java ORM tools