Scripting Refactorings in Java to Introduce Design Patterns

TL;DR: Reflective Refactoring (R 2) is presented, a Java package to automate the introduction of classical design patterns (Visitor, Abstract Factory, etc), their inverses and variants, and why refactoring speed and correctness are critical issues for scripting in next-generation refactororing engines.

Abstract: Introducing design patterns into a program by hand is tedious and error-prone. Refactorings help but manual tasks still remain: you must understand available refactorings, determine a precise sequence of refactorings to invoke, and perform these tasks repetitively to a laborious degree. We present Reflective Refactoring (R 2 ), a Java package to automate the introduction of classical design patterns (Visitor, Abstract Factory, etc), their inverses and variants. We encoded 78% of classical design patterns asR 2 scripts. In one application,R 2 automatically created a visitor with 276 visit methods by invoking 554 Eclipse refactorings in a few minutes ‐ an achievement that could not be done manually. We demonstrate the generality and scalability ofR 2 , illustrate its productivity potential, and explain why refactoring speed and correctness are critical issues for scripting in next-generation refactoring engines.