Eliminating redundancies with a "composition with adaptation" meta-programming technique

Abstract

Redundant code obstructs program understanding and contributes to high maintenance costs. While most experts agree on that, opinions -on how serious the problem of redundancies really is and how to tackle it -differ. In this paper, we present the study of redundancies in the Java Buffer library, JDK 1.4.1, which was recently released by Sun. We found that at least 68% of code in the Buffer library is redundant in the sense that it recurs in many classes in the same or slightly modified form. We effectively eliminated that 68% of code at the meta-level using a technique based on "composition with adaptation" called XVCL. We argue that such a program solution is easier to maintain than buffer classes with redundant code. In this experiment, we have designed our meta-representation so that we could produce buffer classes in exactly the same form as they appear in the original Buffer library. While we have been tempted to re-design the buffer classes, we chose not to do so, in order to allow for the seamless integration of the XVCL solution into contemporary programming methodologies and systems. This decision has not affected the essential results reported in this paper.

Query-based filtering and graphical view generation for clone analysis

“…StrutsBox is an Eclipse [7] plug-in for developing applications with Apache Struts Framework (http://struts.apache.org/). Its central component is a visual editor that graphically shows the flow of information in web applications.…”

“…Its central component is a visual editor that graphically shows the flow of information in web applications. Apache Struts is an open source framework for developing Java Web Application [7]. It uses MVC (Model -View -Controller) architecture (http://en.wikipedia.org/ wiki/Model-view-controller), where Model represents the business logic, View represents the user-interface, and Controller represents the navigational code.…”

“…Knowledge of clones may also shed light on the quality, maintainability and reusability of a software system, and can help in software reengineering. Some of the clones can be unified by applying design patterns, refactoring, using macros or a generative technique such as Aspect-Oriented Programming (AOP) [15] or XML-based Variant Configuration Language (XVCL) [22] [7] [23]. The above observations motivate work on clone detection and analysis.…”

Project-driven university-industry collaboration

“…In our studies of new, well-designed programs, we typically found 50%-90% of code contained in such similar program structures, repeated many times (often called clones in the literature). For example, the extent of the redundant code in Java Buffer library was 68% [6], in parts of STL (C++) -over 50% [1], in J2EE Web Portals -61% [12], and in certain ASP Web portal modules -up to 90% [9]. The last two results are from the projects at STEE in which XVCL was applied to combat the problem of counterproductive repetitions.…”

Beyond templates

“…Code clones often hint at the existence of design-level similarity patterns in a program (or across programs). Such large granularity similarity patterns -we call them "structural clones" -signify reuse opportunities that, if properly exploited, could lead to simpler, easier to maintain, and more reusable program solutions [19]. The reasons why clones appear in source code have been analyzed [6][14] [20] and clone detection tools have been proposed [1] [6][14] [21].…”