一种基于模板的面向方面重构框架的研究

面向方面编程是一种新的编程范型,而面向方面重构则是当前面向方面软件开发中的一个研究热点。首先对面向方面重构进行了分类研究,然后引入基于角色的横切关注点重构方法,最后在此基础上提出一种基于模版的面向方面重构框架。     

Tool-Supported Refactoring of Existing Object-Oriented Code into Aspects

Aspect-oriented programming (AOP) provides mechanisms for the separation of crosscutting concerns - functionalities scattered through the system and tangled with the base code. Existing systems are a natural testbed for the AOP approach since they often contain several crosscutting concerns which could not be modularized using traditional programming constructs. This paper presents an automated approach to the problem of migrating systems developed according to the object-oriented programming (OOP) paradigm into aspect-oriented programming (AOP). A simple set of six refactorings has been defined to transform OOP to AOP and has been implemented in the AOP-migrator tool, an Eclipse plug-in. A set of enabling transformations from OOP to OOP complement the initial set of refactorings. The paper presents the results of four case studies, which use the approach to migrate selected crosscutting concerns from medium-sized Java programs (in the range of 10K to 40K lines of code) into equivalent programs in AspectJ. The case study results show the feasibility of the migration and indicate the importance of the enabling transformations as a preprocessing step     

面向方面的自动化重构方法

提出一种将面向对象程序重构为面向方面范型的自动化方法。该方法分挖掘和重构两个阶段进行。第一阶段挖掘面向对象程序中潜在的横切关注点,第二阶段将横切关注点重构为方面。给出一个约13 000行代码的程序自动重构的评价结果。     

基于AOP的面向对象程序的单元测试

单元测试被视为横切关注点,在软件测试过程中很重要。而面向方面编程(AOP)的主要目标就是分离横切关注点,因此,单元测试非常适合用AOP来解决。该文提出了在对面向对象程序进行单元测试时遇到的问题,并用AOP方法加以解决,同时比较了传统方法和AOP方法进行单元测试的优缺点。     

基于 UML扩展的面向方面建模 *

面向方面编程 ( AOP)把横切关注点从系统中分离 ,解决了面向对象编程 ( OOP)中代码纠缠、散射的问题。但在面向方面建模中 ,横切方面没有得到很好的支持。首先 ,在统一建模语言 ( UML)元模型的基础上利用类图建立了整体框架模型 ,设计了核心类、方面、横切元素及其之间的关系 ;其次 ,利用 UML扩展机制为切点、通知、方面等主要元素建立了新的模型 ,设计了它们与方面之间新的关联关系并为其定义了语义。通过 UML扩展,使得 UML能够直接表达面向方面概念 ,支持面向方面建模设计 ,实现了面向方面模型     

基于 UML扩展的面向方面建模 *

面向方面编程（AOP）把横切关注点从系统中分离,解决了面向对象编程（OOP）中代码纠缠、散射的问题。但在面向方面建模中,横切方面没有得到很好的支持。首先,在统一建模语言（UML）元模型的基础上利用类图建立了整体框架模型,设计了核心类、方面、横切元素及其之间的关系;其次,利用UML扩展机制为切点、通知、方面等主要元素建立了新的模型,设计了它们与方面之间新的关联关系并为其定义了语义。通过UML扩展,使得UML能够直接表达面向方面概念,支持面向方面建模设计,实现了面向方面模型的可视化和可辨别性;整体框架模型使得面向方面整体结构清晰,各个核心元素之间关系明确,为面向方面建模提供了一个整体设计平台,提高了面向方面软件设计的模块化,增强了代码的重用性和系统的可维护性。     

一种基于横切特征分析的软件体系结构自动重构方法

软件体系结构中的横切关注点增加了软件体系结构的复杂性,从而加剧了体系结构演化与维护的困难.这种设计问题可以通过体系结构层面的重构来进行改善.在已有的横切特征分析方法基础上,提出了一种面向横切特征分析的体系结构自动重构方法.该方法首先基于特征与构件之间的追踪关系分析横切特征,然后将与横切特征有直接追踪关系的构件从初始体系结构中提取出来,实现方面构件,完成体系结构重构.在面向方面体系结构描述语言AO-ADL基础上开发了相应的体系结构重构工具,并针对一个业务系统进行了体系结构重构实验.实验结果表明,该方法能有效地实现体系结构横切特征的自动化重构.     

Applying and combining three different aspect Mining Techniques

Understanding a software system at source-code level requires understanding the different concerns that it addresses, which in turn requires a way to identify these concerns in the source code. Whereas some concerns are explicitly represented by program entities (like classes, methods and variables) and thus are easy to identify, crosscutting concerns are not captured by a single program entity but are scattered over many program entities and are tangled with the other concerns. Because of their crosscutting nature, such crosscutting concerns are difficult to identify, and reduce the understandability of the system as a whole. In this paper, we report on a combined experiment in which we try to identify crosscutting concerns in the JHotDraw framework automatically. We first apply three independently developed aspect mining techniques to JHotDraw and evaluate and compare their results. Based on this analysis, we present three interesting combinations of these three techniques, and show how these combinations provide a more complete coverage of the detected concerns as compared to the original techniques individually. Our results are a first step towards improving the understandability of a system that contains crosscutting concerns, and can be used as a basis for refactoring the identified crosscutting concerns into aspects. M. Ceccato is a PhD student in ITC-irst in Trento, Italy. He received his degree in Software Engineering from the University of Padova, Italy, in 2003. The master thesis concerned the Re-engineering of an existing big-sized data warehouse application. The project was developed in the Information Technology department in Alcoa Servizi. His research interests are on source code analysis and manipulation, especially for the the migration of object-oriented code to aspect-oriented programming. He collaborates with King’s College London and Loyola College in Maryland on the automatic support for this migration process. He has been involved in the organization and in the program committee of a number of AOP-related events, such as Late Workshop, in Chicago (2005) and in Bonn, Germany (2006), held within the major Aspect Oriented Programming conference (AOSD) and 3rd European Workshop on Aspects in Software (EWAS’06) in Enschede, The Netherlands. Marius Marin is a Ph.D. researcher in the Software Evolution Reseach Laboratory at Delft University of Technology, the Netherlands. He was granted an engineering degree by the Technical University of Civil Engineering, Bucharest, in 2000, and Licentiate in Economic Computer Science from the Academy of Economic Studies, Bucharest, in 2002. Before starting his Ph.D. studies, he worked as a software engineer in industry. His main research interests are in the area of reverse engineering, software modularization and modeling, and aspect-oriented software development. He is the main author of the publicly available aspect mining tool FINT and he publishes at international conferences in the aforementioned topics. He has been involved in program- and organizing committees of several workshops related to aspect mining. Kim Mens obtained his Ph.D. in Computer Science at the Vrije Universiteit Brussel, on “architectural conformance checking,” for which he used a declarative meta-programming approach. After his Ph.D. he became a full-time professor (chargé de cours) at the Université catholique de Louvain-la-Neuve (UCL). In addition to his current interest in logic meta-programming and intensional views, Kim Mens is one of the originators of the reuse contracts technique for automatically detecting conflicts in evolving software. He has been formally involved in several research networks related to software evolution. He has a strong interest in object-oriented and aspect-oriented software development and has actively participated in the organization of several workshops and conferences on those topics. He combines all these different research interests under the common denominator of co-evolution (between source code and earlier life-cycle software artifacts). Other research topics that fit this common theme and in which he is interested are software architecture, software maintenance, reverse engineering, software transformation, software restructuring and renovation, aspect mining and evolution of aspect programs. L. Moonen is an assistant professor in the Software Evolution Research Lab at Delft University of Technology and a researcher at the Centre for Mathematics and Computer Science (CWI), the Netherlands. His research interests are the design and development of advanced program analysis tools and techniques that support development, maintenance and evolution of large software systems. Concrete topics include the reverse engineering and exploration of views on software systems and their use for understanding and assessing software quality attributes such as evolvability, reliability and security. Dr. Moonen received an MSc (cum laude, Computer Science, 1996) and PhD (Computer Science, 2002) from the University of Amsterdam. He is one of the founders of the Software Improvement Group, a company that specializes in tools and consultancy to help organizations solve their legacy problems. He publishes regularly at, and serves on organizing-, steering- and program committees of, international workshops and conferences on reverse engineering (WCRE), source code analysis (SCAM), software maintenance (ICSM), program understanding (ICPC), reengineering (CSMR), aspect mining (Dagstuhl 06302, TEAM) and software security (CoBaSSA). Paolo Tonella is a senior researcher at ITC-irst, Trento, Italy. He received his laurea degree cum laude in Electronic Engineering from the University of Padova, Italy, in 1992, and his Ph.D. degree in Software Engineering from the same University, in 1999, with the thesis “Code Analysis in Support to Software Maintenance.” Since 1994 he has been a full time researcher of the Software Engineering group at ITC-irst. He participated in several industrial and European Community projects on software analysis and testing. He is the author of “Reverse Engineering of Object Oriented Code,” Springer, 2005. His current research interests include reverse engineering, aspect oriented programming, empirical studies, Web applications and testing. Tom Tourwé obtained the degree of Licentiate in Computer Science in 1997 and Ph.D. in Science in 2002 at the Vrije Universiteit Brussel. He is currently associated to the Centrum voor Wiskunde en Informatica, based in Amsterdam, The Netherlands, where he works as a post- doctoral researcher in the Ideals project. His main research interests lie in the broad area of software engineering, and include aspect-oriented software evolution and re-engineering in particular. He published several peer-reviewed articles on these topics in international journals and conferences, and organised a number of workshops on those themes.     

Guest Editorial: Special Issue on Software Maintenance and Evolution

In systems developed without aspect-oriented programming, code implementing a crosscutting concern may be spread over many different parts of a system. Identifying such code automatically could be of great help during maintenance of the system. First of all, it allows a developer to more easily find the places in the code that must be changed when the concern changes and, thus, makes such changes less time consuming and less prone to errors. Second, it allows the code to be refactored to an aspect-oriented solution, thereby improving its modularity. In this paper, we evaluate the suitability of clone detection as a technique for the identification of crosscutting concerns. To that end, we manually identify five specific crosscutting concerns in an industrial C system and analyze to what extent clone detection is capable of finding them. We consider our results as a stepping stone toward an automated "aspect miner” based on clone detection.     

Analysing refactoring dependencies using graph transformation

Refactoring is a widely accepted technique to improve the structure of object-oriented software. Nevertheless, existing tool support remains restricted to automatically applying refactoring transformations. Deciding what to refactor and which refactoring to apply still remains a difficult manual process, due to the many dependencies and interrelationships between relevant refactorings. In this paper, we represent refactorings as graph transformations, and we propose the technique of critical pair analysis to detect the implicit dependencies between refactorings. The results of this analysis can help the developer to make an informed decision of which refactoring is most suitable in a given context and why. We report on several experiments we carried out in the AGG graph transformation tool to support our claims.     

On the use of clone detection for identifying crosscutting concern code

In systems developed without aspect-oriented programming, code implementing a crosscutting concern may be spread over many different parts of a system. Identifying such code automatically could be of great help during maintenance of the system. First of all, it allows a developer to more easily find the places in the code that must be changed when the concern changes and, thus, makes such changes less time consuming and less prone to errors. Second, it allows the code to be refactored to an aspect-oriented solution, thereby improving its modularity. In this paper, we evaluate the suitability of clone detection as a technique for the identification of crosscutting concerns. To that end, we manually identify five specific crosscutting concerns in an industrial C system and analyze to what extent clone detection is capable of finding them. We consider our results as a stepping stone toward an automated "aspect miner" based on clone detection.     

Applying and evaluating concern-sensitive design heuristics

Manifestation of crosscutting concerns in software systems is often an indicative of design modularity flaws and further design instabilities as those systems evolve. Without proper design evaluation mechanisms, the identification of harmful crosscutting concerns can become counter-productive and impractical. Nowadays, metrics and heuristics are the basic mechanisms to support their identification and classification either in object-oriented or aspect-oriented programs. However, conventional mechanisms have a number of limitations to support an effective identification and classification of crosscutting concerns in a software system. In this paper, we claim that those limitations are mostly caused by the fact that existing metrics and heuristics are not sensitive to primitive concern properties, such as either their degree of tangling and scattering or their specific structural shapes. This means that modularity assessment is rooted only at conventional attributes of modules, such as module cohesion, coupling and size. This paper proposes a representative suite of concern-sensitive heuristic rules. The proposed heuristics are supported by a prototype tool. The paper also reports an exploratory study to evaluate the accuracy of the proposed heuristics by applying them to seven systems. The results of this exploratory analysis give evidences that the heuristics offer support for: (i) addressing the shortcomings of conventional metrics-based assessments, (ii) reducing the manifestation of false positives and false negatives in modularity assessment, (iii) detecting sources of design instability, and (iv) finding the presence of design modularity flaws in both object-oriented and aspect-oriented programs. Although our results are limited to a number of decisions we made in this study, they indicate a promising research direction. Further analyses are required to confirm or refute our preliminary findings and, so, this study should be seen as a stepping stone on understanding how concerns can be useful assessment abstractions. We conclude this paper by discussing the limitations of this exploratory study focusing on some situations which hinder the accuracy of concern-sensitive heuristics.     

Mining early aspects based on syntactical and dependency analyses

Aspect-Oriented Requirements Engineering focuses on the identification and modularisation of crosscutting concerns at early stages. There are different approaches in the requirements engineering community to deal with crosscutting concerns, introducing the benefits of the application of aspect-oriented approaches at these early stages of development. However, most of these approaches rely on the use of Natural Language Processing techniques for aspect identification in textual documents and thus, they lack a unified process that generalises its application to other requirements artefacts such as use case diagrams or viewpoints. In this paper, we propose a process for mining early aspects, i.e. identifying crosscutting concerns at the requirements level. This process is based on a crosscutting pattern where two different domains are related. These two different domains may represent different artefacts of the requirements analysis such as text and use cases or concerns and use cases. The process uses syntactical and dependency based analyses to automatically identify crosscutting concerns at the requirements level. Validation of the process is illustrated by applying it to several systems and showing a comparison with other early aspects tools. A set of aspect-oriented metrics is also used to show this validation.     

基于.NET Framework实现可容错AOP框架

为了消除传统面向对象开发模式在处理公共系统功能所产生的代码混乱、一致性差和扩展困难问题,在.NET Framework环境下,采用面向方面(aspect-oriented programming,AOP)模式,创建了方面管理器完全分离软件中横切多模块的系统功能,并新增加了异常处理传递机制,加强了面向方面的容错性能;并结合面向方面编程(object-oriented programming,OOP),建立了易于设计、理解和维护的系统,提高了代码的质量、产量及其扩展性.     

面向方面体系结构建模研究

面向方面体系结构建模是面向方面软件开发(AOSD)的重要组成部分,也是近些年面向方面领域研究的热点问题。传统的软件体系结构设计方法没有单独地考虑横切关注点。因此,在软件体系结构设计阶段,建模人员需要新的机制来描述这些横切关注点。本文首先提出一个以横切为中心的面向方面体系结构概念框架;然后通过在体系结构设计阶段引入该框架中的核心概念,提出一种在体系结构设计阶段建模横切关注点的方法,从而支持其在早期进行横切关注点的分离。     

Side-effect localization for lazy, purely functional languages via aspects

Many side-effecting programming activities, such as profiling and tracing, can be formulated as crosscutting concerns and be framed as side-effecting aspects in the aspect-oriented programming paradigm. The benefit gained from this separation of concerns is particularly evident in purely functional programming, as adding such aspects using techniques such as monadification will generally lead to crosscutting changes. This paper presents an approach to provide side-effecting aspects for lazy purely functional languages in a user transparent fashion. We propose a simple yet direct state manipulation construct for developing side-effecting aspects and devise a systematic monadification scheme to translate the woven code to monadic style purely functional code. Furthermore, we present a static and dynamic semantics of the aspect programs and reason about the correctness of our monadification scheme with respect to them.     

一种改进的基于活动轨迹的Aspect挖掘方法

面向方面程序设计是近年来提出的一种程序设计技术,通过将横切关注点封装成Aspect,实现软件系统复杂性的降低,系统可维护性和可扩展性的提高。Aspect挖掘的目标是识别遗产系统中的横切关注点,为遗产系统的面向方面改造提供支持。文章提出了一种改进的基于活动轨迹的Aspect挖掘方法,基于横切关注点具有不同的调用上下文等约束寻找方法调用轨迹中相同的方法调用模式。通过实例说明该方法提高了候选Aspect的查全率。     

Guest Editors' Introduction: Aspect-Oriented Programming

You can measure a software system's value by its modularity. The more modular the system, the easier it is to produce and extend. Aspect-oriented programming technologies aim to improve system modularity by modularizing crosscutting concerns. Global properties and programming and design issues can lead to crosscutting concerns--for example, error handling or transaction code, interacting features, and reliability and security. The guest editors introduce aspect-oriented programming and describe this special issue's articles, which explain the use of aspect-oriented programming to simplify enterprise and system software, the need to expand an interface's meaning in the presence of aspects, and the application of aspects to design and requirements activities.