Mapping Procedural Patterns to Object-Oriented Design Patterns

This paper presents a new approach to the use of design patterns for the reengineering of legacy code, using a mapping from procedural design patterns to object-oriented patterns. We show also how object-oriented design patterns can be formalised and correctness conditions for their application derived, in order to justify the preservation of functionality in the reengineering process. We give examples taken from case studies of reengineering legacy COBOL applications.     

软件重构中Visitor*设计模式和应用

对当前软件重构领域中的研究作了概括性介绍。对作为重构的主导思想和系统体系结构的总体转换方向的设计模式进行介绍,针对原有的Visitor设计模式在运行中操作调用频繁时资源消耗过大和运行效率降低的不足,在原模式基础上进行改良和优化,生成一种新的设计模式Visitor＊,并对其具体分析,通过操作函数的上移和accept方法的重定义,实现了操作定义由Element层到Visitor层的等价转化,大大节省资源和提高运行效率。最后运用Visitor^＊实现了一个面向对象设计过程中的重构,并结合一些重要概念对其进行具体分析。     

软件重构及设计模式在摄像头阅卷系统中的应用研究

首先设计并实现一个基于摄像头的阅卷系统,该系统由试卷获取、灰度化、二值化、畸变变换、倾斜校正、图像定位和识别等图像处理流程组成。然后以此为依据,通过对重构技术及设计模式原则和方法的系统研究,对该系统框架进行优化和重构。本文充分参照现有的设计模式,通过重构技术,改善现有代码的质量,增加系统的可维护性和可复用性。     

A Theory of Object-Oriented Design

Progress was made in the understanding of object-oriented (O-O) design through the introduction of patterns of design and architecture. Few works, however, offer methods of precise specification for O-O design.This article provides a well-defined ontology and an underlying framework for the formal specification of O-O design: (1) We observe key design motifs in O-O design and architectures. (2) We provide a computational model in mathematical logic suitable for the discussion in O-O design. (3) We use our conceptual toolkit to analyze and compare proposed formalisms.     

基于Java自动化重构工具的研究

重构可以改进软件设计、提高软件质量。自动化重构工具的使用可以避免手工重构时引入的错误,提高软件开发效率。通过对自动化重构技术的研究,结合Java语言的特点,给出了基于Java的重构分类,在此基础上开发了一个基于Java的自动化重构工具ARTJ,给出了ARTJ的模型,分析了它的工作原理和各主要组件的功能,并展示利用ARTJ自动实现程序的改进。     

基于Design Patterns的大型工控软件研究与实践

针对大型工控软件开发面临的各种难题，提出了基于设计模式(Design Patterns)的工控软件设计的解决方案．在大型电力系统监控软件设计中，采用设计模式进行工控软件框架和工位的设计，实现了功能模块的松耦合关系，降低了代码的复杂度，从而提高了运行效率，同时也加快了系统开发、调试的效率．论证了设计模式在工控软件设计中应用的潜力，提出了大型工控软件设计的新思路。     

应用遗传算法求解函数优化问题的程序实现

分析了应用遗传算法求解函数优化问题的程序设计中的常见问题，并分别提出了适用方法。     

一种从Z规约到并行程序的精化方法

提出了一种通过对设计模式进行精化,从Z规约开发并行程序的方法.该方法对Z语言进行了并行扩充,从Z功能规约出发,通过使用扩展的设计模式逐步精化得到并行的设计规约,再通过保持语义的转换,得到可最后转换为并行代码的抽象并行程序.通过实例对这一方法进行了详细的描述.     

Dynamic Query-Based Debugging of Object-Oriented Programs

Program errors are hard to find because of the cause-effect gap between the instant when an error occurs and when the error becomes apparent to the programmer. Although debugging techniques such as conditional and data breakpoints help in finding errors in simple cases, they fail to effectively bridge the cause-effect gap in many situations. This paper proposes two debuggers that provide programmers with an instant error alert by continuously checking inter-object relationships while the debugged program is running. We call such tool a dynamic query-based debugger. To speed up dynamic query evaluation, our debugger implemented in portable Java uses a combination of program instrumentation, load-time code generation, query optimization, and incremental reevaluation. Experiments and a query cost model show that selection queries are efficient in most cases, while more costly join queries are practical when query evaluations are infrequent or query domains are small. To enable query-based debugging in the middle of program execution in a portable way, our debugger performs efficient Java class file instrumentation. We call such debugger an on-the-fly debugger. Though the on-the-fly debugger has a higher overhead than a dynamic query-based debugger, it offers additional interactive power and flexibility while maintaining complete portability.     

公路设计中平、纵、横联合视图的编程及应用

针对常用公路 CAD 软件中路线平、纵、横成果只能独立显示,无法联合查询的问题,提出了实现平、纵、横成果联合显示、查询的编程思路,并介绍了该程序在设计中的应用,以期为提高设计工作效率提供更好的解决方案。     

Goto and Concurrency Introducing Safe Jumps in Esterel

Esterel is a design language for the specification of real time embedded systems. Based on the synchronous concurrency paradigm, its semantics describes execution as a succession of instants of computation. In this work, we consider the introduction of a new gotopause instruction in the language, which acts as a non-instantaneous jump instruction compatible with concurrency. It allows the programmer to activate state control points anywhere in the program, from where the execution is resumed in the next instant. In order to provide the formal semantics of the extended language, we first define a state semantics of Esterel, which we prove observationally equivalent to the original logical behavioral semantics. Including gotopause in the state semantics is then straightforward. We sketch two key applications of our new primitive: a direct encoding of automata and a quasi-linear rewriting of programs eliminating schizophrenic behaviors.     

Replicated Case Studies for Investigating Quality Factors in Object-Oriented Designs

Thispaper aims at empirically exploring the relationships betweenmost of the existing design coupling, cohesion, and inheritancemeasures for object-oriented (OO) systems, and the fault-pronenessof OO system classes. The underlying goal of this study is tobetter understand the relationship between existing design measurementin OO systems and the quality of the software developed. in addition,we aim at assessing whether such relationships, once modeled,can be used to effectively drive and focus inspections or testing.The study described here is a replication of an analogous studyconducted in a university environment with systems developedby students. In order to draw more general conclusions and to(dis)confirm the results obtained there, we now replicated thestudy using data collected on an industrial system developedby professionals. Results show that many of our findings areconsistent across systems, despite the very disparate natureof the systems under study. Some of the strong dimensions capturedby the measures in each data set are visible in both the universityand industrial case study. For example, the frequency of methodinvocations appears to be the main driving factor of fault-pronenessin all systems. However, there are also differences across studies,which illustrate the fact that, although many principles andtechniques can be reused, quality does not follow universal lawsand quality models must be developed locally, wherever needed.     

代码变更中抽取类重构模式的识别

在现代软件开发和维护中,重构是提高软件可维护性和软件质量的常用手段.而大量重构模式掺杂在日常的bug修复、功能增加等代码变更中,使得变更理解变得非常复杂.识别重构模式可以将重构与其它类型的代码变更隔离,利于变更理解.目前在识别重构模式的相关研究中,并没有结合变更类型和相似性比较的识别重构模式的方法及工具.为此,提出了一种基于细粒度变更类型和文本相似性比较识别重构模式的方法.将该方法应用于抽取类重构模式,并在4个开源项目中进行了实验,其平均准确率在82.6%左右.     

Higher-Order UnCurrying

We present a formal specification of unCurrying for a higher-order, functional language with ML-style let-polymorphism. This specification supports the general unCurrying of functions, even for functions that are passed as arguments or returned as values. The specification also supports partial unCurrying of any consecutive parameters of a function, rather than only unCurrying all of a function's parameters. We present the specification as a deductive system that axiomatizes a judgment relating a source term with an unCurried form of the term. We prove that this system relates only typable terms and that it is correct with respect to an operational semantics. We define a practical algorithm, based on algorithm , that implements unCurrying and prove this algorithm sound and complete with respect to the deductive system. This algorithm generates maximally unCurried forms of source terms. These results provide a declarative framework for reasoning about unCurrying and support a richer form of unCurrying than is currently found in compilers for functional languages.     

面向对象设计模式的C语言实现

介绍了C语言成为嵌入式技术领域主要的程序设计语言的原因,及当前用C语言所编写的程序仍然存在的问题,然后介绍了面向对象的设计模式的概念及优点.并提出将面向对象的思想与C语言结合起来,接着用C语言实现了部分面向对象的设计模式,给出了其代码,并做了相应的注释,为优化C程序的结构提供了途径.最后总结了在C程序中使用这些设计模式的价值.文中所指的C语言均为标准C（ANSIC）.     

Object-Oriented Databases with Relational DBMSs

The expediency of the use of object-oriented models of data as datalogical models in designing databases is shown, and methods of integration of relational and object-oriented models are considered. A relational scheme for storage of attributes and relations of object-oriented models is proposed.     

Adaptive Detection of Design Flaws

Criteria for software quality measurement depend on the application area. In large software systems criteria like maintainability, comprehensibility and extensibility play an important role.My aim is to identify design flaws in software systems automatically and thus to avoid “bad” — incomprehensible, hardly expandable and changeable — program structures.Depending on the perception and experience of the searching engineer, design flaws are interpreted in a different way. I propose to combine known methods for finding design flaws on the basis of metrics with machine learning mechanisms, such that design flaw detection is adaptable to different views.This paper presents the underlying method, describes an analysis tool for Java programs and shows results of an initial case study.