Maintaining object-oriented software

The maintenance requirements of object-oriented software, including the ability to make changes easily and an in-depth understanding of the software's structure and behavior, are discussed. The problems encountered by a maintainer trying to understand object-oriented software by reading and statically analyzing it are described. The problems caused by dynamic binding, polymorphism, and cooperating object classes in object-oriented software maintenance are reviewed     

架构和面向对象技术在PLC软件开发中的应用

为降低开发实时多任务控制系统PLC软件的复杂性、提高软件开发效率和质量,把架构和对象技术引入了PLC软件开发。结合对象技术和控制系统特点,强调了抽象对象的概念,提出了被控对象和控制器对象分离的思想,指出了对象技术的适用范围,设计了PLC控制软件架构的结构模型和控制风格。该模型中单元机器级应用对象技术,在单元机器控制软件内部应用面向任务分析与设计方法,并在一个分布式输送机组的控制软件中实现了该模型。     

Managing object-oriented software development

Managing object-oriented projects is subtly different than managing non-object-oriented ones. Object-oriented projects employ a different unit of decomposition, they encourage an incremental and iterative process, and quantitatively, they demand different kinds of measures. This paper examines the nature of managing object-oriented projects, and offers a variety of lessons learned from a number of real projects.Portions of this article are adapted from [Booch 1995].     

Economics of software reuse

The author discusses the type of software that can and should be reused. At least 10 different software artifacts lend themselves to reusability. Breaking down the cost of manually producing these 10 artifacts lets us create a preliminary analysis of the return on investment (ROI) of reusing them, with an admittedly large margin of error. He discusses the barriers to full software reusability     

面向对象软件的技术度量

软件度量学是软件工程领域的一个重要研究方向。通过软件度量,可以改进软件的体系结构,采用合适的软件开发过程,从而降低软件开发的成本,提高软件开发的效率,保证软件能满足用户的需求,开发出高质量的软件。分析了面向对象软件度量的特点,阐述了常用的面向对象软件度量方法,并在此基础上提出了以切片为中心的度量方法。     

面向对象软件的测试评估

软件测试的目的是发现错误,而不是确认其正确性,是为了增强人们对软件能够按照需求者的期望正确运行的信心,因此需要对软件测试质量进行度量.由于面向对象软件所具有的特性,面向对象软件的测试的度量相对于在过程测试中的测试度量已经不再适应.利用切片和领域的概念,通过多层次的测试度量来对面向对象软件的测试进行评估,该方法能够为改进对面向对象软件系统的测试过程和测试策略提供帮助.     

Managing software productivity and reuse

Your organization can choose from three main strategies for improving its software productivity. You can work faster, using tools that automate or speed up previously labor-intensive tasks. You can work smarter, primarily through process improvements that avoid or reduce non-value-adding tasks. Or you can avoid unnecessary work by reusing software artifacts instead of custom developing each project. Which strategy will produce the highest payoff? The author performed an extensive analysis that addressed this question for the US Department of Defense. The result of this analysis showed that work avoidance via software reuse produced the highest improvement in software productivity. The article gives advice on how to manage software reuse and the pitfalls to avoid     

Success and failure factors in software reuse

This paper aims at identifying some of the key factors in adopting or running a company-wide software reuse program. Key factors are derived from empirical evidence of reuse practices, as emerged from a survey of projects for the introduction of reuse in European companies: 24 such projects performed from 1994 to 1997 were analyzed using structured interviews. The projects were undertaken in both large and small companies, working in a variety of business domains, and using both object-oriented and procedural development approaches. Most of them produce software with high commonality between applications, and have at least reasonably mature processes. Despite that apparent potential for success, around one-third of the projects failed. Three main causes of failure were not introducing reuse-specific processes, not modifying nonreuse processes, and not considering human factors. The root cause was a lack of commitment by top management, or nonawareness of the importance of those factors, often coupled with the belief that using the object-oriented approach or setting up a repository seamlessly is all that is necessary to achieve success in reuse. Conversely, successes were achieved when, given a potential for reuse because of commonality among applications, management committed to introducing reuse processes, modifying nonreuse processes, and addressing human factors     

Repository evaluation of software reuse

The use and benefits of repository evaluation of software reuse are illustrated through an analysis of the evolving repositories of two large firms that recently implemented integrated CASE development tools. The analysis shows that these tools have supported high levels of software reuse, but it also suggests that there remains considerable unexploited reuse potential. The findings indicate that organizational changes will be required before the full potential of the new technology can be realized     

The impact of software evolution and reuse on software quality

This paper presents a case study of a software project in the maintenance phase. The case study was based on a sample of modules, representing about 1.3 million lines of code, from a very large telecommunications system. Software quality models were developed to predict the number of faults expected from the coding through operations phases. Since modules from the prior release were often reused to develop a new release, one model incorporated reuse data as additional independent variables. We compare this model's performance to a similar model without reuse data.Software quality models often have product metrics as the only input data for predicting quality. There is an implicit assumption that all the modules have had a similar development history, so that product attributes are the primary drivers of different quality levels. Reuse of software as components and software evolution do not fit this assumption very well, and consequently, traditional models for such environments may not have adequate accuracy. Focusing on the software maintenance phase, this study demonstrated that reuse data can significantly improve the predictive accuracy of software quality models.     

面向对象软件测试及度量的研究

软件测试方法和度量是提高和保证软件质量的关键,文中介绍了一种认识面向对象软件集成测试和试想量的方法（URI）,以及一种继承树深度（DIT）的度量标准,从这一测试方法显示继承的过多使用将增加软件测试的复杂性,论文最后介绍了有待进一步研究的问题。     

Aligning the economic modeling of software reuse with reuse practices

In contrast to current practices where software reuse is applied recursively and reusable assets are tailored trough parameterization or specialization, existing reuse economic models assume that (i) the cost of reusing a software asset depends on its size and (ii) reusable assets are developed from scratch. The contribution of this paper is that it provides modeling elements and an economic model that is better aligned with current practices. The functioning of the model is illustrated in an example. The example also shows how the model can support practitioners in deciding whether it is economically feasible to apply software reuse recursively.     

Value based software reuse investment

A number of issues are covered in this paper. Chief among them is the need for greater discipline in understanding the economic benefits of software reuse within the context of a broader business strategy. While traditional methods fail to account for growth opportunities and flexibility generated by investments in reuse, the introduction of option pricing theory can greatly enhance the design and evaluation of software reuse projects. Similarly, the disciplines of business strategy hold promise to help to fill the void of “strategic context” within which reuse investment happens.     

A model for software reuse

Software reusability is widely believed to be a key to help overcome the ongoing software crisis by improving software productivity and quality. New computer technology and the demands of an advancing society require new and more complicated software. It is unrealistic to expect that every software system can be developed solely reusing existing software; however, software reusability has proven to be a way of enhancing software productivity and quality in different organizations. It is also believed that reuse of code segments alone does not significantly reduce software development effort.By creating reuse support information while software is being developed (when the software is best known to software developers), the reuse effort for both software development and maintenance can be potentially reduced.In this paper, five types of RSI are presented: Semantic Web, Horizontal Web, Vertical Web, Syntactic Web, and Alternative Web. We collectively call these five webs a Quintet Web. The Semantic Web enables software developers to locate a software segment. The Horizontal Web provides a means to reuse a block of soflware along with other types of software from other phases of a development process. The inter-phase integration of software can be performed through this Web. The Vertical Web identifies the vertical relationship of a software block to its operational environment. The Syntactic Web locates all statements in which a variable is used. The Alternative Web provides alternative software blocks that perform an identical operation.A prototype of the Quintet Web is presented.     

Domain analysis for software reuse

A theory of domain knowledge is proposed that consists of ‘grounded domains' that model a set of cooperating objects that achieve a purpose. Grounded domains have spatial presence in the real world and contain agents that act on objects within a context of structures. More complex meta-domains use grounded domains as their subject matter and describe education, management, etc. The third component of the theory, generic tasks, describes problem solving activity such as diagnosis, searching, planning and scheduling. Generic tasks describe the behavioural components in both grounded and meta-domains. The reusable library of generic models is applied to the design of interactive systems by reusing the models as templates, and to reuse design knowledge in the form of associated design rationale. A process for recognising generic models is described with recognition heuristics structured in a walkthrough type of analysis for identifying key abstractions in new applications. The design process is illustrated with an information retrieval case study developed as a decision support system for emergency management, reusing information searching services. The discussion reviews the prospects for reusable patterns in interactive systems design, and similar approaches in software and knowledge engineering.     

面向对象的方法在软件设计中的应用研究

文中结合一个大型税收管理信息系统的开发,详细介绍了一种面向对象的系统设计方法的实施步骤、组织关系和分析评价,侧和理实用性。     

Organisational considerations for software reuse

Reuse is widely promoted as one of the most promising methods for increasing productivity and quality within software development. Until recently most research into strategies for systematic reuse has focused on solution of the technical issues. Now as companies (mostly IT focused) implement the strategies developed, they find there are other issues which hold back their success, somewhat unrelated to the technical solutions offered. Reuse processes are not simple technologies and methods slotted into a development, like the transition in design notation from traditional approaches to an object-;orientated method. Whereas technology changes involve retraining developers. Reuse requires the whole organisation and funding of development to be revised. If the magnitude of change involved in transitioning an IT organisation is so encompassing, where does this leave the rest of industry which is increasingly reliant on software to support their business process? This paper looks at organisational and management issues raised by the introduction of software reuse to the development process. We identify inhibitors of reuse adoption, look at causes of these and suggest possible solutions. We aim to concisely present all those non-;technical issues that should be considered when introducing a reuse program. Considered also is how these issues affect companies which have IT in only a business support capacity, making this paper relevant throughout industry.     

Negotiated interfaces for software reuse

A significant barrier to the reuse of software is the rigid interface presented by a subroutine. For nontrivial data structures, it is unlikely that the existing form of the data of an application will match the requirements of a separately written subroutine. The authors describe two methods of interfacing existing data to a subroutine: generation of a program to convert the data to the form needed by the subroutine, and rewriting the subroutine, through compilation, to fit the existing data. Both methods can be invoked through easily used menu-based negotiation with the user. These methods have been implemented using the GLISP language and compiler