All software systems, no matter how they are designed, are subject to continuous evolution and maintenance activities to eliminate defects and extend their functionalities. This is particularly true for object-oriented systems, where we may develop different software systems using the same internal library or framework. These systems may evolve in quite different directions in order to cover different functionalities. Typically, there is the need to analyze their evolution in order to redefine the library or framework boundaries. This is a typical problem of software reengineering analysis. In this paper, we describe metrics, based on duplication analysis, that contribute to the process of reengineering analysis of object-oriented systems. These metrics are the basic elements of a reengineering analysis method and tool. Duplication analyses at the file, class and method levels have been performed. A structural analysis using metrics that capture similarities in class structure has been also exploited. In order to identify the best approach for the reengineering analysis of object-oriented systems, a comparison between the two approaches is described. In this paper, a case study based on real cases is presented, in which the results obtained by using a reengineering process with and without the analysis tool are described. The purpose of this study is to discover which method is the most powerful and how much time reduction can be obtained by its use.

In this paper an abstract of the Ph.D. thesis discussed at the University of Florence by the author is presented. The main focus of the thesis was in the identification and validation, both theoretical and empirical, of Object-Oriented metrics for complexity, and then, effort estimation. Complexity/effort metrics have been validated against test cases for verifying effectiveness of the estimation for evaluating development and maintenance effort.

Many software systems built in recent years have been developed using object-oriented technology and, in some cases, they already need adaptive maintenance in order to satisfy market and customer needs. In most cases, the estimation and prediction of maintenance effort is performed with difficulty due to the lack of metrics and suitable models. In this paper, a model and metrics for estimation/prediction of adaptive maintenance effort are presented and compared with some other solutions taken from the literature. The model proposed can be used as a general approach for adopting well-known metrics (typically used for the estimation of development effort) for the estimation/prediction of adaptive maintenance effort. The model and metrics proposed have been validated against real data by using multilinear regression analysis. The validation has shown that several well-known metrics can be profitably employed for the estimation/prediction of maintenance effort.

Object oriented modeling has been largely adopted in industry in the last few years. Several systems built 4 or 5 years ago may need an adaptive maintenance process in order to better satisfy market and customer needs. A model for effort estimation/prediction of the adaptive maintenance is presented. A selection of metrics for effort estimation has been applied to the general model for evaluating maintenance effort. The metrics presented have been validated against real data. The validation presented has shown that some metrics that can be profitably employed for effort estimation/prediction can be also used with success for the estimation/prediction of the maintenance effort. Moreover the results obtained give some guidelines for maintenance of control of relevant factors for adaptive maintenance.

A wide increment of object-oriented diffusion has been registered. This is accompanied by the needs of metrics and tools for assessing class reusability, maintainability, complexity, etc. Metrics have to produce confident results and have to be continuously revalidated on the basis of the specific purpose of their adoption. Tools for system assessment must be capable of satisfying the needs of each company by supporting the definition of more specific metrics and by providing appropriate views of software characteristics. These views are useful to give the developers as well as the managers immediately understandable representations of the system status. In this paper a new approach is proposed for system assessment. This approach is based on the adoption of new and well-known metrics together with a set of histograms and profiles that give a clear characterization of the system under development. The semantics of these histograms has been validated against several projects. A brief overview of the tool, TAC++, developed for system assessment is also included.

Owing to the growing diffusion of the object-oriented paradigm and the need to keep the process of software development under control, industries are looking for metrics/indicators capable of evaluating system evolution to control quality, reusability, maintainability, etc. Some new metrics are proposed for monitoring system development and maintenance. These metrics are used with a set of histograms to give a clear characterization of the system under development. Histograms call be profitably used to detect critical conditions during the system life-cycle. The semantics of these histograms has been validated against several projects: an example is also reported.