Reengineering of Legacy Systems to Distributed Environments.

The object-oriented paradigm and client/server and distributed technologies have become widely used in the last decade. There is an increasing interest to migrate and reengineer legacy systems to these new hardware technologies and software development paradigms. Software engineers who wish to reengineer such legacy systems face challenges, such as lack of documentation and programs that are difficult to comprehend. Middleware technologies such as CORBA and DCOM make the development of new distributed systems, as well as the migration of legacy systems to distributed platforms, more feasible. Distribution of a system consists of two parts: (1) subsystem decomposition and (2) allocation of the subsystems to different sites. In this research, we define a reengineering environment that assists with the migration of legacy systems to distributed environments. We define a reengineering methodology that uses reverse engineering, software metrics, clustering, and data mining to migrate legacy systems to object-based distributed environments. The reengineering environment includes the methodology and an integrated set of tools that support the implementation of the methodology. The methodology consists of multiple phases. First, we use reverse engineering techniques for program comprehension and design recovery. We then decompose the system into a hierarchy of subsystems by defining relationships between the entities of the underlying paradigm of the legacy system. The decomposition is driven by data mining, software metrics, and clustering techniques. Next, if the underlying paradigm of the legacy system is not object-based, we perform object-based adaptations on the subsystems. We then create components by wrapping objects and defining an interface. Finally, we allocate components to different sites by specifying the requirements of the system and characteristics of the network as an integer-programming model that minimizes the remote communication. We use middleware technologies for the implementation of the distributed object system

Metrics, Do They Really Help?

Maturing a well designed framework requires a set of software metrics to steer the iterative development process. Based on a case study of the VisualWorks/Smalltalk framework for user-interface building, we conclude that today's size and inheritance metrics are not reliable to detect problems but are useful in measuring stability. We expect that this work will contribute to the application of metrics as a project management tool

Metrics, Do They Really Help?

This paper presents a case study about a set of metrics for managing an iterative framework development process. The empirical data have been gathered from the VisualWorks#Smalltalk user-interface framework, which is one of the few industrial scale frameworks that provides full access to the di#erent releases of its source code. After providing some details about the case study and the metrics evaluated #section 2#, the paper continues with an evaluation of metrics for problem detection #section 3# and stability measurement #section 4#. Before coming to a conclusion #section 6#, the paper reports on related work on object-oriented metrics #section 5#