An Empirical Study of a Repeatable Method for Reengineering Procedural Software Systems to Object- Oriented Systems

This paper describes a repeatable method for reengineering a procedural system to an object-oriented system. The method uses coupling metrics to assist a domain expert in identifying candidate objects. An application of the method to a simple program is given, and the effectiveness of the various coupling metrics are discussed. We perform a detailed comparison of our repeatable method with an ad hoc, manual reengineering effort based on the same procedural program. The repeatable method was found to be effective for identifying objects. It produced code that was much smaller, more efficient, and passed more regression tests than the ad hoc method. Analysis of object-oriented metrics indicated both simpler code and less variability among classes for the repeatable method

Extraction of objects from legacy systems: an example using cobol legacy systems

In the last few years the interest in legacy information system has increased because of the escalating resources spent on their maintenance. On the other hand, the importance of extracting knowledge from business rules is becoming a crucial issue for modern business: sometime, because of inappropriate documentation, this knowledge is essentially only stored in the code. A way to improve their use and maintainability in the present environment is to migrate them into a new hardware / software platform reusing as much of their experience as possible during this process. This migration process promotes the population of a repository of reusable software components for their reuse in the development of a new system in that application domain or in the later maintenance processes. The actual trend in the migration of a legacy information system, is to exploit the potentialities of object oriented technology as a natural extension of earlier structured programming techniques. This is done by decomposing the program into several agent-like modules communicating via message passing, and providing to this system some object oriented key features. The key step is the "object isolation", i.e. the isolation of .groups of routines and related data items : to candidates in order to implement an abstraction in the application domain. The main idea of the object isolation method presented here is to extract information from the data flow, to cluster all the procedures on the base of their data accesses. It will examine "how" a procedure accesses the data in order to distinguish several types of accesses and to permit a better understanding of the functionality of the candidate objects. These candidate modules support the population of a repository of reusable software components that might be used as a basis of the process of evolution leading to a new object oriented system reusing the extracted objects

Business rules based legacy system evolution towards service-oriented architecture.

Enterprises can be empowered to live up to the potential of becoming dynamic, agile and real-time. Service orientation is emerging from the amalgamation of a number of key business, technology and cultural developments. Three essential trends in particular are coming together to create a new revolutionary breed of enterprise, the service-oriented enterprise (SOE): (1) the continuous performance management of the enterprise; (2) the emergence of business process management; and (3) advances in the standards-based service-oriented infrastructures. This thesis focuses on this emerging three-layered architecture that builds on a service-oriented architecture framework, with a process layer that brings technology and business together, and a corporate performance layer that continually monitors and improves the performance indicators of global enterprises provides a novel framework for the business context in which to apply the important technical idea of service orientation and moves it from being an interesting tool for engineers to a vehicle for business managers to fundamentally improve their businesses

A process model of maintenance with reuse: an investigation and an implementation abstract

Sixty to eighty per cent of the software life-cycle cost is spent on the software maintenance phase because software maintenance is usually more difficult than original development and legacy systems are generally large and complex. Software reuse has recently been considered as a best solution to enhance the productivity of a software development team and to reduce maintenance costs. In addition, Software Configuration Management (SCM) is a central part of software maintenance as it is associated with changing existing software and is a discipline for controlling these changes. Thus, both software reuse and SCM have been proposed for making a significant improvement in productivity, quality and cost. However, so far these two technologies have been investigated separately. In order for software reuse and SCM to produce effects by synergy, both approaches require to be introduced into a maintenance environment together. Since software reuse and SCM, and software reuse and software maintenance have many similarities in their activities, these disciplines can be integrated within a software maintenance environment. This research has therefore developed an integrated process model for 'Maintenance with Reuse (MwR)', that supports SCM for a reuse library which is actively maintained for use in a software maintenance environment. This thesis addresses an integrated process model called the MwR model and its prototype tool TERRA (Tool for Evolution of a Reusable and Reconfigurable Assets Library) that consist of a configuration management (CM) process, reuse process, maintenance process and administration of a reuse library. The MwR model and TERRA provide reusers and maintainers with many activities of these four processes such as classifying, storing, retrieving, evaluating, and propagating reusable components, including controlling changes to both reusable components and existing systems. The process model of an integrated approach has been developed and validated using Process Weaver. The TERRA tool has been implemented on the WWW so that the prototype can provide portability, traceability, integration with existing tools, and a distributed maintenance environment. The TERRA prototype has been tested and evaluated through a scenario based case study. Several scenarios based on real data have been created and used for the case study so that an organisation can apply the model and tool to its maintenance environment without many problems. The software maintenance community is facing serious problems with legacy systems, such as a ever increasing frequency of changes and backlogs, lack of integrated tools and methods, and lack of software maintenance support environments. The control and management of changes to the software components in a reuse repository are crucial to successful software development and maintenance. If the component is being used in multiple systems effects of uncontrolled change are more critical. However, reuse libraries and servers currently available have not been successful as they do not support further development or maintenance of the reusable components. In addition, most of them are not sophisticated since they have not been linked to a development/maintenance environment. The integrated model of MwR can overcome many problems that exist in software maintenance and reuse through introduction of SCM functionalities into a maintenance environment. Thus, the integration of these common activities will greatly contribute to enhancing the productivity and quality of software, and will additionally lead to reducing the costs and backlogs of changes within a maintenance environment

A method for re-modularising legacy code

This thesis proposes a method for the re-modularisation of legacy COBOL. Legacy code often performs a number of functions that if split, would improve software maintainability. For instance, program comprehension would benefit from a reduction in the size of the code modules. The method aims to identify potential reuse candidates from the functions re-modularised, and to ensure clear interfaces are present between the new modules. Furthermore, functionality is often replicated across applications and so the re-modularisation process can also seek to reduce commonality and hence the overall amount of a company's code requiring maintenance. A 10 step method is devised which assembles a number of new and existing techniques into an approach suitable for use by staff not having significant reengineering experience. Three main approaches are used throughout the method; that is the analysis of the PERFORM structure, the analysis of the data, and the use of graphical representations. Both top-down and bottom-up strategies to program comprehension are incorporated within the method as are automatable, and user controlled processes to reuse candidate selection. Three industrial case studies are used to demonstrate and evaluate the method. The case studies range in size to gain an indication of the scalability of the method. The case studies are used to evaluate the method on a step by step basis; both strong points and deficiencies are identified, as well as potential solutions to the deficiencies. A review is also presented to assesses the three main approaches of the methods; the analysis of the PERFORM and data structures, and the use of graphical representations. The review uses the process of software evolution for its evaluation using successive versions of COBOL software. The method is retrospectively applied to the earliest version and the known changes identified from the following versions are used to evaluate the re-modularisations. Within the evaluation chapters a new link within the dominance tree is proposed as is an approach for dealing with multiple dominance trees. The results show that «ach approach provides an important contribution to the method as well as giving a useful insight (in the form of graphical representations) of the process of software evolution

Applying Model-Driven Engineering to Development Scenarios for Web Content Management System Extensions

Web content management systems (WCMSs) such as WordPress, Joomla or Drupal have established themselves as popular platforms for instantiating dynamic web applications. Using a WCMS instance allows developers to add additional functionality by implementing installable extension packages. However, extension developers are challenged by dealing with boilerplate code, dependencies between extensions and frequent architectural changes to the underlying WCMS platform. These challenges occur in frequent development scenarios that include initial development and maintenance of extensions as well as migration of existing extension code to new platforms. A promising approach to overcome these challenges is represented by model-driven engineering (MDE). Adopting MDE as development practice, allows developers to define software features within reusable models which abstract the technical knowledge of the targeted system. Using these models as input for platform-specific code generators enables a rapid transformation to standardized software of high quality. However, MDE has not found adoption during extension development in the WCMS domain, due to missing tool support. The results of empirical studies in different domains demonstrate the benefits of MDE. However, empirical evidence of these benefits in the WCMS domain is currently lacking. In this work, we present the concepts and design of an MDE infrastructure for the development and maintenance of WCMS extensions. This infrastructure provides a domain-specific modelling language (DSL) for WCMS extensions, as well as corresponding model editors. In addition, the MDE infrastructure facilitates a set of transformation tools to apply forward and reverse engineering steps. This includes a code generator that uses model instances of the introduced DSL, an extension extractor for code extraction of already deployed WCMS extensions, and a model extraction tool for the creation of model instances based on an existing extension package. To ensure adequacy of the provided MDE infrastructure, we follow a structured research methodology. First, we investigate the representativeness of common development scenarios by conducting interviews with industrial practitioners from the WCMS domain. Second, we propose a general solution concept for these scenarios including involved roles, process steps, and MDE infrastructure facilities. Third, we specify functional and non-functional requirements for an adequate MDE infrastructure, including the expectations of domain experts. To show the applicability of these concepts, we introduce JooMDD as infrastructure instantiation for the Joomla WCMS which provides the most sophisticated extension mechanism in the domain. To gather empirical evidence of the positive impact of MDE during WCMS extension development, we present a mixed-methods empirical investigation with extension developers from the Joomla community. First, we share the method, results and conclusions of a controlled experiment conducted with extension developers from academia and industry. The experiment compares conventional extension development with MDE using the JooMDD infrastructure, focusing on the development of dependent and independent extensions. The results show a clear gain in productivity and quality by using the JooMDD infrastructure. Second, we share the design and observations of a semi-controlled tutorial with four experienced developers who had to apply the JooMDD infrastructure during three scenarios of developing new (both independent and dependent) extensions and of migrating existing ones to a new major platform version. The aim of this study was to obtain direct qualitative feedback about acceptance, usefulness, and open challenges of our MDE approach. Finally, we share lessons learned and discuss the threats to validity of the conducted studies

Identifying reusable functions in code using specification driven techniques

The work described in this thesis addresses the field of software reuse. Software reuse is widely considered as a way to increase the productivity and improve the quality and reliability of new software systems. Identifying, extracting and reengineering software. components which implement abstractions within existing systems is a promising cost-effective way to create reusable assets. Such a process is referred to as reuse reengineering. A reference paradigm has been defined within the RE(^2) project which decomposes a reuse reengineering process in five sequential phases. In particular, the first phase of the reference paradigm, called Candidature phase, is concerned with the analysis of source code for the identification of software components implementing abstractions and which are therefore candidate to be reused. Different candidature criteria exist for the identification of reuse-candidate software components. They can be classified in structural methods (based on structural properties of the software) and specification driven methods (that search for software components implementing a given specification).In this thesis a new specification driven candidature criterion for the identification and the extraction of code fragments implementing functional abstractions is presented. The method is driven by a formal specification of the function to be isolated (given in terms of a precondition and a post condition) and is based on the theoretical frameworks of program slicing and symbolic execution. Symbolic execution and theorem proving techniques are used to map the specification of the functional abstractions onto a slicing criterion. Once the slicing criterion has been identified the slice is isolated using algorithms based on dependence graphs. The method has been specialised for programs written in the C language. Both symbolic execution and program slicing are performed by exploiting the Combined C Graph (CCG), a fine-grained dependence based program representation that can be used for several software maintenance tasks