Structured Review of Code Clone Literature

This report presents the results of a structured review of code clone literature. The aim of the review is to assemble a conceptual model of clone-related concepts which helps us to reason about clones. This conceptual model unifies clone concepts from a wide range of literature, so that findings about clones can be compared with each other

srcSlice: very efficient and scalable forward static slicing

A highly efficient lightweight forward static slicing approach is presented and evaluated. The approach does not compute the program/system dependence graph but instead dependence and control information is com-puted as needed while computing the slice on a variable. The result is a list of line numbers, dependent vari-ables, aliases, and function calls that are part of the slice for all variables (both local and global) for the entire system. The method is implemented as a tool, called srcSlice, on top of srcML, an XML representation of source code. The approach is highly scalable and can generate the slices for all variables of the Linux kernel in approximately 20min on a typical desktop. Benchmark results are compared with the CodeSurfer slicing tool from GrammaTech Inc., and the approach compares well with regard to accuracy of slices. Copyright

Web information systems: A study of maintenance, change and flexibility

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.Information Systems (IS’s) have provided organisations with huge efficiency gains and benefits over the years; however an outstanding problem that is yet to be successfully tackled is that of the troublesome maintenance phase. Consuming vast resources and thwarting business progression in a competitive global market place, system maintenance has been recognised as one of the key areas where IS is failing organisations. Organisations are too often faced with the dilemma of either replacement or the continual upkeep of an unwieldy system. The ability for IS’s to be able to adapt to exogenous influences is even more acute today than at any time in the past. This is due to IS’s namely, Web Information Systems (WIS’s) increasingly and continually having to accommodate the needs of organisations to interconnect with a plethora of additional systems as well as supporting evolving business models. The richness of the interconnectivity, functionalities and services WIS’s now offer are shaping social, cultural and economic behaviour on a truly global scale, making the maintenance of such systems and evermore pertinent issue. The growth and proliferation of WIS’s shows no sign of abating which leads to the conclusion that what some have termed as the ‘maintenance iceberg’ should not be ignored. The quandary that commercial organisations face is typically driven by two key aspects; firstly, systems are built on the cultural premise of using fixed requirements, with not enough thought or attention being paid to systems abilities to deviate from these requirements. Secondly, systems do not generally cope well with adapting to unpredictable change arising from outside of the organisations environment. Over the recent past, different paradigms, approaches and methods have attempted to make software development more predictable, controllable and adaptable, however, the benefits of such measures in relation to the maintenance dilemma have been limited. The concept of flexible systems that are able to cope with such change in an efficient manner is currently an objective that few can claim to have realised successfully. The primary focus of the thesis was to examine WIS post-development change in order to empirically substantiate and understand the nature of the maintenance phase. This was done with the intention to determine exactly ‘where’ and ‘how’ flexibility could be targeted to address these changes. This study uses an emergent analytical approach to identify and catalogue the nature of change occurring within WIS maintenance. However, the research framework design underwent a significant revision as the initial results indicated that a greater emphasis and refocus was required to achieve the research objective. To study WIS’s in an appropriate and detailed context, a single case study was conducted in a web development software house. In total the case study approach was used to collect empirical evidence from four projects that investigated post-development change requests in order to identify areas of the system susceptible to change. The maintenance phases of three WIS projects were considered in-depth, resulting in the collection of over four hundred change requests. The fourth project served as a validation case. The results are presented and the findings are used to identify key trends and characteristics that depict WIS maintenance change. The analytical information derived from the change requests is consolidated and shown diagrammatically for the key areas of change using profile models developed in this thesis. Based on the results, the thesis concludes and contributes to the ongoing debate that there is a discernable difference when considering WIS maintenance change compared to that of traditional IS maintenance. The detailed characteristics displayed in the profile models are then used to map specific flexibility criteria that ultimately are required to facilitate change. This is achieved using the Flexibility Matrix of Change (FMoC) tool which was developed within the remit of this research. This tool is a qualitative measurement scheme that aligns WIS maintenance changes to a reciprocal flexibility attribute. Thus, the wider aim of this thesis is to also expand the awareness of flexibility and its importance as a key component of the WIS lifecycle

An interaction paradigm for impact analysis

The Aerospace industry is concerned with huge software projects. Software development is an evolving process resulting in larger and larger software systems. As systems grow in size, they become more complex and hence harder to maintain. Thus it appears that the maintenance of software systems is the most expensive part of the software life-cycle, often consuming 50-90% of a project total budget. Yet while there has been much research carried out on the problems of program and system development very little work has been done on the problem of maintaining developed programs. Thus it will be essential to improve the software maintenance process and the environment for maintenance. Historically, the term Software Maintenance has been applied to the process of modifying a software program after it has been delivered and during its life time. The high cost of software during its life cycle can be attributed largely to software maintenance activities, and a major part of these activities is to deal with the modifications of the software. These modifications may involve changes at any level of abstraction of a software system (i.e design, specification, code,...). Software Maintenance has to deal with modifications which can have severe Ripple Effects at other points in the software system. Impact Analysis addresses the problem and attempts to localize these Ripple Effects. In this thesis the Software Maintenance process and more specifically the Impact Analysis process is examined. The different parts of the implementation for the Impact Analysis System are explained. The main results of the thesis are the dependencies generation and the graph tool used to visualize these dependencies as well as the impacts on general dependency graph for impact analysis purpose

Automatic conversion of ADA source code to scala

Tese de mestrado, Engenharia Informática (Arquitetura, Sistemas e Redes de Computadores) Universidade de Lisboa, Faculdade de Ciências, 2020When the popularity of a programming language declines, there are often sizeable existing legacy codebases that need to be modernized. However, migrating off of these legacy languages is very costly. In addition, these declining languages do not necessarily have the same feature set as a modern language. As such, there are often specific features only present in the legacy language, which are useful for a variety of applications, making it hard for modern languages to penetrate these domains. This thesis presents a study of how these advanced features in legacy programming languages can be implemented in modern languages. As a use case, we will consider Ada, a language which is declining in popularity, and we evaluate which modern languages can adequately express Ada’s features. We select Scala as the most suitable language, due to its advanced type system, macro capabilities, implicit functions and constructors, and operator overloading. In addition, we present a set of translation rules from Ada to Scala, which was implemented in an automatic translation tool. Previous work on this domain tends to focus either on semantic correctness or on readability, eschewing one for the other, rather than tackling both at the same time. However, by carefully picking a target language with enough features that lend themselves for this kind of translation, we achieve a result that preserves both semantics and similarity, while maintaining an acceptable level of readability. We expect that this result to reduce the time and monetary cost of migrating off these legacy platforms, thereby making automated conversion of large software systems more viable

Web information systems : a study of maintenance, change and flexibility

Information Systems (IS’s) have provided organisations with huge efficiency gains and benefits over the years; however an outstanding problem that is yet to be successfully tackled is that of the troublesome maintenance phase. Consuming vast resources and thwarting business progression in a competitive global market place, system maintenance has been recognised as one of the key areas where IS is failing organisations. Organisations are too often faced with the dilemma of either replacement or the continual upkeep of an unwieldy system. The ability for IS’s to be able to adapt to exogenous influences is even more acute today than at any time in the past. This is due to IS’s namely, Web Information Systems (WIS’s) increasingly and continually having to accommodate the needs of organisations to interconnect with a plethora of additional systems as well as supporting evolving business models. The richness of the interconnectivity, functionalities and services WIS’s now offer are shaping social, cultural and economic behaviour on a truly global scale, making the maintenance of such systems and evermore pertinent issue. The growth and proliferation of WIS’s shows no sign of abating which leads to the conclusion that what some have termed as the ‘maintenance iceberg’ should not be ignored. The quandary that commercial organisations face is typically driven by two key aspects; firstly, systems are built on the cultural premise of using fixed requirements, with not enough thought or attention being paid to systems abilities to deviate from these requirements. Secondly, systems do not generally cope well with adapting to unpredictable change arising from outside of the organisations environment. Over the recent past, different paradigms, approaches and methods have attempted to make software development more predictable, controllable and adaptable, however, the benefits of such measures in relation to the maintenance dilemma have been limited. The concept of flexible systems that are able to cope with such change in an efficient manner is currently an objective that few can claim to have realised successfully. The primary focus of the thesis was to examine WIS post-development change in order to empirically substantiate and understand the nature of the maintenance phase. This was done with the intention to determine exactly ‘where’ and ‘how’ flexibility could be targeted to address these changes. This study uses an emergent analytical approach to identify and catalogue the nature of change occurring within WIS maintenance. However, the research framework design underwent a significant revision as the initial results indicated that a greater emphasis and refocus was required to achieve the research objective. To study WIS’s in an appropriate and detailed context, a single case study was conducted in a web development software house. In total the case study approach was used to collect empirical evidence from four projects that investigated post-development change requests in order to identify areas of the system susceptible to change. The maintenance phases of three WIS projects were considered in-depth, resulting in the collection of over four hundred change requests. The fourth project served as a validation case. The results are presented and the findings are used to identify key trends and characteristics that depict WIS maintenance change. The analytical information derived from the change requests is consolidated and shown diagrammatically for the key areas of change using profile models developed in this thesis. Based on the results, the thesis concludes and contributes to the ongoing debate that there is a discernable difference when considering WIS maintenance change compared to that of traditional IS maintenance. The detailed characteristics displayed in the profile models are then used to map specific flexibility criteria that ultimately are required to facilitate change. This is achieved using the Flexibility Matrix of Change (FMoC) tool which was developed within the remit of this research. This tool is a qualitative measurement scheme that aligns WIS maintenance changes to a reciprocal flexibility attribute. Thus, the wider aim of this thesis is to also expand the awareness of flexibility and its importance as a key component of the WIS lifecycle.EThOS - Electronic Theses Online ServiceGBUnited Kingdo