Aspect-Oriented Framework for Web Services (AoF4WS): Introduction and Two Example Case Studies

Aspect-Oriented Framework for Web Services (AoF4WS): Introduction and Two Example Case Studies

Ghita Kouadri Mostefaoui (Oxford University Computing Laboratory, UK), Zakaria Maamar (Zayed University, UAE) and Nanjangud C. Narendra (IBM India Research Lab, India)
Copyright: © 2009 |Pages: 19
DOI: 10.4018/978-1-60566-042-4.ch011
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Abstract

This chapter presents our research initiative known as aspect-oriented framework for Web services (AoF4WS). This initiative looks into the role of aspect-oriented programming in enhancing Web services with nonfunctional properties that are orthogonal to the primary functional properties of Web services, without the need for extensive reprogramming. This enhancement achieves a separation between the functional and nonfunctional aspects of Web services, thereby resulting in easier adaptability and maintainability. We have initially chosen to focus on security and self-healing nonfunctional requirements. The AoF4WS initiative is therefore demonstrated using two projects, SC-WS and SH-WS, which respectively stand for security concerns of Web services and self-healing Web services. Our contributions are relevant to the design phase in an aspect-oriented software development lifecycle.
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Introduction And Motivations

Web services are an attractive approach for implementing loosely-coupled business processes, which usually spread over companies’ boundaries (Ma, 2005). Over the last few years several efforts have been put into the development of standards related to Web services definition, announcement/discovery, and composition, just to cite a few. The dynamic nature of the business world highlights the continuous pressure on businesses to reduce expenses, increase revenues, generate profits, and remain competitive. This calls for a quick reaction to the market trends, a quick handling of users’ needs, a quick adaptation to unforeseen changes, and last but not least, a quick understanding of forthcoming challenges. To boost the acceptance level of Web services by the IT community as the technology of choice when developing flexible processes, Web services need to adapt to changing nonfunctional requirements with minimal reprogramming and minimal maintenance effort, so that they can be kept independent from the core Web services functionality. Security and self-healing are samples of nonfunctional requirements, and we will be highlighting them in this chapter.

Integrating security and self-healing capabilities into Web services calls for a clear separation between “business” and “management” concerns along which a Web service is defined (Figure 1). For this purpose, we adopt an aspect-oriented programming (AOP) approach to specify and implement this separation (Cottenier & Elrad, 2004; El-Manzalawy, 2005). This approach is part of our long-term research initiative known as aspect-oriented framework for Web services (AoF4WS). This initiative aims at examining the role of aspects in decoupling various concerns in Web services like security and self-healing. The separation between “business” and “management” sides emphasizes the noninvasive requirement that needs to be taken into consideration during the development cycle of a nonfunctional requirement. The mechanisms related, for instance, to security should be confined into one module and thus, should not scatter over the rest of modules of the Web service. Figure 1 illustrates the way concern separation occurs in a fictive Web service referred to as HotelBooking. The business side focuses on details directly related to hotel booking, like checking room availability, rate verification, and confirming client reservation. The management side of a Web service gathers all modules, such as security, self-healing, and monitoring that back the operations of this Web service. Constituents of the management side to be implemented as aspects need to be factored out of the core logic of the Web service.

Figure 1.

Concern separation in a Web service

In the following, we describe the two projects that we have chosen as part of the Ao4FWS initiative. The SC-WS project stands for security concerns of Web services and the SH-WS project stands for self-healing Web services. In Section 2 we present some basic definitions necessary for understanding the chapter. A motivating scenario is also presented in this section. SC-WS and SH-WS projects are described in Section 3 and Section 4, respectively. The chapter concludes in Section 5.

Complete Chapter List

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Table of Contents
Foreword
Torbjørn Skramstad
Preface
Khaled M. Khan
Acknowledgment
Khaled M. Khan
Chapter 1
Ghita Kouadri Mostefaoui
The ultimate effectiveness in terms of quality achievements should be a key concern of systems built from Web services. To this end, in this chapter... Sample PDF
The Development, Testing, and Deployment of a Web Services Infrastructure for Distributed Healthcare Delivery, Research, and Training
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Chapter 2
Abdelghani Benharref, Mohamed Adel Serhani, Mohamed Salem, Rachida Dssouli
Web services are a new breed of applications that endorse large support from main vendors from industry as well as academia. As the Web services... Sample PDF
Multi-Tier Framework for Management of Web Services' Quality
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Chapter 3
Krishna Ratakonda
In this chapter we present an overview of research and development efforts across several different technical communities aimed at enabling... Sample PDF
Quality Models for Multimedia Delivery in a Services Oriented Architecture
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Chapter 4
Julio Fernández Vilas
Several open issues in Web services architecture are being solved by using different kinds of solutions. Standard high-availability techniques based... Sample PDF
Virtual Web Services: Extension Architecture to Alleviate Open Problems in Web Services Technology
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Chapter 5
Witold Abramowicz
The following chapter focuses on the problem of the proper definition of non-functional properties and methods that may be applied in order to... Sample PDF
Profiling of Web Services to Measure and Verify their Non-Functional Properties
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Chapter 6
Kyriakos Kritikos
As the Web service (WS) paradigm gains popularity for its promise to transform the way business is conducted, the number of deployed WSs grows with... Sample PDF
Enhancing the Web Service Description and Discovery Processes with QoS
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Chapter 7
Michael C. Jaeger, Matthias Werner
This chapter presents the definition of relevant terminology and a conceptual model of the basic terms. The chapter starts with the presentation of... Sample PDF
Web Services Dependability
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Chapter 8
Frederic Montagut, Refik Molva, Silvan Tecumseh Golega
Composite applications leveraging the functionalities offered by Web services are today the underpinnings of enterprise computing. However, current... Sample PDF
Transactional Composite Applications
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Chapter 9
Enrico Pontelli, Tran Cao Son, Chitta Baral
This chapter presents a comprehensive logic programming framework designed to support intelligent composition of Web services. The underlying model... Sample PDF
A Logic Programming Based Framework for Intelligent Web Service Composition
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Chapter 10
Daniel Brenner, Barbara Paech, Matthias Merdes, Rainer Malaka
For the foreseeable future, testing will remain the mainstay of software quality assurance and measurement in all areas of software development... Sample PDF
Enhancing the Testability of Web Services
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Chapter 11
Ghita Kouadri Mostefaoui, Zakaria Maamar, Nanjangud C. Narendra
This chapter presents our research initiative known as aspect-oriented framework for Web services (AoF4WS). This initiative looks into the role of... Sample PDF
Aspect-Oriented Framework for Web Services (AoF4WS): Introduction and Two Example Case Studies
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Chapter 12
Ty Mey Eap, Marek Hatala, Dragan Gaševic, Nima Kaviani, Ratko Spasojevic
The lack of intrinsic and user control in the identity management of today Internet security hampers the research in the area of Semantic Web and... Sample PDF
Open Security Framework for Unleashing Semantic Web Services
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Chapter 13
Vishal Dwivedi
This chapter underlines the importance of security service level agreements (SLAs) for Web services. As Web services are increasingly incorporated... Sample PDF
Providing Web Services Security SLA Guarantees: Issues and Approaches
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Chapter 14
Fatih Oguz
This chapter describes a research study with an objective to explore and describe decision factors related to technology adoption. The study... Sample PDF
Adoption of Web Services in Digital Libraries: An Exploratory Study
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Chapter 15
Bijoy Majumdar
Change is the only constant, and this concept holds good for services too. Service maintenance is the most tedious and longest phase of service... Sample PDF
Service Evolution and Maintainability
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Chapter 16
Pauline Ratnasingam
This chapter aims to examine the extent of Web services usage and quality, applying the balanced scorecard methodology in a small business firm as... Sample PDF
The Role of Web Services: A Balance Scorecard Perspective
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About the Contributors