Service-Oriented Agents and Meta-Model Driven Implementation

Current efforts have not enforced Web services as loosely coupled and autonomous entities. Web services and software agents have gained different focuses and accomplishments due to their development and application backgrounds. This chapter proposes service-oriented agents (SOAs) to unify Web services and software agents. Web services features can be well realized through introducing software agents’ sophisticated software modeling and interaction behaviors. We present a natural framework to integrate their related technologies into a cohesive body. Several critical challenges with SOAs have been addressed. The concepts, system and component structures, a meta-model driven semantic description, agent-oriented knowledge representation, and an implementation framework are proposed and investigated. They contribute to the identified setbacks with Web services technologies, such as dynamic composition, semantic description, and implementation framework. A prototype of the proposed SOAs implementation framework has been implemented. Several economic services are working on it.

Service Patterns for Enterprise Information Systems

This chapter introduces service patterns for SOA-based enterprise systems. The authors believe that the deployment of such patterns would be of considerable value both as a best-practice guide for practitioners as well as a starting point for further research in their role in software engineering. A comprehensive catalog of service patterns is included in this chapter. In the catalog, each pattern is discussed in the context of selected examples and in terms of a brief description of its role, functionality, and deployment. For each pattern there are recommendations on implementation and a practical usage scenario.

Service-Oriented Enterprise Architecture

Service orientation is a new paradigm, not only for software engineering but also for the broader topic of enterprise architecture. This chapter studies the relevance and impact of the service concept and service orientation to the discipline of enterprise architecture. It provides ideas on how to set up a service-oriented enterprise architecture. It is argued that a service-oriented approach to enterprise architecture provides better handles for architectural alignment and business and IT alignment, in particular.

Service-Composition

This chapter provides an overview of the area of service composition. It does so by introducing a generic architecture for service composition and using this architecture to discuss some salient concepts and techniques. The architecture is also used as a framework for providing a critical view into a number of languages, standardization efforts, and tools related to service composition emanating both from academia and industry and to classify them in terms of the concepts and techniques that they incorporate or support (for example, orchestration and dynamic service selection). Finally, the chapter discusses some trends in service-oriented software systems engineering pertaining to service composition.

Building an Online Security System with Web Services

This chapter presents a case study where Web services are used to build a user-centric online security system. It explores complex technical challenges encountered with the use of the Web services and online security technologies. Furthermore, the authors hope that their practical experiences and findings will shed some lights on how the online security system should and can be built in the approach of being user-centric instead of vendor-centric and on the implications of embracing Web services to conventional software engineering processes.

Engineering a Service-Oriented Architecture in E-Government

Service-oriented enterprise architectures have gained considerable attention of politicians and public servants as a solution for designing new applications and leveraging investments in legacy systems. Service-oriented architectures can help to share data and functionality among information systems and provide the flexibility to include existing legacy systems, which cannot be replaced easily and otherwise restrict further development. In this chapter, the design of a service-oriented architecture in public administration is explored. A case study is conducted at the Ministry of Justice, and a service-oriented architecture is designed, implemented, and evaluated. The architecture is evaluated based on a number of quality requirements. This case study shows the feasibility to replace functionality formerly offered by legacy systems and shows limitations of current technology. This chapter should lead to a greater understanding of the concept of service-oriented architectures in e-government.

Security in Service-Oriented Architecture

This chapter covers the different facets of security as applicable to Service-Oriented Architecture (SOA) implementations. First, it examines the security requirements in SOA implementations, highlighting the differences as compared to the requirements of generic online systems. Later, it discusses the different solution mechanisms to address these requirements in SOA implementations. In the context of Web services, the predominant SOA implementation standards have a crucial role to play. This chapter critically examines the crucial Web services security standards in different stages of adoption and standardization. Later, this chapter examines the present-day common nonstandard security mechanisms of SOA implementations. Towards the end, it discusses the future trends in security for SOA implementations with special bearing on the role of standards. The authors believe that the pragmatic analysis of the multiple facets of security in SOA implementations provided here will serve as a guide for SOA security practitioners.

Service-Oriented Design Process Using UML

This chapter presents a worked example of a design process for Service-Oriented Architecture. It utilizes the industry standard modeling notation, the Unified Modeling Language (UML) from the Object Management Group, to present a practical design for services. The authors have used their real world experience on many service-oriented projects to develop a design method using visual modeling to implement high quality services and service implementation. The chapter introduces a terminology for services and their implementing components and then works through the example to show how the implementation is designed in UML. We hope that this will show the reader how services are implemented by organizations on real projects.

Web Services for Groupware

While some years ago the focus of many Groupware systems has been on the support of Web based information systems to support access with Web browsers, the focus today is shifting towards a programmatic access to software services, regardless of their location and the application used to manipulate those services. Whereas the goal of Web Computing has been to support group work on the Web (browser), Web services support for Groupware has the goal to provide interoperability between many Groupware systems. The contribution of this chapter is threefold: (1) to present a framework consisting of three levels of Web services for Groupware support, (2) to present a novel Web services management and configuration architecture with the aim of integrating various Groupware systems in one overall configurable architecture, and (3) to provide a use case scenario and preliminary proof -of-concept implementation. Our overall goal for this chapter is to provide a sound and flexible architecture for gluing together various Groupware systems using Web services technologies.

Architecture, Specification, and Design of Service-Oriented Systems

Service-oriented software systems (SOSS) are becoming the leading paradigm of software engineering. The crucial elements of the requirements specification of SOSSs are discussed as well as the relation between the requirements specification and the architecture of SOSS. It is preferable to understand service orientation not to be limited to Web services and Internet only. It is shown that there are several variants of SOSS having different application domains, different user properties, different development processes, and different software engineering properties. The conditions implying advantageous user properties of SOSS are presented. The conditions are user-oriented interfaces of services, the application of peer-to-peer philosophy, and the combination of different technologies of communication between services (seemingly the obsolete ones inclusive), and autonomy of the services. These conditions imply excellent software engineering properties of SOSSs as well. Service orientation promises to open the way to the software as a proper engineering product.