Pautasso / Bussler Emerging Web Services Technology

2007
ISBN: 978-3-7643-8448-7
Verlag: Springer
Format: PDF
Kopierschutz: Wasserzeichen (»Systemvoraussetzungen)

E-Book, Englisch, 184 Seiten, eBook

Reihe: Whitestein Series in Software Agent Technologies and Autonomic Computing

The Workshop on Emerging Web Services Technology (WEWST06) took place in conjunction with the 4th European Conference on Web Services (ECOWS’06) on 4th December 2006, in Zurich, Switzerland. Acting as the natural extension to the main ECOWS conference, the main goal of the WEWST workshop is serving as a forum for providing early exposure andmuchneededfeedbacktogrowandestablishoriginalandemergingideaswithin the Web Services community. The wide variety of tools, novel techniques and emergingtechnologicalsolutionspresentedinWEWSTshareone commonfeature: they advance the current Web services research in new directions by introducing new and sometimes controversial ideas into the ?eld. WEWST focuses on research contributions advancing the state of the art in Web services technologies in the following areas: Model Driven Engineering for SOA, Mobility and Services, Streaming Services and Event Driven Architectures, Dynamic Web Service Discovery and Composition, Lightweight Orchestration- gines, SLA Creation and Service Delivery, Semantic Web, Managing Change and Service Evolution, Business Driven Development, Service-Oriented Grid Comp- ing Middleware, Business Process Management for Web Services, Software and Service Engineering. WEWST covers the whole spectrum which makes it a very important part of ECOWS.

Zielgruppe

Research

Autoren/Hrsg.

Pautasso, Cesare

Bussler, Christoph

Inhaltsverzeichnis

Opening Keynote.- Ontoprise: Semantic Web Technologies at Business.- Service Management.- BPEL-Mora: Lightweight Embeddable Extensible BPEL Engine.- A Cross-Layer Approach to Performance Monitoring of Web Services.- Employing Intelligent Agents to Automate SLA Creation.- A Flexible Approach to Service Management-Related Service Description in SOAs.- Model Driven Engineering for Web Service Composition and Discovery.- Model Centric Approach of Web Services Composition.- Model Driven Design of Web Service Operations using Web Engineering Practices.- A Logic-based Approach for Service Discovery with Composition Support.- Mobile Services.- Mobile and Dynamic Web Services.- Software Metrics for the Efficient Execution of Mobile Services.- Web Service Technology Challenges.- Dynamically Adapting Clients to Web Services Changing.- Web Service Standards: Do we need them?.

Leseproben

Model Centric Approach of Web Services Composition (p. 65-66)

Ricardo Quintero, Victoria Torres and Vicente Pelechano Abstract. The development of composite Web Services is being specified in a more declarative way than imperative programming. In this context, conceptual modeling has been the most accepted solution. Conceptual modeling of Web services has been done using behavioral models (like activity diagrams) considering mainly the dynamic view. We believe that, besides the dynamic aspects, the models should capture structural requirements between web service operations. In this way, behavioral models could be complemented with a structural model. In this paper we introduce a Web service composition modeling solution, following the MDA approach, considering both -structural and dynamic properties- enriched with semantic constraints in order to automatically generate composite Web services implemented in BPEL. Keywords. Web Services, Composition, Conceptual Modeling, Web Engineering, MDA.

1. Introduction

Current e-business processes have, as an important requirement, the integration (the composition) of diverse application functionalities. The main strategy that has been followed by the industry is the use of Web Services to export the functionality and the use of programming languages to define service composition [11].

Because the majority of them were not designed with this goal in mind, they do not have abstractions for this objective, so usually the composition definitions are cumbersome. In contrast, conceptual modeling offers abstractions and models in order to define this composition at a high level of abstraction [12,13,14]. The main focus of these approaches is on dynamic concerns (as in UML Activity diagrams) forgetting the structural concerns. Although there are some model-driven solutions that generate in a semi-automatic way Web services and WS-BPEL [15], the problem with these modeling approaches is some lack of semantics that makes it difficult to capture the composition requirements in a precise way. This drawback does make it unfeasible to build modeling tools that validate models and generate complete and fully operative implementations. We consider that structural and dynamic models are needed in order to capture these issues, especially static and dynamic binding properties between the Web services that are being composed (the main focus of this work). Moreover it could be used as a way to export the functionality of the application: by means of methodological guidelines it is possible to detect functional groups from the business layer (specified by a structural model) and export them as a set of Web services. These Web services could be consumed by other applications to enable collaboration with other third parties. In this work we introduce, as a main contribution, two models (the Service Model and the Dynamic Model for Service Composition) which allow us specifying the structural and dynamic requirements of Web services compositions by using aggregation/ association relationships with a precise semantics, defined in the context of a multidimensional framework [3]. In order to obtain the equivalent software artifacts of these models we follow a Model driven approach where the application of a set of transformation rules generates the corresponding WS-BPEL specification.

This solution extends ourWeb engineering method Object-OrientedWeb Solutions (OOWS) [1] in order to capture the collaborative requirements that are necessary to produce (in an automatic way) complete collaborative Web applications. The remainder of the paper is structured as follows: section 2 explains our proposal to conceptual modeling of Services, section 3 shows the introduced models from the point of view of their structural properties, section 4 explains the dynamic properties and the transformation of the models to a specific Web service composition technology (in this case we choose WS-BPEL [4], although it can be another -like BPML [5]), section 5 explains our code generation strategy and finally, section 6 presents conclusions and further work.