Web Services are the latest attempt to address the problems of integration of disparate systems and applications. The main idea behind the Web Service technology is standardization of communication formats and protocol in the simplest (and cheapest) way.

The main objective of this tutorial is to give a broad overview of the Web Service (WS) technology. Additionally, we aim at providing insight into the development of simple WSs and business processes based on Web Services (WSs). The ability to develop complex compositions of WSs is a problem that urgently needs solution and standardization in order to reveal the full strength of the Web Service technology.

This tutorial is organised in two parts. The first part's main focus is on the basic WS concepts and existing protocols. The second part shows how simple WSs can be crated and composed in more complex ones using a process-based approach.

The first part of the tutorial deals with the fundamental concepts of the WSs paradigm. We also show how WSs relate to the service-oriented computing. We make a broad overview of the standard WSs protocol stack (including XML, SOAP, WSDL, UDDI), and the currently available proposal specifications for building WSs-based business processes (especially BPEL4WS) and the corresponding implementations. The main goal is to discuss and reveal the advantages and disadvantages of WSs in different application scenarios, especially in the case of bridging different platforms and applications in a heterogeneous environment.

The second part of the tutorial tackles the practical issues of the process of development and deployment of simple and composite WSs. The process of creating Web services is illustrated in detail using comprehensive examples. For this purpose we show how simple applications can be exposed as WSs, as well as deployed and registered at a service registry.

Using the simple WSs examples we introduce a procedure for development and deployment of BPEL process; we demonstrate this procedure, too.

The products comprising the platform we use in the practical part are Apache Tomcat Server, the Apache AXIS engine, and IBM's BPWS4j engine. The choice of the platform is put to discussion and arguments for and against it are considered.

Tutorial Structure
The tutorial starts with an overview representing shortly the structure and objectives of the tutorial.

The Theoretical Part introduces the WSs paradigm as an incarnation of the service-oriented architecture (SOA), the existing standards, specifications, implementations and tools for WSs and WSs-based process. We discuss the basic characteristics of the main WS protocols (HTTP, XML, SOAP, WSDL, and UDDI). Additionally, advanced concepts like WS composition and the respective specifications are considered in detail (e.g. BPEL4WS).

Using examples the Practical Part shows how WSs are being developed, deployed and registered. Building on the results of it the steps for development and deployment of BPEL processes are shown.

In the closing part conclusions are provided, and future trends and problems in the development of the web service technology are pointed out.

Background Knowledge

Participants are expected to have basic knowledge in XML and Java programming.
It is advisable but not a must to be familiar with Apache Tomcat Server and the AXIS engine. Some basic knowledge of web services and the foundations of workflow would additionally facilitate the comprehension of the practical examples.

Target Audience

This is an introductory tutorial to the Web Service paradigm. It is suitable for both researchers and practitioners, who would like to take a closer look at the specifics of the web services and web service-based applications.

Information about the speaker

Address

Dimka Karastoyanova, M.Sc.
Ph.D. Program "Enabling Technologies for the e-Commerce"
Darmstadt University of Technology, Germany

Hochschulstrasse 10, S2|02
D-64289 Darmstadt
Germany
e-mail: dimka@gkec.tu-darmstadt.de

web page:
http://www.informatik.tu-darmstadt.de/GK/participants/dimka/dimka.html
Telephone: +49 6151 16 6235
Fax: +49 6151 16 6229

Short Curriculum Vitae

Dimka Karastoyanova graduated from the University of Erlangen-Nuremberg, Germany, with a Master's degree in Computational Engineering.
Currently she takes part in the Ph.D. Program "Enabling Technologies for the e-Commerce" at the Technical University of Darmstadt, Germany. Her research topics include Web Services and Web Service Flows, Business Process modelling and management, e-Commerce, Database Systems, transactional support for Web Service-based applications.