系统中英文对照外文翻译文献
中英文对照外文翻译
(文档含英文原文和中文翻译)
Modeling and specification of Web services composition using
UML-S
Abstract
As Web services composition arouses a growing interest, most research works address implementation and execution issues. Therefore, many composition languages (BPEL, XLANG, WSFL, WSCI, to name a few of them) have been proposed in the past few years. However, a weakness of these languages is that they are difficult to use in early stages of development, such as specification. In this paper, an extensio n to UML 2.0 called ”UML-S: UML for Services” is introduced. UML-S allows for a Model Driven Engineering (MDE) of Web services and their interactions.
1. Introduction
Many companies are now using the Web as a platform to communicate with their partners. The Web and its technologies allows them to provide Web services to individuals as well as other businesses.
The main challenges in the Web services paradigm are their discovery and their composition. In other words, one must be able to find a suitable Web service for a given task. This process is called the discovery [18, 19]. The second challenge is the one that is addressed in this paper. It is known as Web services composition [4, 10]. In Web services composition, already defined services are used together to achieve a larger task, resulting in a new composite and value-added Web service. To accomplish this purpose, a common approach is to allow the Web services to interact in a scenario through the use of messaging mechanisms.
Although a lot of research works deal with Web services interactions, most of them address language, implementation or application issues, neglecting early stages of the de
velopment process, such as specification. To address this issue, an extension to UML 2.0 called ”UML-S: UML for Services” is introduced. UML-S allows for modeling Web services as well as their interactions.
The Unified Modeling Language (UML) has been defined by the Object Management Group (OMG) [2] to express graphically system development models.
UML-S enables the developers to build composite Web services by following the principles of the Model-Driven Architecture (MDA). As a consequence, it is possible to generate platform-specific code from high-level UML-S models.
This paper is structured as follows. Section 2 provides a survey of existing approaches to model Web services interactions. In section 3, the requirements for a good Web services composition modeling language are put forward. UML-S is then presented in details in section 4. After that, a case study is provided in section 5 to observe UML-S in action. Finally, section 6 draws the conclusions and presents future work.
2.Related Work
The Business Process Management Initiative (BPMI) has developed the Business Process Modeling Notation (BPMN). This notation is particularly useful to visualize BPEL processes.BPMN [23] is now maintained by the OMG. Unfortunately, one could reproach to
BPMN its lack of formalism, as explained by Wohed et at. in [24]. Although BPMN is an interesting solution, we preferred to extend UML 2.0 to achieve the same purpose. Indeed, UML was already used as a Process Modeling Language (PML) [9, 13, 16].As a matter of fact, UML has some very interesting features as a PML: it is standard, graphical, popular and it contains several diagrams which allows to model different views of a system.
UML was already considered to describe Web services composition. In [20], an approach using UML activity diagrams to do so was presented by Skogan et al.They provide a way to model the coordination and the sequencing of the interactions between Web services. They also explain how UML activity diagrams can be converted into BPEL [1] or in WorkS
Co [3].However, in this approach, methods input/output and data transformation are modeled in notes (i.e. comments) on the side of the workflow, which can get quite confusing when the composition flow gets complex.
Chunming Gao et al. also present in [11] a non-graphical way to model Web services composition with some mobility and time constraint. To do so, they introduce Discrete Time Mobile Ambient calculus (DTMA), an extension to the formal model called Mobile ambients calculus [5]. Using DTMA, they focus on modeling BPEL operations. Due to their non-graphical nature, languages such as DTMA are less user-friendly than graphical like UML.
Another approach to Web services composition modeling was proposed by De Castro et al in [6]. In their work, they make use of the behavior modeling method of MIDAS, a Model-Driven Architecture (MDA) framework [14]. MIDAS is a model-driven methodology for the development of Web Information Systems (WIS) based on the MDA [21], proposed by the OMG [2]. They introduced Web services composition through UML activity diagram
s in their paper. However, the model is not detailed as much as necessary to allow code generation as BPEL. Some features could also be added such as data transformation and flow control mechanisms.

版权声明：本站内容均来自互联网，仅供演示用，请勿用于商业和其他非法用途。如果侵犯了您的权益请与我们联系QQ:729038198，我们将在24小时内删除。