Abstract

The objective of this research work is to look into the role of policies and context in framing the composition of Web services. Context supports the development of adaptable Web services and policies specify the behavior of Web services engaged in composition. In this paper, we present this research work’s outcome, namely a context-based multi-type policy for Web services composition in which the binding between Web services occurs at four levels: component level to deal with Web services’ definitions and capabilities, composite level to address how Web services are discovered and combined, semantic level to handle the semantic heterogeneity that can arise between Web services, and resource level to focus on the performance of Web services. Because of the composition complex-nature, the proposed approach uses three types of policies: engagement policies assess a Web service participation in a given composition, mediation policies deal with the semantic heterogeneity by tacking into account the mappings and conversions between component Web services, and deployment policies manage the interactions between component Web services and computing resources. Policies manage the transitions between the four levels and context caters the necessary information that tracks the composition progress.

Keywords: Composition; Context; Exception; Policy; Web service

Article Outline

1. Introduction

1.1. Preliminaries and motivations

1.2. Contributions

1.3. Paper organization

2. Related work

2.1. Context for Web services

2.2. Policies for Web services

3. The context-based multi-type policy approach

3.1. Approach presentation

3.2. Description of -levels

3.2.1. The -Component level

3.2.2. The -Composite level

3.2.3. The -Semantic level

3.2.4. The -Resource level

3.3. Description of -contexts

3.4. Description of policies

4. Structure of contexts

5. Web services and policies

5.1. Impact of policies on Web services

5.2. Specification of policies

Engagement policy

5.2.1. Mediation policy

5.2.2. Deployment policy

6. Exception handling

6.1. Rationale and motives

6.2. Exceptions per policy type

7. Implementation

8. Conclusion

References

Vitae