Asynchronous Modeling and Implementation of Web Services Based on JMS

Context-awareness is gaining wide importance, especially when targeting pervasive environments, whereas Web Services are often exploited as building blocks of context-aware applications because of their interoperability properties. In this framework, Web Services can be used as business services requiring context data for their functionality, but also as context sources offering access to context information. Combining the development of context-aware Web Services with Model-Driven Engineering techniques requires the identification and matching of appropriate context models with Web Service models. In this paper, a new ongoing research direction is presented, which refers to model transformation for allowing the identification of appropriate context sources and ensuring their compatibility with Web Services. Matchmaking principles between Web Service and context models are examined in order to extract a reasoning mechanism on context adaptation compatibility. In specific, the principles of graph transformation are mainly exploited.

To solve workflow engines inter-operation each other, and achieve information interaction among distributed engines, this paper presents an inter-operation model among distributed workflow engines based on Shark and Asynchronous Web Services. Inter-operation model interface among workflow engines regards as service resources provided by Web Services, and uses observer design pattern and extensible markup language SOAP protocol as inter-operation communication mechanism, and regards inter-operation service provided by Web Services as external applications, to implement inter-operation among distributed workflow engines. The model used to achieve the J2EE platform distributed workflow engine dynamic interoperation and achieve a goal of Enterprise Application Integration.

Service-oriented computing (SOC) strives for applications having services as the fundamental element of design, and Web services acting as the enabling technology. Web services use open, XML-based standards and are becoming the most important technology for communications between disparate applications in different enterprises. In this paper, the authors study end-to-end response time for synchronous and asynchronous composite Web services invoked over the Internet. The main aim is to study the queuing time and execution time for various classes of clients present in a system. the authors present a formal model based on queuing network to simulate the execution time for composite Web services, which require different blend of services and need different set of resources to execute.

The automatic composition of Web services requires the existing services to be encoded in a semantic form, such as ontology. If Web services are represented with ontology, we can automatic compose Web services by means of their semantics. Ontology modeling is divided into two steps: input/output parameters modeling and Web services modeling. First, we collect Web services' input/output parameters, represent them with classes in ontology, and transform Web services to properties in ontology, define relations between classes and properties. Then we judge Web services' relations based on relations between properties transformed from these Web services and estimate whether these Web services can be composed.

Preface. 1. Introduction. 1.1 What is COP? 1.2 Why is COP important? 1.3 What is a component? 1.4 Hardware components and software components. 1.5 From OOP to COP. 1.6 Component-based software engineering. 1.7 Summary. 1.8 Self-review questions. 1.9 Exercises. 2. A Theory of Components. 2.1 Principles of COP. 2.2 Infrastructures of COP. 2.3 Component models. 2.4 Connection models. 2.5 Deployment models. 2.6 Unifying component technologies. 2.7 Summary. 2.8 Self-review questions. 2.9 Exercises. 3. COP with JavaBeans. 3.1 Overview of JavaBeans technology. 3.2 The component model of JavaBeans. 3.3 The connection model of JavaBeans. 3.4 The deployment model of JavaBeans. 3.5 Examples and lab practice. 3.6 Summary. 3.7 Self-review questions. 3.8 Exercises. 4. Enterprise JavaBeans Components. 4.1 The EJB a rchitecture. 4.2 The component model of EJB. 4.3 The connection model of EJB. 4.4 The deployment model of EJB. 4.5 Examples and lab practice. 4.6 Summary. 4.7 Self-review questions. 4.8 Exercises. 4.9 Programming exercises. 5. CORBA Components. 5.1 The COBRA component infrastructure. 5.2 The CORBA component model (CCM). 5.3 The connection model of CORBA and CCM. 5.4 The deployment model of CORBA and CCM. 5.5 Examples and lab practice. 5.6 Summary. 5.7 Self-review questions. 5.8 Exercises. 5.9 Programming exercises. 6. .NET Components. 6.1 The .NET framework. 6.2 The component model of .NET. 6.3 The connection model of .NET. 6.4 .NET component deployments. 6.5 Visual Studio .NET. 6.6 Examples and lab practice. 6.7 Summary. 6.8 Self-review questions. 6.9 Exercises. 6.10 Programming exercises. 7. COP with OSGi Components. 7.1 Overview of OSGi technology. 7.2 The component model of OSGi. 7.3 The connection model of OSGi. 7.4 The deployment model of OSGi. 7.5 Examples and lab practice. 7.6 Summary. 7.7 Self-review questions. 7.8 Exercises. 8. Web Services Components. 8.1 The Web Services framework. 8.2 The component model of Web Services. 8.3 The connection model of Web Services. 8.4 Web Services component deployment. 8.5 Examples and lab practice. 8.6 Summary. 8.7 Self-review questions. 8.8 Exercises. 8.9 Programming exercises. Appendix.

The increasing popularity of Web services for application integration has strengthened the need for automated Web service composition and joint execution. A lot of attention has been paid recently towards techniques for creating a composite Web service from individual Web services based on user requirements, and driven by a variety of criteria. However, the major lacuna so far in Web service composition is the lack of a holistic requirements-driven approach for modeling the Web service execution lifecycle. In this paper we present such an approach based on our earlier work on context-driven Web service modeling. In particular, we separate requirements into two parts - functional and extrafunctional requirements (FRs and EFRs, respectively). We express FRs as commitments made by individual Web ser-vices towards the composite Web service, and EFRs as rules that constrain the behavior of the individual Web services while they execute against their FRs. We also present a conceptual model that can be used for tracking requirements during Web service execution.

The article describes a method for developing and modelling composite web-services. Web-service composition is used to derive new functionality from the interaction of existing web-services. Composite web-services are built in several stages: specifications (determining the type of service); development of the structure of the service based on the algebra of services; service composition modelling; selecting a service variant and generating a service. The main elements of the proposed approach are the algebra of services and web-services interaction models (basic and composite). The above approach formally presents the consideration of the main aspects in solving problems related to the construction of effective composite web-services and the selection of mathematical models, namely: description of web-services, determining the structure of web-services, taking into account the dynamics of information changes, taking into account the main uncertainties in building the structure web-services. Based on the approach, a method for constructing composite web-services has been developed. The method is based on an algebraic description of a web-service based on a specialized algebra of services. The method consists of the following steps: description of the task of developing a web-service; development of the structure of a web service based on the algebra of services; formal description of the structure and clarification of service operations; building models of functioning and interaction of service components; building simulation models of the composite service; defining the final structure of the composite service; web-service implementation. The main tool for describing composite services is the algebra of services, and the model building tool is colouredPetri nets implemented using СPN Tools. As an example of the application of the developed method, the construction of a pharmaceutical service is described, in which the modellingof the interaction of web-services based on Petri nets is used. The process of building a composite model of a web-service is considered. The process begins with building a pharmaceutical web-service model structure based on the service algebra. Based on the service algebra, operators were developed to implement composite services. The structure of the model is developed, which is presented in the form of a formal description. The process of building pharmaceutical service models in the СPN Tools environment is described in detail.

Web services form the core of e-business and hence, have experienced a rapid development in the past few years. This has led to a demand for a discovery mechanism for Web services. Discovery is the most important task in the Web service model because Web services are useless if they cannot be discovered. A large number of Web service discovery systems have been developed. Universal Description, Discovery and Integration (UDDI) is a typical mechanism that stores indexes to Web services but it does not support semantics. Semantic Web service discovery systems that have been developed include systems that support matching Web services using the same ontology, systems that support matching Web services using different ontologies, and systems that support limitations of UDDI. This paper presents a survey of Web service discovery systems, focusing on systems that support semantics. The paper also elaborates on open issues relating to such discovery systems. Request access from your librarian to read this chapter's full text.

Matching web services and client requirements in the form of goals is a significant challenge in the discovery of semantic web services. The most common but unsatisfactory approach to matching is set‐based, where both the client and web services declare what objects they require and what objects they can provide. Matching then becomes the simple task of comparing sets of objects. This approach is inadequate because it says nothing about the functionality required by the client or the functionality provided by the web service. As an alternative, we use the Frame Logic as implemented in Flora‐2 to specify web service capabilities and client requirements, including their preconditions, postconditions, and ontologies, implement a logic‐based discovery agent using Flora‐2, demonstrate its usefulness in a medical appointment making scenario, and show its efficiency both theoretically and by benchmarking. The result is an expressive yet concise representation scheme for semantic web services, and a practical, efficient, powerful, and fully implemented matching engine based purely on logical inference for web service discovery, with direct applicability to Web Service Modeling Ontology and Web Service Modeling Language, because both are based on Frame Logic.

While Web service models become increasingly popular and many service providers start to offer all kinds of Web services, the quality of service (QoS) for Web services has become an important factor for service requesters to consider during the selection process of appropriate Web services. In this paper, we present an evaluation and selection framework (CosmosQoS) for QoS-required Web services. A novel architecture and reputation appraisal model to monitor, store and evaluate the physical usage and post-condition of requested Web services in a requester-located network is proposed to better support service requesters such that they can select suitable Web services based on their QoS requirements, trustworthiness of Web services, and effect of network connection and configuration between service requesters and providers.

Web services form the core of e-business and hence, have experienced a rapid development in the past few years. This has led to a demand for a discovery mechanism for web services. Discovery is the most important task in the web service model because web services are useless if they cannot be discovered. A large number of web service discovery systems have been developed. Universal Description, Discovery and Integration (UDDI) is a typical mechanism that stores indexes to web services but it does not support semantics. Semantic web service discovery systems that have been developed include systems that support matching web services using the same ontology, systems that support matching web services using different ontologies, and systems that support limitations of UDDI. This paper presents a survey of web service discovery systems, focusing on systems that support semantics. The paper also elaborates on open issues relating to such discovery systems.

The wide deployment of Web services in wire line and wireless networks has resulted in the proliferation of user identities relying on which the trust between a user and a Web service can be established through identification and authentication. Since user identities normally contain some information concerned with user privacy, sharing of such identity information between Web services should be minimized to preserve user privacy. In this paper, we propose a user-centric trust model for supporting Web services based on the principle of least sharing identity information. This model can be applied to applications in which a user is interacting with multiple Web services simultaneously. We describe this model and show how it can be used as the foundation for developing comprehensive solutions to protect user identities during Web service interactions, thus preserving user privacy.

Context-aware web services have been attracting significant attention as an important approach for improving the usability of web services. In this paper, we explore a novel approach to model dynamic behaviors of interacting context-aware web services, aiming to effectively process and take advantage of contexts and realize behavior adaptation of web services and further to facilitate the development of context-aware application of web services. We present an interaction model of context-aware web services based on context-aware process network (CAPN), which is a data-flow and channel-based model of cooperative computation. The CAPN is extended to context-aware web service network by introducing a kind of sensor processes, which is used to catch contextual data from external environment. Through modeling the register link's behaviors, we present how a web service can respond to its context changes dynamically. The formal behavior semantics of our model is described by calculus of communicating systems process algebra. The behavior adaptation and context awareness in our model are discussed. An eXtensible Markup Language-formatted service behavior description language named BML4WS is designed to describe behaviors and behavior adaptation of interacting context-aware web services. Finally, an application case is demonstrated to illustrate the proposed model how to adapt context changes and describe service behaviors and their changes.

The recent approaches for Web services composition tend to integrate heterogeneous business processes executed in Peer-to-Peer networks. In such networks, component Web services are invoked on independent peers and are orchestrated according to the transactional requirements defined by the designers or the users of the composite Web service. Since component Web services can be dynamically invoked and are generally implemented as black boxes, concurrency between them may appear. This paper presents the transactional execution model of composite Web services exploiting the transactional properties of their component Web services. The proposed concurrency control is ensured by a decentralized serialization graph based on an optimistic protocol and on the hierarchical structure of the composition. The globally correct execution of the composite Web service is achieved by communication among dependent subtrans-actions and the peers they have accessed.

<span>Web services' high levels of duplicate textual structures have caused network bottlenecks and congestion. Clustering and then aggregating similar web services as one compressed message can potentially achieve network traffic reduction. In this paper, a static Hilbert clustering as new model for clustering web services based on convex set similarity is proposed. Mathematically, the proposed model calculates similarity among simple object access protocol (SOAP) messages and then cluster them based on higher similarity values. Next, each cluster is aggregated as a compact message. The experiments have explained the proposed model performance as it has outperformed the convention clustering strategies in both compression ratio and clustering time. The best results have been achievable by the proposed model has reached up to (15) with fixed-length and up to (21) with Huffman.</span>