Generating Request Web Services from Annotated BPEL

Web services technology is the most common implementation of service oriented architecture. Web services are based on open technologies such as eXtensible Markup Language (XML) and offer a distributed approach for the integration of heterogeneous applications across the internet. The process of combining web services functionalities into one composite service is called web services composition. To perform this task, several languages such as Business Process Execution Language (BPEL), Web Services Flow Language (WSFL) and Web Service Choreography Interface (WSCI) have emerged. These languages are based on programming concepts and neglect the specification step which is very important in any software development process. In this paper, we address the formal specification of web services descriptions and the modelling of their composition using the model driven engineering principles. To this end, we propose a domain specific language (DSL) called S-GNet. The proposed DSL introduces new modelling elements which make it well adapted to the web services characteristics. We also propose a graph grammar which transforms Web Services Description Language (WSDL) descriptions into their equivalent S-GNet specifications. This grammar is integrated within an S-GNet modelling tool.

The Business Process Execution Language (BPEL) has become the standard in Web service composition, so that been adopted by industries to create mission critical services. The business process reliability especially business process consistency when some services failed is critical to composite services especially involving various organizations. However, it is difficult to conduct business process reliability testing for composite services due to complex business process in service composition, remote deployed services and long time testing duration. Little research is done to test fault tolerance capabilities of composite services only from low level. This paper proposes a technique on how to test the reliability of composite service defined in BPEL from the view of business semantics with little cost using fault injection. We present an approach for reliability testing of web services by using service stubs with semantic faults instead of real services which can be placed at service provider side or service consumer side. Dislike existing studies, we focus on how to find the reliability problems associating with business process - called semantics as the problems are not pure coding error but faults related to business process. In addition, the behavior of composite services in BPEL is analyzed when there are faults in orchestrated services invoked. Finally, a case study is given to show the whole process of reliability testing for composite web service.

Service Oriented Architecture (SOA) has been widely used during the past decade due to its ability to seamlessly integrate various applications developed using different technologies. Web services based on open standards are the most commonly used technology to realize an SOA. Business processes are executed by appropriate orchestration of various services from different departments that belong to a single organization or from multiple organizations. Security is an important quality attribute that has to be built into any application that is developed using SOA. XML is the underlying technology for Web Service Description Language (WSDL), SOAP protocol and Business Process Execution Language (BPEL). It is highly probable that an attacker could inject malicious information into these XML files to modify the flow of the business process. Further, SOAP was not designed with security in mind, it is possible to tamper the SOAP messages while they are in transit. There exist a number of such potential vulnerabilities which lead to possible security breach in the individual services. In an orchestrated business process, there are possibilities of more vulnerabilities. One of the existing tools namely WS-Attacker is only capable of testing the security of individual web services alone. In spite of the widespread usage of SOA, currently there is limited automatic tool support for testing the security provided by an entire SOA application involving service orchestration. In this context, this paper focuses on designing and implementing a plug-in for WS-Attacker to analyze a few security vulnerabilities present in SOA business processes.

The Business Process Execution Language (BPEL) is now a de facto standard for specifying and executing business process for web service composition and orchestration. As more and more web services are composed using BPEL, tuning these compositions and gain better performance becomes increasingly important. This paper presents our approach for optimizing the BPEL process and introduces OptBPEL, a tool for performance optimization of BPEL process. The approach starts from the optimization of synchronization structure concerning link in BPEL. After that, some concurrency analysis techniques are applied to obtain further performance improvement. Finally, we give some experiments and prove the efficiency of these optimization algorithms used in OptBPEL.

RESTful Web service composition with BPEL for REST

Testing service orchestrations is a challenging research domain due to necessity of additional testing efforts, complementing traditional software testing. Although various testing approaches and tools have been proposed, most of them provide partial solutions covering single testing activities such as test path analysis, test case generation, Web service emulation, fault injection and so on. Following the current research direction, we have developed an integrated testing framework, called TASSA, which aims to provide end-to-end testing of Business Process Execution Language (BPEL) orchestrations. This paper introduces its core capability for automation of test cases generation, execution and management implemented in an open source tool for WSDL-based testing of both single Web services and composite Web services, described with BPEL. The tool's functionality includes identification of web service operations as well BPEL variables in case of service composition testing, generation of SOAP request templates, data driven testing, definition of assertions at different levels (HTTP, SOAP and BPEL variable), execution and management of test cases.

Summary form only given. This poster presents an experience, on gathering business needs in business models adapted to the business expert language and translating these needs into a service oriented architecture (SOA) in a systematic way. The poster introduces the current situation highlighting three interoperability problems: (1) Organisations do not use a standard, unified and widely adopted business process definition language. Organisations want a common understanding of the process where they are involved from different perspectives; (2) Information systems are implemented to address specific requirements, ignoring future integration needs by using proprietary formats, and ad-hoc communication strategies and protocols; and (3) Information systems do not, clearly, support the business processes. There is a gap between business process models and their information systems implementations. The approach shown in this poster is based on the usage of the SOA paradigm from a model driven point of view: a model driven service oriented architecture (MDSOA) framework. Based on the MDA specification we have identified a metamodel for each of the three abstraction levels: (1) POP* (process, organisation, product) is selected as the metamodel to represent and exchange business processes. POP* is the unified enterprise modelling language (UEML) successor. POP* metamodel represents the starting point; (2) PIM4SOA (platform independent model for service oriented architecture) (Benguria et al., 2006) is a metamodel to represent service, process, information and quality of service elements; and (3) WSDL (Web service description language) and BPEL (business process execution language) are platform specific languages

The Business Process Modeling Notation (BPMN) was developed by an international body called the Business Process Management Initiative (BPMI). The strengths of BPMN include that it is easily readable and understandable, and could be transformed into the current widely used business process implementation language, the Business Process Execution Language (BPEL). However, there are some fundamental incompatibilities between BPMN and BPEL, which make it difficult to generate BPEL code for implementation from BPMN models.The aim of this paper is to investigate the synergic uses of BPMN and BPEL to model and implement executable business processes. To that end, we propose a Business Process Modelling framework. Then we apply it to a real life business process scenario involving a typical manufacturing process in the automotive industry. From the case study, we are able to conclude that BPMN is suitable for modelling business processes and then implementing the model in BPEL in spite of the incompatibilities between the former and the latter.

An emerging technology like business process execution language (BPEL) and its implementation in BPEL for Web services (BPEL4WS) gives extra possibilities in describing business processes. It further adheres, as a technology, in a consistent way to the underlying Web service-based implementation technology and is a perfect fit for service-oriented architectures (SOA) as they are currently implemented throughout organizations as a successor to enterprise application integration (EAI). However, BPEL4WS, in its current implementation, will only serve in a static way for production workflows. In this chapter we discuss how Semantic Web services through a semantic service-oriented architecture (SSOA) can be used to extend BPEL4WS to create ad hoc and collaborative workflows.

The concept of software as a service has been increasingly adopted to develop distributed applications. Ensuring the reliability of loosely coupled compositions is a challenging task because of the open, dynamic, and independent nature of composable services; this is especially true when the execution of a service-based process relies on independent but correlated services. Transactions are the prototypical case of compositions spanning across multiple services and needing properties to be valid throughout the whole execution. Although transaction protocols and service composition languages have been proposed in the past decade, a true viable and effective solution is still missing. In this article, we propose a systematic aspect-based approach to integrating transactions into service compositions, taking into account the well-known protocols: Web Service Transaction and Business Process Execution Language (BPEL). In our approach, transaction policies are first defined as a set of aspects. They are then converted to standard BPEL elements. Finally, these transaction-related elements and the original BPEL process are weaved together, resulting in a transactional executable BPEL process. At runtime, transaction management is the responsibility of a middleware, which implements the coordination framework and transaction protocols followed by the transactional BPEL process and transaction-aware Web services. To automate the proposed approach, we developed a supporting platform called Salan to aid the tasks of defining, validating, and weaving aspect-based transaction policies, and of deploying the transactional BPEL processes. By means of a case study, we demonstrate the proposed approach and evaluate the performance of the supporting platform. Experimental results show that this approach is effective in producing reliable business processes while reducing the need for direct human involvement.

This paper describes a method for the implementation and optimization of business processes in a service oriented architecture (SOA). A process specification is created by business people, and expressed in Business Process Modeling Notation (BPMN). The specification is then translated into Business Process Execution Language (BPEL), and used by technical people as a reference process, which is subject to a series of transformations that change the internal process structure in order to improve the quality of the process execution. The behavior of each transformed process is verified automatically against the behavior of the reference process. The verification mechanism is based on a mapping from BPEL to Language of Temporal Ordering Specification (LOTOS), followed by a comparison of the trace set that is generated using a program dependence graph of the reference process and the trace set of the transformed one. When the design goals have been reached, the transformed BPEL process can be executed on a target SOA environment using a BPEL engine.

In this paper, we present a service-oriented architecture (SOA) based system to meet the on-demand VMI requirements. SOA is used to create flexible and efficient loosely-coupled systems . We utilize technologies including web services, SOAP, HTTP, XML and WSDL to develop a VMI system. Web services can support the integration of information and services across platforms and operating systems. In addition, we implement web service coordination (WS-Coordination) to enable coordinated transactions across platforms. WS-Coordination is a specification for providing protocols that coordinate the actions of distributed applications. Also, we present workflow of VMI operations from two aspects: seller¿s market and buyer¿s market. Finally, we use the business process execution language (BPEL) for web services to describe business processes of VMI. Service components are deployed flexibly in web environment using the Apache Axis2 web services engine.

There are often three groups of experts involved in the design and implementation of business processes in a service oriented enterprise; business analysts, solution architects and system developers. They collaborate with each other to transform a high-level design created by a business analyst to a final executable workflow, based on a service composition language such as the Business Process Execution Language (BPEL). In this paper, we present a new approach to support and semi-automate this transformation process, thus producing applications of higher quality in shorter time. The idea is to capture existing knowledge in the enterprise, which is required for transforming models from one abstraction level to another, as reusable, parameterized patterns. These patterns are used for tool based model transformations of the business processes. To support our approach, we shall make use of Domain Specific Modeling Languages (DSMLs) designed for each enterprise to capture models of a business process at different levels of abstraction, each suitable for the use of one of the groups of experts. The presented approach bridges the gap between business and IT by providing customizable language-, tool- and transformation support for the different groups of experts within the enterprise and is illustrated by an example.

We define an abstract operational model of the Business Process Execution Language for Web Service (BPEL4WS) based on the Abstract State Machine (ASM) formalism. That is, we abstractly model dynamic properties of the key language constructs through the construction of a Business Process Execution Language (BPEL) abstract machine. Specifically, we present the process execution model and the underlying execution lifecycle of BPEL activities. The goal of our work is to provide a precise and well defined semantic framework for establishing the key language attributes. To this end, the BPEL abstract machine forms a comprehensive and robust formalisation closely reflecting the view of the informal language definition.

Web service composition refers to the process of combining several value-added services. It has received much interest in enterprise applications. Web Service Choreography Description Language (WSCDL) is a W3C specification for the description of peer-to-peer collaborations of participants from a global viewpoint. As an XML-based language aimed to become a Web service composition standard for choreography, WSCDL may clarify the opaque points, detect and repair design errors in the language definition, yet provide the theoretical grounding for relative tools development. Petri net is a first-class formal modeling tool that has been widely used in many fields. Based on a Petri net, this paper proposed a formal model that can be used to clarify the semantics of WSCDL and verify some relative properties throughout. The model helps analyze the semantic compatibility between a business process specified in Business Process Execution Language (BPEL) and a WSCDL process.