Web Services Business Process Execution Language Research Articles

UML activity diagram transformation into BPEL integration flow

The growing interest of companies in integration and interoperability between information systems has caused increase in significance of Service-Oriented Architecture which provides tools for Enterprise Application Integration. In that architecture, Enterprise Service Bus provides technical possibilities of communication between IT systems. A key element in the communication are integration flows. Objective: The aim of this article is to present a new transformation Integration2BPEL, which automates the development of executable integration flow expressed in the Web Services Business Process Execution Language (WS-BPEL) based on the model of the integration flow presented in the Unified Modelling Language (UML) activity diagram. Method: The author proposes a transformation of the type of model-to-code type which generates integration flow expressed in WS-BPEL, which can be executed in any BPEL-compliant process engine. The integration flow is modelled using UML activity diagram with stereotypes from ‘UML Profile for Integration Flows’ profile in an IBM Rational Software Architect (RSA). Using Integration2BPEL transformation a complete, executable integration flow is generated, which is composed of many mediation mechanisms. Generated integration flows have been executed on OpenESB. Results: The ability to generate a complete integration flow in BPEL, which without any additions can be run on enterprise service bus. Implementation phase of an integration flow construction was automated. Each of integration flows is implemented according to the same rules. In addition, it allows to avoid mistakes made by designers and programmers. Conclusions: Model-Driven Development is an approach that leads to the automation of the design and programming phases. Integration2BPEL transformation is a uniform mechanism to design integration flow. Potentially, it also allows to avoid implementation errors. Keywords: Web Services Business Process Execution Language (BPEL), Enterprise Service Bus (ESB), Unified Modelling Language (UML), UML activity diagram, Model-Driven Development (MDD), Transformation. null

A path detecting method to analyze the interactive compatibility of service processes based on WS‐BPEL

SummaryPetri nets are frequently used formal tools to analyze the compatibility of interactive service processes described by Web Services Business Process Execution Language (WS‐BPEL). However, the traditional methods based on Petri nets were with a high computable complexity for state space explosion. To resolve such problem, a logic Petri net–based path detecting method for compatibility analysis of interactive service processes is proposed. From the provided mapping rules, the service process described by WS‐BPEL is modeled as a service net based on logic Petri nets. The evaluation of interactive compatibility of two service processes is converted to analyze whether their service nets can be composed as a non‐blocked synthetic service net. The non‐blocked property is checked by detecting the reachability of the potential connected paths in a service net. To reduce the complexity of computing the connected paths in a service net, we propose a merge‐reduced method to generate the path expression of its skeleton service net. The potential connected paths of a service net can be obtained by unfolding the path expression. Compared with the traditional method based Petri nets, the proposed method is with high efficiency and it can greatly alleviate the problem of state space explosion in analyzing interactive compatibility of service processes.

Modeling and Analysis of 3d Printing Ws-Bpel Business Processes Based on Servicenet

To solve the problem that whether the described Web service by business process execution language were interactive compatible, a method of WS-BPEL(Web Services Business Process Execution Language) parsing and execution was proposed. The service compatibility checking algorithm based on the Mediation model, which can provide multi-level service checking compatibility, and realize the goal of Service Cooperation or the demand of Value-Added Services. Based on BPMN specification, a task modeling and management tool was proposed to support the service components for assembly component. It supports both Web service automatic retrieval and service content analysis based on QoS information, and the task execution model between the BPMN specification task descriptions was transformed into the BPEL specification task description model. Finally, a model transformation strategy based on meta-model mapping was put forward. The algorithm was designed and examples were given to demonstrate the efficiency of 3D Printing WS-BPEL.

A novel programming framework for architecting next generation enterprise scale information systems

The increasing popularity and usage of internet based services makes design of software system complex and their power unlimited in scale. These systems often involve heterogeneous environment and platforms. They continuously evolve in order to meet the changes in technology and business practices. Emergence of information system architecture based on disparate externally provided internet based services warrant incorporation of novel design primitives in the application design. Traditionally popular application design primitives includes separation, abstraction, compression, uniform composition, replication and resource sharing that has evolved and came to vogue based on past experience and expert practice. This work examines and evaluates approaches to incorporation of new and novel unit operations around which applications can be architected, designed and analyzed for the internet computing and big data era. Incidentally it is found that portions of agent technology provides several unit operations such as migration of code and speech-act based responsibility delegation/application composition as application architectural primitives. This work determines extensions to Web Services-Business Process Execution Language (WS-BPEL) programming framework--called as ACtive Internet Application Framework (ACIAF) and is suited for incorporation of novel unit operations such as migration of code and speech-act based component orchestration/application composition to enable construction of next generation information systems. An analysis of merits and demerits of using WS-BPEL technology to realize ACIAF is also carried out here. Code mobility feature of ACIAF is demonstrated using a use case while loosely coupled application design using ACIAF is theoretically discussed. Formal analyzability of mobility behavior of ACIAF application is highlighted based on its conformance to Petri-net formalism. Further formal logical analyzability/interpolatability of individual actions performed by collaborating ACIAF applications is also highlighted. It is argued here that ACIAF shall provide necessary foundation, guidance and motivation for further detailed technical work on several ideas presented to realize next generation information systems. This work firmly establishes extension to WS-BPEL platform as a most viable approach to realize novel architectural primitives to the design and implementation of next generation information systems.

Building asynchronous geospatial processing workflows with web services

Geoscience research and applications often involve a geospatial processing workflow. This workflow includes a sequence of operations that use a variety of tools to collect, translate, and analyze distributed heterogeneous geospatial data. Asynchronous mechanisms, by which clients initiate a request and then resume their processing without waiting for a response, are very useful for complicated workflows that take a long time to run. Geospatial contents and capabilities are increasingly becoming available online as interoperable Web services. This online availability significantly enhances the ability to use Web service chains to build distributed geospatial processing workflows. This paper focuses on how to orchestrate Web services for implementing asynchronous geospatial processing workflows. The theoretical bases for asynchronous Web services and workflows, including asynchrony patterns and message transmission, are examined to explore different asynchronous approaches to and architecture of workflow code for the support of asynchronous behavior. A sample geospatial processing workflow, issued by the Open Geospatial Consortium (OGC) Web Service, Phase 6 (OWS-6), is provided to illustrate the implementation of asynchronous geospatial processing workflows and the challenges in using Web Services Business Process Execution Language (WS-BPEL) to develop them.

A model-driven approach to developing web service compositions based on BPMN4SOA

Several web service composition languages have appeared in the last years and converged into the Web Services Business Process Execution Language (WS-BPEL) standard. These languages are however quite complex and low level so that they cannot be used by non-programmers such as business users. To address these problems, various works proposed model-based approaches whereas other works focused on the transformation of business process models to executable languages such as WS-BPEL. However, there is a mismatch between these two levels and consequently, most existing mappings are limited and the respective tools can generate only primitive skeletons that require human intervention to complete a large part of the generated code. In this paper, we address the complexity of problems of executable service composition languages through a model-driven approach, in which we bridge the gap between the business level and the execution level by introducing an intermediate level for modelling service-based business processes using BPMN4SOA, which is our service-oriented extension of business process modelling notation for modelling service-based business processes.

AdaFF: Adaptive Failure-Handling Framework for Composite Web Services

In this paper, we propose a novel Web service composition framework which dynamically accommodates various failure recovery requirements. In the proposed framework called Adaptive Failure-handling Framework (AdaFF), failure-handling submodules are prepared during the design of a composite service, and some of them are systematically selected and automatically combined with the composite Web service at service instantiation in accordance with the requirement of individual users. In contrast, existing frameworks cannot adapt the failure-handling behaviors to user's requirements. AdaFF rapidly delivers a composite service supporting the requirement-matched failure handling without manual development, and contributes to a flexible composite Web service design in that service architects never care about failure handling or variable requirements of users. For proof of concept, we implement a prototype system of the AdaFF, which automatically generates a composite service instance with Web Services Business Process Execution Language (WS-BPEL) according to the users' requirement specified in XML format and executes the generated instance on the ActiveBPEL engine.

Performance Analysis of Service Oriented Software

Web Services Business Process Execution Language (WS-BPEL) is a promising language describing the Service Oriented Software (SOS) orchestrations in form of Business Processes (BP), but it lacks of a sound formal semantic, which hinders the formal analysis and verification of business processes specified in it. Formal methods, like Petri Nets, may provide a means to analyse WS-BPEL processes, evaluating its performance, detecting weaknesses and errors in the process model already at design-time. This article addresses quality of SOS orchestrations created using the WS-BPEL and a framework ”SOASPE” for transformation of WS-BPEL into Generalized Stochastic Petri Nets is proposed to analise the performance and throughput of SOS, based on the execution of orchestrated processes.

IQoS-aware exception resolution for BPEL processes: a middleware-based framework and performance evaluation

Web Services Business Process Execution Language (WS-BPEL) is widely used nowadays for specifying and executing composite business processes. During the execution, however, of such business processes, a number of faults stemming from the nature of SOA may occur. The WS-BPEL scenario designer must therefore use the provisions offered by WS-BPEL to catch these exceptions and resolve them. The system fault handler specification, however, is an additional task for the WS scenario designer, while the presence of such handlers within the scenario necessitates extra maintenance activities. In this paper, we propose a middleware-based framework for system exception resolution, which undertakes the tasks of failure interception, discovery of alternative services and their invocation. The process of selecting the alternative services can be driven by process consumer-specified Quality of Service (QoS) policy. Moreover, the middleware arranges for bridging syntactic differences between the originally invoked services and functionally equivalent replacements to it, by employing XSLT-based transformations. The middleware is deployed and maintained independently of the WS-BPEL scenarios, thus removing the need for specifying and maintaining system fault handlers within the scenarios. We also present performance measures, establishing that the overhead imposed by the addition of the proposed middleware layer is minimal.

A Petri Net-Based Method for Compatibility Analysis and Composition of Web Services in Business Process Execution Language

Automatic Web service composition is gaining momentum as the potential silver bullet in service oriented architecture. The need for interservice compatibility analysis and indirect composition has gone beyond what the existing service composition/verification technologies can handle. Given two services whose interface invocation constraints are described by a Web services-business process execution language (WS-BPEL or BPEL), we analyze their compatibility and adopt mediation as a lightweight approach to make them compatible without changing their internal logic. We first transform a BPEL description into a service workflow net, which is a kind of colored Petri net (CPN). Based on this formalism, we analyze the compatibility of two services, and then devise an approach to check whether there exists any message mediator so that their composition does not violate the constraints imposed by either side. The method for mediator generation is finally proposed to assist the automatic composition of partially compatible services. Our approach is validated through a real-life case and further research directions are pointed out.

Business Process Standards – Current Landscape (Landkarte aktueller Standards zur Beschreibung von Geschäftsprozessen: WS-BPEL, BPEL4People, BPEL-SPE, BPELJ, SCA)

Summary The landscape of current specifications for the description of business processes consists of the Web Services Business Process Execution Language (WS-BPEL) as an adopted standard, and a number of functional extensions allowing for human interactions (BPEL4People), sub-processes with life-cycle coupling (BPEL-SPE), and Java integration (BPELJ). Also relevant for the assembly of portable, executable applications is the Service Component Architecture (SCA) which provides a model for service-based components complementing WS-BPEL. This paper provides an overview of the current business process standards landscape and its further evolution.

Analysis of security‐relevant semantics of BPEL in cross‐domain defined business processes

PurposeAims to identify security‐relevant semantics of business processes being defined by WS‐BPEL (Web Services Business Process Execution Language, BPEL for short) scripts, in particular, when such scripts defining collaborative business processes on top of web services are deployed across security domain boundaries.Design/methodology/approachAnalysing potential of BPEL to define behaviour of business processes violating restrictions implied by security policies.FindingsSemantic patterns being combinations of particular BPEL features and web services with specific access restrictions implied by security policies are defined and their implications for analysis of BPEL scripts during compliance assessment of cross‐domain defined business processes are identified.Research limitations/implicationsThe results of the research part of which is reported here have been applied in a research prototype to BPEL scripts of limited size and comparatively simple business logic. Real‐world examples of BPEL scripts with respect to size and complexity should be examined for further approving suitability of the algorithms used.Originality/valueThe results can be used to specify security policies in terms of security‐critical semantics of BPEL scripts in order to facilitate compliance assessment. In conjunction with other results of this research, this will help to overcome security issues arising from cross‐domain definition of business processes by enabling automatic compliance assessment prior to execution.