Service orchestration languages, like the Web Services
Business Process Execution Language (BPEL), have been
frequently used to provide an implementation platform for
model-driven development approaches. As avoidance of
vendor lock-in and portability of process definitions are
central aims of BPEL, most approaches claim to support
a large set of different runtime environments. But, even
though today various runtimes for BPEL are available, every runtime implements a different language subset, thus
hampering portability. Our idea is to improve this situation by using techniques, the Web Services Interoperability
Organization (WS-I) has used to improve services interoperability. We describe a portability profile for BPEL that
can detect portability issues in process definitions. Using
this profile, we evaluate the portability of BPEL mappings
used in several model-driven development approaches.
Process languages such as the Business Process Model and Notation 2.0 or the Web Services Business Process Execution Language promise the portability of executable artifacts among different runtime environments, given these artifacts conform to the respective specification.
However, due to the natural imperfectness and differing priorities of runtime environments, actual portability of process code is often hard to achieve. A first step towards tackling this problem is the quantification of the actual degree of portability of process code using software metrics. The ISO/IEC 25010 software quality model defines portability as a main software quality characteristic with several sub-characteristics. One of these is adaptability, the degree to which a piece of software can be adapted in order to be executed in a different environment. In this paper, we propose a mechanism for quantifying the degree of adaptability of BPMN 2.0 processes and demonstrate its computation.
Service-oriented software consists of middleware, such as application servers and runtime engines, into which service applications are deployed. This middleware is often complex and difficult to install. The deployment of services requires the crafting of deployment descriptors and packaging
of applications. As a consequence, the installation of service-oriented software systems can be a daunting task. Installability, however, is an important influencer of the portability of software. Portability in turn is one of the main goals of service orchestration languages based on open standards. In this paper, we investigate the installability of service orchestrations based on the
Systems and software Quality Requirements and Evaluation
(SQuaRE) method, the new series of software qual-
ity standards currently under development by the ISO/IEC.
We develop a measurement framework based on SQuaRE and
tailored to evaluating the installability of service orchestrations and their runtimes. We validate the measurement framework theoretically and show its applicability in a case study.
Business Process Model and Notation (BPMN) 2.0 process models are used more and more, both in practice as in academia. Although academic research mainly
focuses on sophisticated semantic checks and extensions there still exist problems in the basic usage of BPMN. This paper investigates issues in BPMN model serializations which arise as a result of the complexity and inconsistency of the standard document. We present a set of serialization constraints as a starting point for sophisticated compliance checks on serialized BPMN models. Furthermore, these constraints are used to perform an evaluation of current modeling tools. This evaluation reveals that the creation of standard compliant models is still a non-trivial endeavor.
Correct and standard compliant serializations of BPMN process models are crucial for model exchange between tools, automatic application of academic verification approaches and executability on BPMN engines. The official standard document does not provide an extensive set of all constraints regarding the correctness of model serializations. This technical reports fills this gap by presenting a categorized list of generic, technology independent constraints stated by the standard. Furthermore it is analyzed which rules are already covered when the standardized XSD-based serialization format is used.
A key promise of process languages based on open
standards, such as the
Web Services Business Process Execution Language, is the avoidance of vendor lock-in through the portability of process definitions among runtime environments. Despite the fact that today, various runtimes claim to support
this language, every runtime implements a different subset,
thus hampering portability and locking in their users. In this paper, we intend to improve this situation by enabling the measurement of the degree of portability of process definitions. This helps developers to assess their process definitions and to decide if it is feasible to invest in the effort of porting a process definition to another runtime. We define several software quality metrics that quantify the degree of portability a process definition provides from different viewpoints. We validate these metrics theoretically with two validation frameworks and
empirically with a large set of process definitions coming from several process libraries.
More than five years have passed since the final release of the long-desired OASIS standard of a process language for Web Services orchestration, the Web Services Business Process Execution Language (BPEL). The aim of this standard was to establish a universally accepted Web Services orchestration language that forms a core part of service-oriented architectures and, because of standardization,
avoids vendor lock-in. By now, several fully conformant engines should have arrived in the market. It is our aim to shed light on this situation and to provide a comprehensive picture of the
current state of BPEL upport. We present an evaluation of the standard conformance of five open source BPEL engines.
To obtain these results we have developed betsy, a tool that allows for a fully-automatic standard conformance testing of BPEL engines. The results demonstrate that full standard
conformance in contemporary engines is still far from given.
Although BPMN 2.0 is an international standard widely used in practice, interoperability of process models is still an issue. Even between tools and engines claiming to be BPMN compliant the model exchange is often complicated or impossible as the tools produce incorrect model representations or do not support the standardized BPMN serialization format. In this position paper we present reasons for interoperability issues and show why defining a set of constraints derived from the standard is crucial to fix an important subset of those issues. We are currently developing a tool which can check this set of rules automatically.
Service orchestrations are a powerful tool for
implementing intra– and interorganizational business processes
that base on services. Several heterogeneous orchestration
languages can be found in contemporary IT landscapes. While
the Web Services Business Process Execution Language (BPEL)
is the de facto standard, others gain attention, including Windows
Workflow (WF) in the .NET segment. When integrating
orchestrations, incompatibilities between them can easily arise.
In this paper, we investigate an automated Petri net–based
integration between BPEL and WF to solve these issues with
behavioral adapter services. We provide a mapping of WF to
Open Workflow Nets (oWFNs) and implement it in a compiler.
Thereby, we integrate our approach with existing approaches
for BPEL and adapter synthesis and validate the integration
with a standards–based case study using the two languages.
Various approaches for service-oriented business-to-business integration (B2Bi) rely on a top-down development methodology. The starting point is a choreography model which is subsequently partitioned into multiple orchestrations. Most current approaches use the Web Services Business Process Execution Language (BPEL) for implementing the latter. At the same time, a plethora of other languages, such as Business Process Model and Notation (BPMN) 2.0 process diagrams, is available. As integration partners are free to select the orchestration language of their choice, it should be easy to integrate different orchestration languages with current choreography technology. Language transformation, starting from a suitable format, is a means to achieve this. In this paper, we assess BPEL 2.0 and BPMN 2.0 process diagrams for their suitability for this transformation in a services-based B2Bi setting using a requirements framework identified through a literature study.