Michael Gebhart

A Model-Driven Approach for Monitoring Business Performance in Web Service Compositions

Supporting business services through Web service compositions (WSC) as part of service-oriented architectures (SOA) involves business performance monitoring requirements. Their implementation results in additional development activities. To support these activities, we already contributed a model-driven approach to the development of monitored WSC as part of our preliminary work. In this paper, we present an extension to this approach, which focuses on supporting the specification and transformation of indicators to an executable implementation. To reduce development effort for this particular task, we provide a template-based mechanism for defining performance indicators. In combination with our preliminary work, now fully monitored WSC can be generated automatically from platform-independent design models. We demonstrate the applicability of the overall approach by instantiating an integrated development process for a target platform based on IBM SOA products and showing its application for a sample business process along with monitoring requirements.

Evaluation of Service Designs Based on SoaML

In the context of service-oriented architectures, services are expected to fulfill certain service characteristics, such as high autonomy or loose coupling. In order to easily influence the design of these services, it is desirable to evaluate their characteristics early on in the development process, i.e. during design time. Related work focuses on the description of desired service characteristics that refer to services as a whole and does not address the evaluation of service designs in terms of their characteristics. Thus, in this paper, we analyze common and widespread service characteristics, derive evaluable design attributes that refer to elements of service designs based on SoaML, and demonstrate the formalization of an exemplarily design attribute using OCL. The application of the identified design attributes on a tentative service design of a service-oriented surveillance system helps to create a revised service design with improved service characteristics.

Supporting Service Design Decisions

In the context of service-oriented architectures, services are expected to fulfill certain service characteristics, such as loose coupling or high autonomy. When designing new services, several decisions have to be made, such as how to group capabilities into services, that influence these characteristics. Existing development processes focus on the description of necessary steps to create services and do not explicitly describe detailed design decisions and their impact on the service characteristics. In this paper, an approach is introduced to determine this impact in order to support the design decisions. The approach is applied to design services of a service-oriented surveillance system with comprehensible service characteristics.

Rule-Based Service Modeling

In the context of service-oriented computing, services provide the capabilities necessary to support the business, especially its processes. Within the service modeling process, the services that constitute a common and stable basis for all supported processes have to be identified. The consideration of each business process on its own, without guidelines, may yield a service inventory that is not adjusted with all requirements, and for instance contains several services providing the same capability, having an inappropriate granularity, or using different taxonomies. Thus, this paper suggests applying rules on a model capturing relevant business requirements to systematically derive a blueprint as a proposal of necessary services. The approach is exemplified by a scenario at the Karlsruhe Institute of Technology (KIT), where it is applied in the context of module catalog management.

Flexible and Maintainable Service-Oriented Architectures with Resource-Oriented Web Services

The implementation of service-oriented architectures is mostly driven by the motivation to create a flexible and maintainable IT. Whether this goal can be achieved or not strongly depends on the design quality of the services. For that reason, the services within a service-oriented architecture have to be created with care. In the past, several quality attributes and quality indicators were identified that provide information about the design quality of a service. These quality indicators were described with focus on method-driven services based on SOAP. However, today, services are often designed in a resource-oriented way using REST or similar approaches to enable technology-independent interactions. For that reason, this chapter maps the existing quality attributes and quality indicators onto resource-oriented web services. As result, architects and developers get a toolset to design resource-oriented web services in a service-oriented architecture systematically in a quality-oriented manner. The quality indicators are illustrated by means of a resource-oriented web service in the context of a service-oriented SmartCampus system developed at the Karlsruhe Institute of Technology. The scenario shows that the application of the quality indicators limits the design scope and accelerates making design decisions.