http://dl.gi.de/handle/20.500.12116/25134 2026-07-22T20:35:06Z http://dl.gi.de/handle/20.500.12116/24106 Explicit high-level rules for the customization of web services management Cibrán, María Agustina; D'Hondt, Maja Hirschfeld, Robert; Polze, Andreas; Kowalczyk, Ryszard Current Web Services integration approaches fail at supporting a highly flexible service selection and management. To overcome these problems, the Web Services Management Layer was proposed in previous work. However, this layer presents some limitations due to the implicit representation of service criteria that guide its customization. In this paper we propose externalizing these criteria as highlevel business rules. Moreover, the specification of new unanticipated business rules is also supported. We do this by employing a high-level business rule language proposed in previous work. We show how this rule language can be used to customize the WSML, enhancing flexibility. The originality of our approach is the application of a general-purpose business rule language to the domain of Web Services management. 2006-01-01T00:00:00Z http://dl.gi.de/handle/20.500.12116/24105 The role of reflective middleware in supporting flexible security policies Xu, Na; Blair, Gordon S.; Myrvang, Per Harald; Stabell-Kulø, Tage; Grace, Paul Hirschfeld, Robert; Polze, Andreas; Kowalczyk, Ryszard Next generation middleware must support applications in the face of increasing diversity in interaction paradigms, end system types and network styles. Therefore, to secure applications, security policies must be configured and indeed reconfigured at runtime. In this paper, we propose an approach combining the openness of reflective middleware with the flexibility of programmable security to meet such demands. In particular, we build a security architecture based on the Gridkit reflective middleware platform and the Obol security protocol programming language. The paper then describes a case study that uses flexible policies in order to secure remote procedure calls and secure group communication. We also present the benefits of this approach in terms of flexibility, ease of use and extensibility. 2006-01-01T00:00:00Z http://dl.gi.de/handle/20.500.12116/24107 GDT: A toolkit for grid service development Friese, Thomas; Smith, Matthew; Freisleben, Bernd Hirschfeld, Robert; Polze, Andreas; Kowalczyk, Ryszard The inherent complexity of Grid application development is an obstacle to the widespread adoption of service oriented Grid technology. In this paper, a software development environment for service oriented Grid applications integrated into the Eclipse platform is presented. Its design is based on model-driven software development principles, allowing domain experts to rapidly develop Grid applications by hiding the complexities of Grid middleware. The functionality of the three main components supporting service creation, process creation and interactive debugging are presented, and implementation issues is discussed. 2006-01-01T00:00:00Z http://dl.gi.de/handle/20.500.12116/24102 Avoiding infinite recursion with stratified aspects Bodden, Eric; Forster, Florian; Steimann, Friedrich Hirschfeld, Robert; Polze, Andreas; Kowalczyk, Ryszard Infinite recursion is a known problem of aspect-oriented programming with AspectJ: if no special precautions are taken, aspects advising aspects can easily and unintentionally advise themselves. We present a compiler for an extension of the AspectJ programming language that avoids self reference by associating aspects with levels, and by automatically restricting the scope of pointcuts used by an aspect to join points of lower levels. We report on a case study using our language extension, and provide numbers of the changes necessary for migrating existing applications to it. Our results suggest that we can make programming with AspectJ simpler and safer, without restricting its expressive power unduly. 2006-01-01T00:00:00Z