Several approaches have been proposed to introduce self-management capabilities for Web service compositions.However, most of these works are limited as they are not extensible, i.e., new self-adaptation features cannot be supported, and even if that is possible then still this cannot be done dynamically while the composite services are running.In addition, many of these works are not based on the service composition standard WS-BPEL. In this paper, we propose a plug-in architecture for self-adaptive Web service composition, in which self-adaptation features are well-modularized in aspect based plug-ins. Our approach supports application-specific adaptation scenarios, is easily extensible, and allows self-adaptation logic to be hot-deployed on running process instances. We have implemented this architecture and several plug-ins using the dynamic aspect-oriented workflow language AO4BPEL.

Dynamic scripting languages such as Ruby provide language features that enable developers to express their intent more rapidly and with fewer expressions. Organizations started using these languages in order to add enhancements to their existing applications or create composite applications. Current research has not yet addressed how security specification and enforcement can be done for scripting based application development. To fill this gap, we developed a framework for the design and facilitation of security. Our approach enables a business oriented application developer to add high-level security intentions to his business process model. The framework supports the automatic generation of security configuration and enforcement. As a proof-of-concept, we present an architecture and report the implementation status.

Current approaches to compiling aspect-oriented programs are in-efficient. This inefficiency has negative effects on the productiv-ity of the development process and is especially prohibitive for dynamic aspect deployment. In this work, we present how well-known virtual machine techniques can be used with only slight modifications to support fast aspect deployment while retaining runtime performance. Our implementation accelerates dynamic as-pect deployment by several orders of magnitude relative to main-stream aspect-oriented environments. We also provide a detailed comparison of alternative implementations of execution environ-ments with support for dynamic aspect deployment.

Language mechanisms deserve language implementation effort. While this maxim has led to sophisticated support for language features specific to object-oriented, functional and logic programming languages, aspect-oriented programming languages are still mostly implemented using postprocessors. The Steamloom virtual machine, based on IBM's Jikes RVM, provides support for aspect-oriented programming at virtual machine level. A bytecode framework called BAT was integrated with the Jikes RVM to replace its bytecode management logic. While preserving the functionality needed by the VM, BAT also allows for querying application code for join point shadows, avoiding redundancy in bytecode representation. Performance measurements show that an AOP-enabled virtual machine like Steamloom does not inflict unnecessary performance penalties on a running application; when it comes to executing AOP-related operations, there even are significant performance gains compared to other approaches.