This development environment enables the specification , automated composition , and quality analysis of flexible , configurable middleware architectures , notably in distributed systems . Systematic Aid for Developing Middleware Architectures

Middleware is necessary for developing distributed systems. Developers compose them from reusable services provided by standard or proprietary middleware infrastructures, including the Object Management Group’s Common Object Request Broker (CORBA), Microsoft’s Distributed Component Object Model, Sun Microsystems’ Java Remote Method Invocation, and related services, to deal with nonfunctional requirements for distribution, security, transactional processing, and fault tolerance. The development process has been made easier by following the object-oriented middleware paradigm toward the componentbased middleware paradigm, which includes the CORBA Component Model, the Microsoft Transaction Server, and Enterprise JavaBeans. Developers can ignore the sometimes considerably complex composition of middleware services. Instead, they build middleware components, deploying them in off-the-shelf middleware containers in order to customize the composition of middleware services. Containers range from base ones with standard and proprietary middleware infrastructures, to more complex ones from commercial vendors extending the semantics of the base containers. Base containers typically provide transparent persistent storage and transactional and secure access to components; complex containers further combine other proprietary services. However, assembling off-the-shelf components into containers is less straightforward then it might appear. To be able to offer middleware containers, vendors have to design and implement architectures combining available middleware services into flexible and customizable structures. Middleware services are not monolithic; they consist of a number of elements that, used appropriately, provide certain nonfunctional properties. Combining more than one middleware service amounts to composing the elements of each service. In general, various methods are used to compose these elements to satisfy application nonfunctional requirements. The resulting compositions should be supported by the configurable middleware architecture provided by middleware container vendors, especially to programmers. Moreover, off-the-shelf middleware architectures should come with a quality assessment of the possible compositions they support. This assessment should give developers clues for selecting the most suitable compositions for their particular applications. Addressing these issues, we have developed an environment that facilitates the design and quality analysis of flexible and configurable middleware This development environment enables the specification, automated composition, and quality analysis of flexible, configurable middleware architectures, notably in distributed systems. Systematic Aid for Developing Middleware Architectures Valérie Issarny, Christos Kloukinas, and Apostolos Zarras