Component-based software development is gaining recognition as the key technology for the construction of high-quality, evolvable, large software systems in timely and affordable manners. In this new setting, interoperability is one of the essential issues, since it enables the composition of reusable heterogeneous components developed by different people, at different times, and possibly with different uses in mind. Currently most object and component platforms (such as CORBA, DCOM, or EJB) already provide the basic infrastructure for component interoperability at the lower levels, i.e., they sort out most of the "plumbing" issues. However, interoperability goes far beyond that; it also involves behavioral compatibility, protocol compliance, agreements on the business rules, etc. This chapter tries to go through the basic concepts related to component interoperability, with special emphasis in the syntactic, protocol and operational specifications of components. Our main goal is to point out the existing problems, survey the current solutions and how they address those problems, and to draw attention towards some of the still open issues and challenges in this interesting research area.

. The fact that so many different kinds of coordination models and languages have been proposed suggests that no one single approach will be the best for all coordination problems. Different coordination styles exhibiting different properties may be more suitable for some problems than others. Like other architectural styles, coordination styles can be expressed in terms of components, connectors and composition rules. We propose an approach in which coordination styles are expressed as "component algebras": components of various sorts can be combined using operators that realize their coordination, yielding other sorts of components. We show how several coordination styles can be defined and applied using Piccola, a small language for composing software components. We furthermore show how glue abstractions can be used to bridge coordination styles when more than one style is needed for a single application. 1 Introduction We are rapidly moving towards a world of spontaneo...

Refactoring is a new name for a transformational approach to iterative software development. Originally focused on class diagrams, it is now commonly associated with object-oriented programming languages like Java. In this article, we trace some of the conceptual roots and the ideas behind refactoring, and sketch its relation to other techniques, such as behavioral and structural refinement or compiler optimization. Based on these observations, we firmly believe that improved and adapted refactoring techniques will belong to the methodical tool set of tomorrow's software engineers.

Abstract. Guaranteeing that assembled components will behave as required is one of the main aspects in working with Component-Based Development. In this paper we present a formal approach for tackling this problem by applying the concept of bisimulation, originally presented in the study of concurrency theory. Bisimulation allows us to abstract details that are irrelevant from the behavioral point of view, such as data representations and implementation structures, providing a powerful formalism for proving software correctness properties. Thus, our approach facilitates to demonstrate the behavioral equivalence between the integrated system and the required specification. We introduce these concepts with the help of an example described in RAISE. 1

Lab on Re-Engineering

Component-oriented development of software supports the adaptability and maintainability of large systems, in particular if requirements change over time and parts of a system have to be modified or replaced. The software architecture in such systems can be described by components and their composition. In order to describe larger architectures, the composition concept becomes crucial. We will present a formal framework for component composition for object-based software development. The deployment of modal logics for defining components and component composition will allow us to reason about and prove properties of components and compositions. 1