Modeling Dynamic Component Interfaces
We adopt a component model based on object-oriented systems, introducing the concepts of components and their structure. A component consists of a dynamically changing set of connected objects. Only some of these objects are interface objects, and are thus accessible from the environment. During the component lifetime not only the number of objects, but also that of interface objects, and their connections change. To describe this situation, we introduce component interface diagrams (CIDs)-an adaption of UML diagrams-as a notation to characterize interfaces of components, their structure, and their navigability. We show how CIDs can be used to describe the in-house developed Open Editor Framework (OEF). Finally, we give guidelines that allow to map components described with CIDs directly to several component technologies, like ActiveX, CORBA, or Java Beans
💡 Research Summary
The paper introduces a component model that explicitly addresses the dynamic nature of modern software systems, where both the internal objects of a component and the set of its exposed interfaces can change at runtime. Traditional component models and UML component diagrams treat components as static entities with fixed interfaces, which limits their applicability to plug‑in based applications, service‑oriented architectures, or any system that must adapt its structure while executing. To overcome this limitation, the authors define a component as a dynamically connected set of objects and distinguish those objects that are visible to the environment as interface objects.
To make this concept concrete, the authors propose the Component Interface Diagram (CID), an extension of UML that adds specific notation for dynamic aspects. A CID consists of a component boundary that encloses all internal objects, explicit symbols for interface objects, navigation arrows that show how a client can reach a particular service, and special stereotypes or annotations that denote creation, destruction, connection, and disconnection events. By combining these elements, a CID can describe not only the static structure of a component but also the possible evolution of its interface set over time.
The paper demonstrates the usefulness of CID through a detailed case study: the Open Editor Framework (OEF), an in‑house text‑editing platform that supports plug‑ins for syntax highlighting, auto‑completion, file format conversion, etc. Each plug‑in is modeled as a dynamically added group of objects; its public API appears as interface objects within the component boundary. The CID for OEF makes the navigation paths between the core editor and each plug‑in explicit, and it visualizes runtime scenarios such as loading a new plug‑in, replacing an existing one, or removing a plug‑in altogether. This visual model helps designers detect interface clashes, understand dependency chains, and verify that required navigation paths are always available.
Beyond modeling, the authors provide concrete mapping guidelines that translate a CID‑specified component into three widely used component technologies:
- ActiveX / COM – Interface objects become COM interfaces; dynamic connections are realized with connection points and event sinks; object lifecycle is managed through IClassFactory and reference counting.
- CORBA – Interface objects are expressed in IDL; the Portable Object Adapter (POA) handles creation and destruction; dynamic linking is achieved via object references passed through CORBA’s naming service.
- JavaBeans – Interface objects correspond to BeanInfo descriptors; property change listeners and custom events implement the dynamic navigation; the BeanContext API can be used to manage runtime addition and removal of beans.
These mappings show that a CID can serve as a technology‑agnostic design artefact, from which concrete implementations can be generated with relatively little manual translation.
The paper’s contributions are threefold: (1) a formal definition of components whose internal structure and exposed interfaces are mutable; (2) a visual notation (CID) that captures both static and dynamic aspects in a single diagram; (3) practical guidelines for transforming CID models into real‑world component frameworks. The authors also discuss limitations: CID requires extensions to existing UML tools, large systems may produce overly complex diagrams, and runtime consistency must be ensured through careful event‑driven programming and factory patterns.
In summary, “Modeling Dynamic Component Interfaces” provides a systematic approach to represent, reason about, and implement components whose interfaces evolve during execution. By bridging the gap between high‑level design and concrete component technologies, the work offers a valuable asset for developers of plug‑in architectures, modular editors, and any software that must adapt its component interfaces on the fly.