BuOA: An Achitecture Style for Modular Web Applications

Though Web development technologies have made a dramatic progress in past decades, Web applications are still with a monolithic architecture in terms of their deployment and mechanisms for resolving component interdependencies, imposing constraints on, e.g., partial and dynamic upgrade, distributed and parallel development. In this paper, we propose BuOA (Business unit Oriented Architecture), a novel architecture style for modular Web applications. Compared with traditional layered architecture styles, BuOA vertically decomposes Web applications into a group of BUs (Business Units) each of which implements a complete and cohesive business function. To establish loosely coupled relationship between BUs, interactions between them are categorized into four patterns: observing, injecting, weaving and binding. The paper first explores the BU model based on a three-dimensional view of Web applications, and then presents a connector model that abstracts the four interaction patterns. Practical toolkits and a framework for BuOA-based development are also introduced based on a concrete example. With BuOA, we can design and develop evolvable Web applications in a modular, parallel and collaborative way.