Managing Evolution in Distributed, Heterogeneous Systems

分布式、异构（DH）软件系统对于现代化、全球化组织的运作至关重要。像所有的软件一样，DH系统随着组织需求的发展而受到进化的压力。 调整DH系统以满足安全等领域不断变化的需求是具有挑战性的：在不同语言和不同平台上进行的协调更改必须仍然保持类型安全，并且不得增加复杂性和/或使维护复杂化。本项目研究基于标准的中间件的增强（例如，我们保留并增强了中间件的核心的基于IDL的异构哲学。首先，接口描述语言（IDL），用于建模的组件的体系结构级接口，增强了支持建模的进化变化的DH系统。要创建的新信息的更改位置、类型和生存期都在IDL级别以面向方面的风格显式建模。 代码生成支持广泛的实现选择，以实现这些架构变化模型。所有的实现都是完全互操作的。 最后，变更模型和实现可以“组件化”，打包并添加到现有系统中。像这项研究一样，我们的教育计划也涉及几个主题领域，包括函数式编程、面向对象和体系结构。我们开发了基于实践的软件进化教学法，比较了面向对象、高阶多态性（包括一元编程）、连接器和方面的不同关注点分离方法。

Distributed, heterogeneous (DH) software systems are critical forthe operation of modern, globalized organizations. Like all software, DH systems come under evolutionarypressure as organizational needs evolve. Adapting DH systems to meet changing needs in areas such as security is challenging:Co-ordinated changes, made in different languages, and on differentplatforms must still preserve type-safety, and must not increasecomplexity and/or complicate maintenance. This project investigates enhancements to standards-based middleware (e.g., CORBA) to support evolution.We preserve and enhance the core IDL-based heterogeneous philosophy of middleware. First, interface-description language (IDL),used to model the architecture-level interfaces of components, is enhanced to supportmodeling of the evolutionary changes made to a DH systems. Locationof changes, types and life-times of new information to be created are all explicitly modeled in an aspect-oriented style at the IDL level. Code generation supportsa wide range of implementation choices torealize these architectural change-models. All implementationsare fully inter-operable. Finally, change-modelsand implementations can be "compononentized", packaged up and added to existing systems. Like this research,our educational plans also spanseveral topics areas, including functional programming,object-orientation, and architecture. We develop practically-grounded pedagogy on software evolution,comparing the varying approaches to separation of concerns inobject-orientation, higher-order polymorphism (includingmonadic programming), connectors, and aspects.