中文摘要：

软件构件库是支持基于构件的软件开发的基础设施．在软件构件库中，构件的分类描述是复用者检索和理解构件的基础．随着构件技术的发展，构件库程不同领域的得到了应用，构件分类描述机制也面临着扩展性和变化性的挑战．提出了支持多领域构件描述的分类描述模型ECDM，并基于该模型，实现了青鸟构件库管理系统中多种分类模式的定制以及对构件描述属性扩展的支持。

英文摘要：

Reusable software component repository is one of the foundation establishments in component based software development （CBSD）. In component repository, component＇ s classification information and attribute information help the retriever to search and reuse the described components. As component technology advances, new description mechanisms are called for so as to fulfill different needs in various application fields. In this paper, we propose an extendable classification description model （ECDM） that can be applied to component repository manage systems in different domain or company. In detail, the description mechanisms based on the ECDM is divided into two parts： classification extend mechanism and attribyre extend mechanism. The classification extend mechanism provides custom-built component classification description in taxonomy of attribute-value, enumerated, faeeted, and keyword. A publisher can define, maintain and update his classification description models, but deletion is permitted only if no component refers to them. On the other hand, the attribute extend mechanism supports accommodating component attributes description with attribute-value taxonomy. In application, we consider both attribute-value limited and attribute-value unlimited described attributes, which is known that the type and value-scope of described attribute is user-defined in attribute-value unlimited scenario. The ECDM has already been used in the Jade Bird Component Repository Manage System developed by Peking University, where Component Manager can define various component classification models so that a user can describe his component with proper classification information and necessary attribute description information.