搜索引擎系统：UML/OCL模型驱动开发

介绍一个搜索引擎系统的开发。运用UML用例图做系统的需求分析，运用UML类图、状态图、包图进行系统设计。以OCL表达式丰富状态图。使用C#语言和ASP.NET编程，SQL Server存储信息，系统运行在微软.NET环境上。遵循面向对象方法，如逐步求精和模块化，建立UML/OCL模型、组织程序，将系统逐层分解成具有特定功能的模块。系统由收集器、索引器、检索器三大部分组成，分别负责数据收集、数据分析和索引构建、用户检索接口。论文报告系统分析、设计和实现的思想和过程。

Search engine:Model-driven development with UML/OCL

A search engine is developed.The use case,class,state and package diagrams of UML are used to do the require- ment analysis and design of the system.The state diagrams are enriched by means of the OCL expressions.This system is programmed in C# and ASP.NET,with SQL Server for storing information,and is run in the Microsoft .NET environment.Fol- lowing the object-oriented methodology, such as refinement and modularization, in building the UML/OCL models and con- structing the program, the system is hierarchically divided into modules of particular functions.The system consists of a col- lector, an indexer and a searcher.They are respectively responsible for information gathering, information analysis and index constructing,and user interface.The paper reports on the ideas and process of the system analysis,design and implementation.