Internet環境程式碼再利用之研究

Abstract

近年來，軟體再利用技術已被認為是有效提升軟體產能與品質的方法。軟 體再利用意指在軟體發展過程中，軟體發展者利用現存的軟體產物（ Software Artifacts），加以組合發展新的軟體系統，發展者透過搜尋引 擎（Search Engine）至元件庫（Reusable Component Repository）中尋 找合用的軟體元件並了解（Understand）其功能行為，進而篩選出最合適 的軟體元件予以決定直接使用或修改（Adapt）利用。軟體產物的種類包 含：需求規格、軟體架構、程式碼等，從軟體發展過程各階段中所產生的 角度來看，軟體再利用的層次主要可以分為：程式碼再利用，設計再利用 以及需傳統的程式碼再利用面臨了(1)軟體元件庫中的元件數量、種類及 涵蓋的領域範圍皆有限，以及(2)受限於語言及執行平台的不同，程式碼 元件的修改成本甚高等兩個問題，使程式碼再利用之效益大打折扣。為了 解決上述的問題，本論文結合近年來盛行之Internet/WWW/Java技術，設 計一Internet程式碼再利用環境，利用Internet/WWW上之Broker為媒介， 收集各Vendor所提供的元件，大幅提升程式碼元件的數量與種類，而以 Java程式碼元件為再利用對象，藉由其跨平台的特性，亦大幅降低由平台 不同所帶來的修改成本。欲提供使用者一良好的Internet程式碼再利用環 境，Broker必須滿足底下之服務需求：對使用者而言(1)標準化之元件搜 尋檢視機制，(2)元件搜尋快速且按需求滿足程度依序列出，(3)元件之品 質良好；對元件提供者而言必須能提供一健全交易機制；對Broker之 Administrator而言，希望(1) Vendor應提供元件完整封裝資訊，(2) Vendor應提供元件之測試資料以供執行品質保證工作。欲滿足上述的需求 ，Broker必須提供Classification，Packaging，Component Catalog Repository，Search Engine，Understanding，Registration， Qualification，Trading，Maintain等機制，本論文將就Classification ，Packaging，Component Catalog Repository，Search Engine， Understanding與Registration等機制提出解決方案。並在Internet上製 作提供這些機制之Broker。 Software reuse has been considered to be an effective methodology to improve software productivity and quality recently. Software reuse means developer can assemble various existed software artifacts into a new software system. Software artifacts include requirement specification, software architecture, source code, etc. According to the software artifacts, software reuse can be divided into three level: code reuse, design reuse and requirement specification reuse.Several problems are existed in traditional code reuse: (1)The amount and scope of component contained in repository are quite limited, (2)Due to language and platform difference, the cost of source code modification is high. Those two problems make the benefit of code reuse quite limited.To solve those two problems, this thesis designs an Internet code reuse environment by using the famous Internet/WWW/Java technology. The environment uses a Broker as component media. It collects various component from different Vendors (Component provider) connected to Internet. Thus, the amount and scope of component can become very much, and due to the platform independent feature of Java code, the cost of source code modification could be lowered.In order to provide user a good Internet code reuse environment, broker has to provide the following mechanisms: for user (1)Standardized component search and inspection, (2)Fast component search and list candidate components by their similarity for user to evaluate, (3)Good component quality; for vendor, broker has to provide a secure trading mechanism; to broker administrator, Vendor should provide component information and test case that required for quality assurance.To sum up, broker has to provide Classification, Packaging, Component Catalog Repository, Search Engine, Understanding, Registration, Qualification, Trading, and Maintain mechanism. The thesis will focus on Classification, Packaging, Component Catalog Repository, Search Engine, Understanding, Registration mechanism, and implement them as a broker system on the Internet.