軟體再利用的元件搜尋與組裝之研究

Abstract

軟體再利用是一個能有效改善軟體生產力與品質的方法，一般軟體再利 用的程序可依序分為四個階段：「抽象化」(abstraction)、「選擇」( selection) 、「特殊化」(specialization)及「組裝」(integration) 。本論文的研究內容包含二個部份，一是幫助找尋程式碼，另一個是幫助 組裝程式碼，分別用以改善「選擇」與「組裝」二個階段以便能有效再利 用。在找尋程式碼部份，目前大部份的程式庫並沒有提供良好的機制來協 助不同程度的使用者進行搜尋的動作。而在組裝程式碼部份，目前Web資 料庫軟體的程式模組大都是透過檔案來區分，導致軟體的程式邏輯是分散 在檔案上。當程式設計師在組裝過程修改了某部份的程式時，所有受到此 修改而影響到的檔案都需要一併修改以維持功能的一致性，而如何準確地 確認出這些受到影響的程式將直接影響到Web資料庫軟體在程式組裝上的 效率。 在本論文中提出一個「軟體再利用架構」(SRF)來克服找尋程式 碼的缺點，SRF以一個內建的階層化同義辭典為基礎，使得分類流程可以 以半自動化的方式來進行；SRF也是一個領域獨立的系統架構，可以適用 到不同的程式庫來提供分類與搜尋的動作。SRF提供四個搜尋等級來服務 不同程度的使用者。在組裝程式碼方面，針對上述Web資料庫軟體在程式 組裝上的需求，本論文中提出了一個HED模型，此模型利用三種圖形-超鏈 結圖、實體關係圖及資料流程圖-來表示一個軟體的程式邏輯。藉由將軟 體的程式邏輯明確地描述在HED模型後，受到某個修改所影響的程式將可 以透過結構性分析與資料庫分析而被準確的確認出來。 此外，二個SRF 的範例系統也被實作出來，一個針對Smalltalk-80的程式庫，另一個是針 對MFC 4.0的程式庫。論文中將提供統計資料來說明這二個程式庫在分類 動作中透過SRF架構所降低的人力負擔。並且藉由一個實驗來實際驗證SRF 架構在搜尋上的效率，並且結果顯示SRF使得搜尋速度加快了百分之33.2 。另一方面，一個以HED模型為基礎之分析工具也被實作出來，在本論文 中將實際展示此分析工具的各項操作功能。 Software reuse is an effective way to improve software productivity and quality. The process of software reuse can be divided into four phases: abstraction, selection, specialization, and integration. In this thesis, the research includestwo parts: one is component retrieval and the other is component integration. Theyare aimed to improve the effectiveness in the selection and integration phases, respectively. For component retrieval, current software libraries provide all userswith the same search/display order. The retrieved/display results are not suitablefor users for their abilities well. For component integration, current web databaseapplication programs may consist of hundreds of files and the application logic is distributed on the files. When a programmer modifies some program files of an application on the integration phase, the program affected should be updated simultaneously to keep the functional consistency. The identification of the affected programs directly influences the effectiveness of program integration. In this thesis, a Software Reuse Framework (SRF) is presented to improve componentretrieval based on a (built-in) hierarchical thesaurus. The classification process ofa code library was made in a semi- automatic way. SRF is a domain-independent frameworkthat can be adapted to various libraries. SRF also provides four search levels to provide users of different skill levels with correspondent search/display order. Forthe component integration, a model called HED model is presented to meet the prior requirement of web database applications. HED model is composed of three diagrams, hyperlink diagrams, entity- relationship diagrams, and data-flow diagram, to representthe logic of application programs. Based on the HED model, the programs files affectedby a program modification can be identified precisely via the structure and database analyses. In addition, two sample SRF systems* are implemented, one for Smalltalk-80 and the other for MFC 4.0 (MicrosoftR Foundation Class) libraries. Some information collected during classifying these two libraries shows that the classification effort is reducedvia SRF. Another experiment is designed to evaluate the feasibility of SRF search process. The result reveals that the SRF search process achieve 33.2% speedup on the average. On the other hand, an analysis tool is implemented based on the HED model. The functionalities of this tool are presented in detail.