由結構化分析結果產生快速軟體雛型之研究

Abstract

It is commonly believed that rapid prototyping can be an important software development approach to tackling recent software crisis, which advocates that a working prototype of the intended system should be quickly produced at the requirement analysis stage for both the system analysts and the users to clarify their expectations. It is evidently necessary that the rapid prototyping method should be reconciled with the customary system analysis paradigms. However, few existing approaches have put emphasis on this reconciliation. In this dissertation, we propose a new approach to rapid prototyping based on the intermediate result of popular system analysis method, the DeMarco's Structrued Analysis (SA). The key problems of directly translating the data flows and mini-specifications of SA method are addressed. Then a new prototyping approach for tackling these problems is proposed. This approach includes a conceptual model, a specification language, and a prototyping enivironment. A two-level model is used to conceptualize the functionality of a prototype from the analysis result of SA. In this model, a prototype is constructed with a set of transactions and a set of objects. The former represents the operation logic of the system service hierarchically grouped into levels of menus. Based on the two-level model, a prototype specification language is proposed. To provide an adequate way for conveniently writing of prototype specifications from the SA results and easy enhancement of prototype functions, the specification of a prototype consists of two parts. Transactions are described in a procedure form, but objects are defined by states and state transition tables. To exhibit the behavior of prototypes, a prototyping environment is also developed in this deiieration. A prototype of a library system practiced on this environment shows the feasibility of the proposed approach. The primary originality of this research is that we advocate the process of rapid prototyping should be reconciled with the process of system analyisis. In this dissertation, an approach to rapid prototyping from the result of SA approves the advocacy. In addition, we have proposed an appropriate way to describe the prototypes without need of programming the primitive stubs or writing mathematical formulas, which are commonly imposed on the previous approaches. These merits would promote the effectiveness and efficiency of software rapid prototyping. I would like to express my sincere gratitude to Professor Chyan-Goei Chung, Professof Feng-Jian Wang, Professor Deng-Jyi Chen, Professor Jenn-Yan Chen, and Professor Ching-Roung Chou for their time and effort as members of my dissertation advisory committee. Special gratitude goes to my advisor, Professor Chyan-Goei Chung for his invaluable guidance and inspiration. Thanks are presented to all the members of SIEL (Software and Information Engineering Laboratory) for their useful discussions and suggestions. I would also like to thank the National Science Council,R.O.C. for partial financial support of this research. I gratefully acknowledge all the members of my family and my friends for their constant love and encouragement throughout my graduate school education. I affectionately dedicate this dissertation to all of them . 快速軟體雛型（ Software Rapid Prototyping）之目的是使系統分析階段可快速產 生一個可執行模式（即軟體雛型），使用戶實地演練，以確認需求規格之正確性．因 此軟體雛型之模式須密切配合系統分析之方式，方易有效達到確認需求規格之目的． 然而，目前的方法仍多有不易與傳統的系統分析方式結合的缺點． 本研究之目標乃是針對目前最廣為使用的”結構化分析”（Structured Analysis， 簡稱SA）方法，提出一個可與之搭配的快速軟體雛型產生方法．本文首先探討直接由 SA的結果產生軟體雛型所面臨的主要問題；進而提出一套新的雛型產生方法以解決這 些問題．此方法包含一個兩層式的雛型構建模式（Prototype Construction Model） ，一個與之對應的雛型規格描述語言（Prototype Specification Language），以及 一個雛型操作環境（Prototyping Environment）． 兩層式的雛型構建模式將一個雛型系統模塑成一個階層式的架構；上面是由一組組的 ”TRANSACTION”建立起來的，每個TRANSACTION代表一個系統所提供的功能．而在這 些TRANSACTION之下的是一個個的”OBJECT”，每個OBJECT 代表一個系統在操作過程 中必須用到的資料體（data entity）及允許作用於此資料體之基本動作（primitive operation）． 為了易於描述雛型之功能規格，在雛型規格語言中，本研究採用程序敘述的方式來描 述每個TRANSACTION 的運作邏輯（operation logic ）；而各個OBJECT則用表列的方 式來描述其基本動作所可能產生的狀態變化及可能的得出的運算結果．此方式的好處 是規格容易寫，容易修改；且用填表的方式可以不勿要求完整的功能描述，很適用於 軟體雛型之功能不完整性（functional incompleteness）． 本研究並已設計及製作出一個雛型操作環境．在此操作環境上面可以執行雛型規格以 展現系統功能，而達到及早確認需求規格之目地．在本論文中我們以一個小型的圖書 管理系統為例，詳細的說明了雛型系統規格之構建及其操作之原理．