並行軟體功能分解式物件導向分析方法

Abstract

近年來，由於平行計算與分散式計算等軟體並行性處理機制之發展，軟體系統的運作方式走向並行性與分散性，一般稱能夠同時執行多個程式單元之軟體系統為並行軟體。以往之物件導向分析設計方法，大多著重於循序軟體的分析設計，對於軟體並行性的支援往往不足。因此，本研究主旨在於提出一套適用於並行軟體之分析方法。 先前之「並行軟體功能分解事物件導向分析方法」有幾項缺點：1) 對周邊環境定義不足；2) 並行性質探討不足；3) 分析步驟無法逐步改良設計；以及4) 動態模型之不足。本論文將針對這些缺點提出分析方法之改良，將並行性質區分為使用者層次並行性、問題領域並行性以及設計層次並行性三個層次，分階段於分析步驟中解決。改良過後之「並行軟體功能分解事物件導向分析方法」以系統外在環境與需求之定義為出發點，提出一套螺旋狀分析方法，將分析過程分成1) 單一使用者模式；2) 單一系統功能；與3) 多使用者模式以及系統功能平行執行模式三個進程。此螺旋狀分析提供分析師逐步解決對應之並行性問題並改良分析成果。 「並行軟體功能分解事物件導向分析方法」產生之分析模型包括：角色模型、劇本流程圖、類別模型、動態模型與部署模型。角色模型描寫組成系統的角色以及角色之間的合作關係；劇本流程圖完整定義系統功能執行流程，並記錄可能發生的並行性問題與處理策略；類別模型定義系統靜態的組成與類別之間的關係；動態模型以物件之間互動描寫系統動態行為，並協助驗證系統功能；部署模型定義軟體於電腦系統中的實際部署與配置。上述五大分析模型以各角度切入系統，對分析結果提供完整之定義。 本方法已成功應用於「銀行資訊系統」之需求分析上，足以驗證本方法之可行性以及分析模型的完整。

Recently, the emerging parallel and distributed computing techniques move the software systems from sequential software to concurrent one. In general, concurrent software is the one with multiple execution units that are executed concurrently. However, conventional analysis and design methods are dedicated to the development of sequential software, but do not support the concurrency in software. The goal of the thesis is to propose a requirement analysis method for concurrent software. The former research of "Functional Decomposition Object-Oriented Analysis for Concurrent Software" has several deficiencies: 1) the definition of execution environment, 2) the weak of concurrent behavior representation, 3) the non-progressive refine process, 4) and the lack of dynamic model. In this thesis, we will propose an improved method to alleviate these deficiencies in the following aspects: The concurrent behavior is classified into three levels: user level, problem domain and design level concurrency. These issues are solved in different stages in the analysis step. The enhanced "Functional Decomposition Object-Oriented Analysis for Concurrent Software" starts from the definition of environment and requirements. We separate the analysis steps into three phases within a spiral: 1) single user mode, 2) multiple user in single function execution mode, and 3) concurrently execution of multiple functions mode. The spiral analysis provides an incremental process to solve the relevant concurrent issues, and embody the result into that of a previous phase. The deliverables of "Functional Decomposition Object-Oriented Analysis Method for Concurrent Software" are role model, scenario diagram, class model, dynamic model and deployment model. Role model is used to express the roles that compose the system and collaboration among them. Scenario diagram defines the execution flows of system functions. It also keeps track of the concurrent issues and the corresponding control policy that may occur in the execution flow. Class model defines the static compositions of classes in the system. We also use notations to represent the relationships between these classes. Dynamic model uses the interactions among objects to prescribe dynamic behavior of the system. The dynamic behaviors of objects help verify the system functions. Finally, deployment model defines the physical deployment of software in a distributed system. The above five model can delineate the system in five views, and provide the necessary and complete result of the analysis. We have successfully applied our research to the requirement analysis of "Bank Information System", and thereby verify the feasibility of our analysis steps and the completeness of the analysis models.