物件導向工作流程系統之元件再利用

Abstract

在這篇論文中我們探討工作流程系統(Workflow Management Systems, WfMSs)元件的可再用性(Reusability)。物件導向程式語言的特性允許物件的重覆使用(Reuse)，但由於工作流程系統的運作模式的特殊性，因此單純的使用物件導向程式語言而不考慮工作流程系統的特性，並不一定能實作出可再用的元件。 我們探討工作流程系統中每個元件應該具備的可再用性並指出實作出可再用元件時可能遭遇的困難。為了克服這些困難，我們為工作流程系統提出了一個名為JOO-WfMS物件導向系統模型。在這個系統模型中我們運用設計樣式(Design Pattern) 來提昇元件的可再用性。除了元件架構的設計，在錯誤回復模式(failure recovery model)上，我們採用一套工作流程錯誤處理(workflow failure-handling , WfFH)語言來提供富彈性的錯誤處理模式。在系統與使用者溝通的功能設計上，我們也採用物件配合資料庫的方式來提昇使用者介面的可再用性。在本論文中我們也將提供系統建置的相關經驗報告。In this paper, we focus on the reusability of the components of workflow management systems (WfMSs). Languages that support object-oriented programming now are firmly entrenched in the mainstream. The object-oriented programming language provides support for three key languages features: abstract data types, inheritance, and dynamic binding. As a result, these languages can support the software reuse. According to our study, implementing WfMS in object-oriented programming languages without considering the characteristics of the WfMSs does not always obtain reusable components. We clarify the reusability of WfMSs and point out the difficulties for constructing reusable components for WfMSs. To overcome these difficulties, we propose an object-oriented model for WfMSs named “Java-based Object-Oriented Workflow Management System (JOO-WfMS)”. In JOO-WfMS, we use design patterns for system architecture and components to promote the reusability. Besides, we propose a language, called workflow failure-handling (WfFH) language, to support a flexible failure recovery model in JOO-WfMS. For the design of user communication interfaces, we use user communication components (UCC) to promote the reusability. We also report our experiences in constructing the prototype of JOO-WfMS and experimental results.