從元件規格到實際元件實施之對映研究：一個基於非同步訊息呼叫的方法

Research for Mappings from Component Specifications to Component implementations：An Approach Based on Asynchronous Message Call

林至中(Jyh-Jong Lin) ； 陳建霖(Chien-Lin Chen)

《資管評論》 14期 (2006/03) Pp. 113-141

https://doi.org/10.6131/MISRb.200603_(14).0006

摘要

元件式軟體工程（Component-based Software Engineering）已逐漸取代傳統的軟體工程，成為發展企業軟體的新一代軟體工程典範。它有著組合（composition）及重用（reuse）的特性。而元件式軟體工程必須要有元件塑模方法論在背後支持，才能夠將企業的需求轉換成最終的元件，當使用元件塑模方法論最後產出元件規格後，下一步就是實際將所描述的元件規格用業界各種軟體元件模式標準（例如COM+、EJB、CORBA等）來實作（implementation）。而在這樣的實作上必須要將所描述的元件規格（component specification）圓滿地表現出來，其關鍵就是要有良好且完整的對映（mapping）。此外，由於網際網路的蓬勃發展，在軟體元件架構上也已邁向了分散式物件運算的架構，而在一個成功的分散式運算中，是經常需要非同步訊息（asynchronous message）傳遞的。所以本文主要就是對於從元件規格到實際元件實施的對映上，加入非同步訊息傳遞的考量，進而提出一個新的對映模式。並且於文章的後段會使用一個線上數位學習課程訂購系統來作為展示此對映研究構思的例子。至於在元件塑模的方法論上，本文選擇較優良的UML Components作為對映研究的方法論，但由於UML Components方法論仍然存在些許缺陷，所以在考量不影響元件於原UML Components方法論的系統架構（system architectures）之分層模式下，本文實際上採用的是經過擴充改善的版本。在實際元件實施上，則是採用Sun公司的EJB（Enterprise Jva Beans）軟體元件模式標準，主要是因為EJB是J2EE（Java2 Enterprise Edition）的核心，而J2EE支援了較為廣泛應用於現有企業系統的分散式運算服務（例如RMI/IIOP、XML-RPC、CORBA、SOAP等等）。透過此新對映模式，當業界在元件軟體發展上是使用UML coponents及EJB，且有非同步訊息傳遞考量之需求時，就能夠良好且快速的完成實際實作（implementation）。

關鍵字

元件式軟體工程 ； 對映 ； 非同步訊息 ； EJB

並列摘要

Component-based Software Engineering has gradually replaced the traditional software engineering. With the trait of composition and reuse, it has become the paradigm of new software engineering techniques for developing enterprise software. Component-based Software Engineering demands the support of a component modeling methodology that enables transferring the enterprise requirements into the final component. After using a component modeling methodology to produce component specification, the specification can be practically implemented in a variety of standards of software component model (e.g., COM+、EJB、CORBA) in the enterprise. In order to successfully implement the specification, excellent and complete mapping is a key factor. Furthermore, due to the thriving development of Internet, the architecture of software component has matched that of distributed object operation. Since a successful distributed operation frequently requires the transfer of asynchronous message, this study mainly focuses on mappings from component specifications to component implementations that augment the consideration about the transfer of asynchronous message to come up with a new model of mapping. To illustrate, an on-line e-Learning curriculum order system will be used for demonstrating the mapping idea. For completing the component modeling methodology, this paper adopts an amended edition of the original UML Components methodology. In the context of the practical implementation of component, this paper adopts EJB (Enterprise Java Beans) software component model standard. The reason is because EJB is the core of J2EE (Java 2 Enterprise Edition), and J2EE supports the distributed operation services (e.g., RMI/IIOP、XML-RPC、CORBA、SOAP) that are widely applied by many enterprise systems. With this new mapping model, when enterprises use UML Components and EJB on component software development, and any systems have requirements of transferring asynchronous message, the implementation can be more effective.

並列關鍵字

Component-based Software Engineering ； mapping, asynchronous message ； UML Components ； EJB(Enterprise Java Beans)

參考文獻

Sterling Software Component-Based Development Method (available with COOL: Spex and COOL: Gen products)

Sterling Software Component-Based Development Method (available with COOL: Spex and COOL: Gen products)

Microsoft Corporation

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Chessman, J.,Daniels, J.(2001).UML Components.Boston:Addison-Wesley.