FJM2 - 分散式Java 訊息服務系統

Abstract

隨著網際網路的日益發達，程式之間彼此透過網路來溝通及交換訊息的需求 也漸趨頻繁。而像Java 訊息服務系統(JMS)這類以訊息導向之中介層程式不但可 以讓網路程式開發的技術門檻大幅降低，同時還有快速發展具可靠性、安全性， 事件驅動等特性。傳統的用戶端/伺服器模式需要用戶端程式自行管理及維護建 立連線的系統資源；同時伺服器端也必須將相同的資料複製到與使用者數量相等 的份數來傳遞，不但浪費系統資源也浪費了網路資源。 本論文研製之Fast Java Messaging 2 (FJM2) 系統為91 年度洪傳寶學長所設 計Fast Java Messaging (FJM)系統的改良版本。FJM2 建構了一種嶄新的JMS 系 統，具備了分散、高速、可靠而且比其他JMS 產品更容易配置與使用！FJM 2 因為使用了更有效率的Negative-acknowledgment (NACK)-Oriented Reliable Multicast (NORM) 通訊協定，而不再採用Topic Address Binding 的技術，所以 FJM2 的Publisher 與Subscriber 可執行在同一台電腦，這是FJM 無法做到的模 式；另外FJM2 還提供了穿越Internet 溝通的能力，大幅擴大了系統的覆蓋範 圍，相對地也為擴展了可能的應用範圍。本研究的經驗，可供想利用 Java 和 Multicast 通訊協定來開發網路通訊中介軟體的讀者作為參考。

With the growth of internet, the requirement for the communication and message exchanges between programs becomes more and more popular. And the Message- Oriented Middleware (MOM), such as Java Message Service (JMS), could not only greatly reduce the technical doorsill for programmers but also has some amazing characteristics: such as reliable, secured, and event-driven. In the traditional Client / Server model, not only the client side program has to maintain the resource for connections and memory management, but also the server side has to send out several copies of duplicated messages per amount of connected clients, it not only waste the system resource but also the network environment. A system this thesis develops is Fast Java Messaging 2 (FJM2), it’s a resigned of Fast Java Messaging (FJM) which designed by Chuan-Pao Hung at 2002. FJM2 creates a whole new JMS provider which is distributed, high performance, reliable, and easy to use and deploy! While compared with FJM, FJM2 adapts a more efficient communication protocol - Negative-acknowledgment (NACK)-Oriented Reliable Multicast (NORM), and no longer adapts Topic Addressing, and thus FJM2 could have Publisher and Subscriber running at the same machine, while FJM could not, and moreover FJM2 has the ability to work across WAN environment, and thus it extends the system coverage, and could be adapted for more different application scopes. We hope that our experience would benefit those who want to create a MOM system based on Java and multicast protocol.