南京大学：《面向对象技术 OOT》课程教学资源（PPT课件讲稿）分布对象 Distributed Objects（1）

Distributed Obiects 分布对象(1) Institute of Computer Software 2021/2/5 Nanjing University

分布对象(1) Distributed Objects 2021/2/5 Institute of Computer Software Nanjing University 1

最病 过摘要 口背景 a Why What, How 一般框架 口 CORBA 口 Java rm Institute of Computer Software 2021/2/5 Nanjing University

摘要  背景  Why, What, How  一般框架  CORBA  Java RMI 2021/2/5 Institute of Computer Software Nanjing University 4

最病 背景 5 口分布式计算( Distributed computing) a What the process of running a single computational task on more than one distinct computer from Wikipedia Compare to "Parallel computing a Why a Howe 实践表明,分布式应用系统的开发比集中式应用系统开 发困难的多。 Institute of Computer Software 2021/2/5 Nanjing University

背景  分布式计算（Distributed computing）  What: ◼ the process of running a single computational task on more than one distinct computer -- from Wikipedia ◼ Compare to “Parallel Computing”  Why?  How? ◼ 实践表明，分布式应用系统的开发比集中式应用系统开 发困难的多。 2021/2/5 Institute of Computer Software Nanjing University 5

分布式计算 6 Why? 口“世界是分布的”。 有时将涉及的用户、应用、数据集中化不合适、不可行。 口资源共享 并行处理 口冗余容错 → The main goal of a distributed computing system is to connect users and resources in a transparent, open, and scalable way. Ideally this arrangement is drastically more fault tolerant and more powerful than many combinations of stand-alone computer systems Institute of Computer Software 2021/2/5 Nanjing University

分布式计算  Why?  “世界是分布的”。 ◼ 有时将涉及的用户、应用、数据集中化不合适、不可行。  资源共享  并行处理  冗余容错 →The main goal of a distributed computing system is to connect users and resources in a transparent, open, and scalable way. Ideally this arrangement is drastically more fault tolerant and more powerful than many combinations of stand-alone computer systems. 2021/2/5 Institute of Computer Software Nanjing University 6

The Business model Every application is part of your business model must make them work together! Payables/ Receivables Sales Accounting Manufacturing Inventory Shipping/ ReceIving Engineering Distributed Systems Frameworks

Distributed Systems Frameworks 7 The Business Model  Every application is part of your business model  must make them work together! Shipping/ Receiving Inventory Engineering Manufacturing Accounting Payables/ Receivables Sales

The problem e Application Integration and distributed processing are the same thing P Constructing information-sharing distributed systems from di Iverse sources ° heterogeneous networked physically disparate multi-vendor Distributed Systems Frameworks

Distributed Systems Frameworks 8 The Problem  Application Integration and Distributed Processing are the same thing Constructing information-sharing distributed systems from diverse sources: heterogeneous networked physically disparate multi-vendor

常见分布式应用模式 Client- Server Computing Client code Server code Stub Skeleton Infrastructure Client Thin or fat? Distributed Systems Frameworks

Distributed Systems Frameworks 9 常见分布式应用模式 Client Code Stub Server Code Skeleton Infrastructure Client: Thin or Fat? • Client – Server Computing

常见分布式应用模式 ° Multi- Tier systems -- User Interface Persistent Store separates persistence from logic and logic from presentation all activity originates in user interface arrows represent client-server relation Distributed Systems Frameworks

Distributed Systems Frameworks 10 常见分布式应用模式  Multi-Tier Systems  separates persistence from logic and logic from presentation  all activity originates in user interface  arrows represent client-server relation Business Logic User Interface Persistent Store

常见分布式应用模式 ° Web applications Firewall Http Servers Business ogIc CGI/ Servlets Data sto User Interface interaction initiated by user UI based on HTML, Java, Javascript,etc CGI/Servlet composes HTML, forwards interaction requests to business logic Distributed Systems Frameworks

Distributed Systems Frameworks 11 常见分布式应用模式  Web Applications  interaction initiated by user  UI based on HTML, Java, Javascript, etc.  CGI/Servlet composes HTML, forwards interaction requests to business logic Business Logic User Interface Data Store Firewall HTTP Servers CGI / Servlets

常见分布式应用模式 Peer-to-Peer Systems Application Notifications Message Persistent Store queue User Interface (mixed initiative) Monitor Enterprise applications An architecture where there is no special machine or machines that provide a service or manage the network resources Instead all responsibilities are uniformly divided among all machines, known as peers. Peers can serve both as clients and servers. Distributed Systems Frameworks

Distributed Systems Frameworks 12 常见分布式应用模式  Peer-to-Peer Systems Application User Interface (mixed initiative) Persistent Store Monitor Enterprise Applications Message queue • An architecture where there is no special machine or machines that provide a service or manage the network resources. • Instead all responsibilities are uniformly divided among all machines, known as peers. Peers can serve both as clients and servers