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CORBACORBANTU IMNTU IM蘇威圖張健鴻劉式鈜
ArchitectureArchitecture
NTUIM
CORBACORBAis a specification for
distributed object from the
OMG
( Object Management Group )
Distributed ObjectDistributed ObjectObject distributed over the network
- location not importantObject interact through interface
- invoke an action- obtain the result from the object
Interface hide the object implementation
Why CORBAWhy CORBANetwork TransparencyLanguage IndependencePlatform IndependenceObject interoperabilityOO :
encapsulation 、 polymorphism 、 inheritance
CORBACORBAC ： ComponentO ： ObjectR ： RequestB ： BrokerA ： Architecture
ORBORB(Object Request (Object Request Broker)Broker)Component busLocal/Remote transparencyInvocationObject (program or data object) can be
on the same machine or across network
Self-descriptionHigh level language binding
Interface: Client/Server binding contract
IDL:Interface Definition LanguageImplement object in their own
environment
-various programming language
CORBACORBA
System level System level serviceserviceNaming :map a human-readable
name (string) to an object relative to its context
SecurityPropertyTransaction ： two phase commit for
flat 、 nested transaction………..
Component bus →System level Service →
AP framework →business object
Naming Security Transaction ……………..
ORB
Client Server
C C++ Java Other
IDL IDL IDLIDL IDLIDL IDL IDL
C++C Java Other
CORBA CORBA ArchitectureArchitecture
Client SideClient SideClient IDL Stub (Static Invocation)Dynamic Invocation InterfaceInterface Repository APIORB Interface
Static InvocationStatic Invocation
Client Dynamic Client Dynamic InvocationInvocation
Server SideServer SideServer IDL SkeletonDynamic Skeleton InterfaceObject AdapterImplementation RepositoryORB Interface
Dynamic Serve Dynamic Serve InvocationInvocation
Object AdapterObject Adapter Register Server classes with the
Implementation Repository Instantiate a new object at run time Generate and manage object reference Broadcast the presence of the object server Handle incoming call Route the up-call to the appropriate method=> BOA (Basic Object Adapter)
BOBOAA
What’s nextWhat’s nextAsynchronous method invocationIntegrating Universal Naming Service
- X.500 、 LDAPReal-Time extensions Embedded CORBA
CORBACORBA
CORBA=>
C + ORB + A
CodeCodeAlbert
NTUIM
範例介紹範例介紹利用 OMG IDL 定義 interface
撰寫 Server 端程式
撰寫 Client 端程式
執行程式
IDLIDL MyRemoteInterface.idl
module Example
{
interface MyRemoteInterface
{
string getRemoteIP();
};
};
IDL compilerIDL compiler 利用 compiler ，我們可以產生出 client stub 、 server
skeleton 及 implement client 或 server 端時所需的程式 Sun 在 Java 語言的部分就提供了一個叫 idltojava 的
compiler
idltojava -fno-cpp MyRemoteInterface.idl
http://java.sun.com/products/jdk/1.2/docs/guide/idl/index.html
更多資訊
IDL compilerIDL compiler _ MyRemoteInterfaceImplBase.java
This abstract class is the server skeleton,
providing basic CORBA functionality for the
server.
_MyRemoteInterfaceStub.java
This class is the client stub, providing CORBA
functionality for the client.
IDL compilerIDL compiler MyRemoteInterface.java
This interface contains the Java version of our
IDL interface. It contains the single method
getRemoteIP();
serverserver 端程式端程式Server 端程式主要由下列兩個 Class 組
成
CORBAserver
MyRemoteInterfaceServant
serverserver 端程式端程式 CORBAserver 是用來產生一個 ORB 實體，並且透
過命名（ naming ）的方式註冊成 CORBA 的物件，提供給其他物件使用。
MyRemoteInterfaceServant implement 在MyRemeoteInterface IDL 中所定義的 interface ，所以其必須繼承自 _MyRemoteInterfaceImplBase這個類別
（由 idltojava compiler 產生） 並且 implement getRemoteIP() 這個 method 。
CORBAServer.javaCORBAServer.javaimport Example.*;
import org.omg.CosNaming.*;
import
org.omg.CosNaming.NamingContextPackage.*;
import org.omg.CORBA.*;
import java.net.*;
CORBAServer.javaCORBAServer.javapublic class CORBAServer{ public static void main(String args[]) { try { // 建立並且初始化 ORB 實體 ORB orb = ORB.init(args, null); // 建立 MyRemoteInterfaceServant 並且對 ORB 註冊 MyRemoteInterfaceServant mri = new MyRemoteInterfaceServant(); orb.connect(mri);
CORBAServer.javaCORBAServer.java // 取得命名的環境（ naming context ） org.omg.CORBA.Object objRef = orb.resolve_initial_references("NameService"); NamingContext ncRef = NamingContextHelper.narrow(objRef); // 對物件命名 NameComponent nc = new NameComponent("MyRemoteInterface", ""); NameComponent path[] = {nc}; ncRef.rebind(path, mri);
CORBAServer.javaCORBAServer.java // 等待 client 的連結 java.lang.Object sync = new java.lang.Object();
synchronized(sync) { sync.wait(); }
}
catch (Exception e)
{ System.err.println("ERROR: "+e);
e.printStackTrace(System.out);
}
CORBAServer.javaCORBAServer.java class MyRemoteInterfaceServant extends _MyRemoteInterfaceImplBase { public String getRemoteIP() { InetAddress address = null; try { address = InetAddress.getLocalHost(); } catch(Exception e) {} return address.toString(); } }
ClientClient 端程式端程式在以下的程式中描述了使用一個遠端
CORBA 物件的方法，透過一個 name
server 以 look up 物件名稱的方式，實際取得其 CORBA 物件的指標（ reference ），
然後再呼叫（ invoke ）所需的 method 。
Client.java Client.java
import Example.*;
import org.omg.CosNaming.*;
import org.omg.CORBA.*;
Client.java Client.java public class Client
{ public static void main(String args[])
{
try {
ORB orb = ORB.init(args, null);
org.omg.CORBA.Object objRef =
orb.resolve_initial_references("NameService")
NamingContext ncRef =
NamingContextHelper.narrow(objRef);
Client.java Client.java // 利用物件名稱取得其指標 NameComponent nc = new
NameComponent("MyRemoteInterface", "");
NameComponent path[] = {nc};
MyRemoteInterface mri = MyRemoteInterfaceHelper.narrow(ncRef.res
olve(path));
// 呼叫遠端物件並且列印出其結果 System.out.println(mri.getRemoteIP());
Client.java Client.java catch(Exception e)
{
System.out.println("ERROR : "+e);
e.printStackTrace(System.out);
}
執行程式執行程式 Compile 所有程式碼 javac *.java Example/*.java 啟動 name server
tnameserv -ORBInitialPort 1050 啟動 server 程式 java HelloServer -ORBInitialPort 1050 啟動 client 程式 java HelloClient -ORBInitialPort 1050
The default value is 900
參考資料參考資料 Clemens Szyperski, "Component Software,"
Addison-wesley, 1998. Z. Yang, K. Duddy, "CORBA: A Platform for
Distributed Object Computing," http://www.omg.org/corba/beginners.html, 1997.
"CORBA Overview," http://pent21.infosys.tuwien.ac.at/Research/Corba/OMG/arch2.htm, 1997
Success StorySuccess StoryMartin
NTUIM
Who establish Who establish CORBACORBA
OMG OMG (Object Management Group)
1989 年由七家公司贊助成立為非營利組織目的為推廣 OO 概念及訂定 OO 標準目前成果 : CORBA, UML, CWM
Developmet in Developmet in CORBACORBA1991 年 , CORBA 規格被提出
1995 年 , CORBA 規格更新為 2.0 版
目前 , CORBA 2.4 版為最新版本
未來 , CORBA 3 即將出爐
CORBA 3CORBA 3Internet Integration
Firewall Specification
Interoperable Name Service
Quality of Service Control Asynchronous Messaging and QoS Control
Minimum, Fault-Tolerant, Real-Time CORBA
CORBAcomponents Package CORBAcomponents and CORBAscripting
CORBA-based CORBA-based softwaresoftwareOrbix - IONAVisibroker - InpriseJava IDL - SunSOB - IBMOLE COM - MicrosoftPDO - NeXT
Who use CORBAWho use CORBA AT&T American Airlines Boeing Commercial Airplanes Group Cisco Systems, Inc. CNN Interactive Nokia Telecomunications Harvard University NASA Hubble Space Telescope The SABRE Group ……
Why They Use Why They Use CORBACORBA
Distribution and Object Oriented
Industry StandardInteroperabilityReliabilityScalabilitySecurity
Cisco Systems, Inc.Cisco Systems, Inc.IPCIPC (Internetworking Product
Center)B to B 電子商務架構處理企業 47% 的訂單主要來自 Web, 其次來自私人 EDI 網路每天 1000 萬美金的訂貨量
Cisco Systems, Inc.Cisco Systems, Inc.舊有舊有 IPCIPC 的的 WebWeb 架構架構
CGI 程式以 C 和 Perl 為主8 套以上的 CGI 程式與資料庫連結負荷量接近極限
Nelson Carbonell(CEO of Alta Software) said :
“There hasn’t been a lot of thought put into the architecture!”
Cisco Systems, Inc.Cisco Systems, Inc.改造改造 IPCIPC
和 Alta Software 合作以 Java/CORBA 為基本架構將舊系統完全翻新原本多為 Solaris 使用者 , 因此技術人員迅速地熟稔 Java/CORBA 架構
Cisco Systems, Inc.Cisco Systems, Inc.成果成果
穩定性高高度延展性可管理性高和 ERP 系統 (Oracle) 相連結提供客製化服務
CNN InteractiveCNN InteractiveCNN’s websitesCNN’s websites
CNN.com
AllPolitics.com
CNN.com/CustomNews
CNNSI.com
CNNEnEspanol.com
CNN.passen.se
CNNemPortugues.com
Mirror sites: europe.cnn.com, japan.cnn.com
CNN InteractiveCNN Interactive網站流量網站流量 (1998(1998 年年 66 月月 ))
每分鐘 15000 - 25000 人次每個禮拜有 7700 萬個網頁供人參觀每個月有 1150 萬不同的人來參觀當時每個月還有 9% 的成長
CNN InteractiveCNN Interactive內部情況內部情況
使用 Solaris Server
程式設計師多用 C++ , Java
記者做無效率的工作
CNN InteractiveCNN Interactive發展發展 Distributed Web-publishing Distributed Web-publishing
SystemSystem
選擇 CORBA
和 IONA 合作採用 Orbix 環境 Java-based 使用者介面
CNN InteractiveCNN Interactive
TemplatesTemplatesTemplatesCNN
GeneratorHTMLHTMLHTML
IRCNN
ContentServers
CNN InteractiveCNN Interactive
CNN
Reuters
AP
ClassifierWire Services
Event Channel
CNN InteractiveCNN InteractiveCNN : “We deliver products one distributed component at a time , and then we build on those component”
Video System Wires Posting System Prioritizer UI
Magic Mover UI
Publisher Service Priority Service
Distributed Systems Generation Service Content Service
CNN InteractiveCNN Interactive成果成果
程式重用性高物件技術更純熟系統延展性高企業經營更進步
NIKENIKE當時情形 (1997 年 7 月 )
16000 名員工90 億美金的營收25 年內快速成長對 IT 的急迫性
NIKENIKE原本 IT 架構
EZBridgeDB2 MVS
SunOS
SolarisOracle
Non PC Client
FTP RPC
InternetX.25
NIKENIKE改造
選擇 CORBA
和 IONA 合作採用 Orbix 環境淘汰 SunOS
Client 端加入 win95 PC
NIKENIKE改造後 IT 架構
DB2 MVS
SolarisOracle
Mac
FTP Orbix
InternetX.25
Win95 PC
Orbix CTP
NIKENIKE改造成果
採用標準的溝通機制將 Client 端順利轉換為 win95 PC
移除有 Y2K 問題的元件富延展性的架構
NIKENIKE
Just do it !
Reuse legacy code
Remove an unwanted machine type
Install a new front-end client
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