IKH331-07-java-rmi

Java RMI, 17 November 2011

Methods can be called by another JVM on a different host

Interface is remote if it extends Remote Remote object implements a remote

interface and extends UnicastRemoteObject

Pemrograman Terdistribusi 2 Sistem Terdistribusi (IKH331)

Primitive types are passed by value Objects (that are not remote)

They are serialized and then passed by value.

At the other end the objects are deserialized

Any references inside the object are also serialized

Remote Objects

Passed as remote references (stubs)


Obtain a reference for the remote object URL for the remote object is specified as

rmi://host:port/name


public class HiDunia {

public String sayHalo() {

return "Halo dunia!";

}

public static void main (String args[]) {

String response = this.sayHalo();

System.out.println(response); }

}

Pemrograman Terdistribusi Sistem Terdistribusi (IKH331) 5

public class Halo {

public String sayHalo() {

return "Hello, world!";

}

}

public class HaloDunia {

public static void main (String args[]) {

Halo kelas = new Halo();

String response = kelas.sayHalo();

System.out.println(response); }

}


Satu address space

Code segment

Data segment

Stack segment


Proses berbeda

class Halo

class HaloDunia

mungkin berjalan di node yang sama

atau node berbeda

Different address space stub method Remote object


Mendefinisikan remote interface Mengimplementasikan interface (server)

Buat dan ekspor remote object

Registrasi remote object dengan Java RMI registry

Mengimplementasikan client Jalankan server Jalankan client


import java.rmi.Remote;

import java.rmi.RemoteException;

public interface Hello extends Remote {

String sayHello() throws RemoteException;

}


import java.rmi.Remote;

import java.rmi.registry.Registry;

import java.rmi.registry.LocateRegistry;

import java.rmi.RemoteException;

import java.rmi.server.UnicastRemoteObject;

public class Server implements Hello {

public Server() {}

public String sayHello() {

return "Hello, world!";

}


public static void main(String args[]) {

try {

Server obj = new Server();

Hello stub = (Hello)

UnicastRemoteObject.exportObject(obj, 0);

// Bind the remote object's stub in the registry

Registry registry = LocateRegistry.getRegistry();

registry.bind("Hello", stub);

System.err.println("Server ready");

} catch (Exception e) {

System.err.println("Server exception: " +

e.toString());

e.printStackTrace();

}

}

}


import java.rmi.registry.LocateRegistry;

import java.rmi.registry.Registry;

public class Client {

private Client() {}

public static void main(String[] args) {

String host = (args.length < 1) ? null : args[0];

try {

Registry registry = LocateRegistry.getRegistry(host);

Hello stub = (Hello) registry.lookup("Hello");

String response = stub.sayHello();

System.out.println("response: " + response);

} catch (Exception e) {

System.err.println("Client exception: " +

e.toString());

e.printStackTrace();

}

}

} Pemrograman Terdistribusi Sistem Terdistribusi (IKH331) 13

javac –d destDir Server.java

javac –d destDir Client.java

start rmiregistry

java –Djava.rmi.server.codebase=file:destDir/ Server

java –Djava.rmi.server.codebase=file:destDir/ Client


Default pada port 1099 start rmiregistry 2011 Registry reg =

LocateRegistry.getRegistry(2011);


Implementasikan sebuah aplikasi kalkulator sederhana dengan RMI

Client menerima ekspresi matematika (+, x, /, -)

Server mengimplementasikan method-method yang sesuai

Parsing ekspresi matematika dengan StringTokenizer

untuk menentukan method apa yang dipanggil


Kerangka program Client

Baca ekspresi matematika

Tokenize, untuk mendapatkan ekspresi matematik yang digunakan

Jika operatornya +, panggil method RMI penjumlahan()

Jika operatornya x, panggil method RMI perkalian()

dst


Program Server

Implementasikan method-method untuk operasi dasar matematika

int perkalian(int a, int b);

int pembagian(int a, int b);

int penjumlahan(int a, int b);

int pengurangan(int a, int b);


Waktu pengerjaan

Dua pekan (30 November 2011, pukul 12.00 WIB)

By e-mail [email protected]

Subject "IKH331 RMI"

Bonus

Evaluasi ekspresi yang lebih kompleks

3 + 4 x 2

(3 + 4) x 2

Pengumpulan sebelum tenggat waktu Pemrograman Terdistribusi Sistem Terdistribusi (IKH331) 19

mailto:[email protected]

Java RMI Hello World, http://download.oracle.com/javase/6/docs/technotes/guides/rmi/hello/hello-world.html

Vijay Garg, "Concurrent and Distributed Programming in Java"

Source code http://users.ece.utexas.edu/~garg/jbk.html

http://tjerdastangkas.blogspot.com/search/label/ikh331


Kamis, 17 November 2011

IKH331-07-java-rmi

Education

Transcript of IKH331-07-java-rmi