Java RMI – 分散オブジェクトの例

package com.techfou.rmiinterface;

import java.rmi.Remote;
import java.rmi.RemoteException;
import java.util.List;

public interface RMIInterface extends Remote {

    Book findBook(Book b) throws RemoteException;
    List<Book> allBooks() throws RemoteException;

}

package com.techfou.rmiinterface;

import java.io.Serializable;

public class Book implements Serializable {

    private static final long serialVersionUID = 1190476516911661470L;
    private String title;
    private String isbn;
    private double cost;

    public Book(String isbn) {
        this.isbn = isbn;
    }

    public Book(String title, String isbn, double cost) {
        this.title = title;
        this.isbn = isbn;
        this.cost = cost;
    }

    public String getTitle() {
        return title;
    }

    public String getIsbn() {
        return isbn;
    }

    public double getCost() {
        return cost;
    }

    public String toString() {
        return "> " + this.title + " ($" + this.cost + ")";
    }

}

package com.mkyong.rmiserver;

import java.rmi.Naming;
import java.rmi.RemoteException;
import java.rmi.server.UnicastRemoteObject;
import java.util.ArrayList;
import java.util.List;
import java.util.function.Predicate;

import com.mkyong.rmiinterface.Book;
import com.mkyong.rmiinterface.RMIInterface;

public class Bookstore extends UnicastRemoteObject implements RMIInterface {

    private static final long serialVersionUID = 1L;
    private List<Book> bookList;

    protected Bookstore(List<Book> list) throws RemoteException {
        super();
        this.bookList = list;
    }

   //The client sends a Book object with the isbn information on it
   //(note: it could be a string with the isbn too)

   //With this method the server searches in the List bookList
   //for any book that has that isbn and returns the whole object
    @Override
    public Book findBook(Book book) throws RemoteException {
        Predicate<Book> predicate = x -> x.getIsbn().equals(book.getIsbn());
        return bookList.stream().filter(predicate).findFirst().get();
    }

    @Override
    public List<Book> allBooks() throws RemoteException {
        return bookList;
    }

    private static List<Book> initializeList() {
        List<Book> list = new ArrayList<>();
        list.add(new Book("Head First Java, 2nd Edition", "978-0596009205", 31.41));
        list.add(new Book("Java In A Nutshell", "978-0596007737", 10.90));
        list.add(new Book("Java: The Complete Reference", "978-0071808552", 40.18));
        list.add(new Book("Head First Servlets and JSP", "978-0596516680", 35.41));
        list.add(new Book("Java Puzzlers: Traps, Pitfalls, and Corner Cases", "978-0321336781", 39.99));
        return list;
    }

    public static void main(String[]args) {
        try {
            Naming.rebind("//localhost/MyBookstore", new Bookstore(initializeList()));
            System.err.println("Server ready");
        } catch (Exception e) {
            System.err.println("Server exception: " + e.getMessage());
        }
    }

}

package com.mkyong.rmiclient;

import java.net.MalformedURLException;
import java.rmi.Naming;
import java.rmi.NotBoundException;
import java.rmi.RemoteException;
import java.util.List;
import java.util.NoSuchElementException;

import javax.swing.JOptionPane;

import com.mkyong.rmiinterface.Book;
import com.mkyong.rmiinterface.RMIInterface;

public class Customer {

    private static RMIInterface look__up;

    public static void main(String[]args) throws
            MalformedURLException, RemoteException, NotBoundException {

        look__up = (RMIInterface) Naming.lookup("//localhost/MyBookstore");

        boolean findmore;
        do {

            String[]options = {"Show All", "Find a book", "Exit"};

            int choice = JOptionPane.showOptionDialog(null, "Choose an action", "Option dialog",
                    JOptionPane.DEFAULT__OPTION,
                    JOptionPane.INFORMATION__MESSAGE,
                    null, options, options[0]);

            switch (choice) {

                case 0:
                    List<Book> list = look__up.allBooks();
                    StringBuilder message = new StringBuilder();
                    list.forEach(x -> {
                        message.append(x.toString() + "\n");
                    });
                    JOptionPane.showMessageDialog(null, new String(message));
                    break;
                case 1:
                    String isbn = JOptionPane.showInputDialog("Type the isbn of the book you want to find.");
                    try {
                        Book response = look__up.findBook(new Book(isbn));
                        JOptionPane.showMessageDialog(null, "Title: " +
                                        response.getTitle() + "\n" + "Cost: $" +
                                        response.getCost(),
                                response.getIsbn(), JOptionPane.INFORMATION__MESSAGE);
                    } catch (NoSuchElementException ex) {
                        JOptionPane.showMessageDialog(null, "Not found");
                    }
                    break;
                default:
                    System.exit(0);
                    break;

            }
            findmore = (JOptionPane.showConfirmDialog(null, "Do you want to exit?", "Exit",
                    JOptionPane.YES__NO__OPTION) == JOptionPane.NO__OPTION);
        } while (findmore);
    }
}

$ javac src/com/mkyong/rmiinterface/RMIInterface.java src/com/mkyong/rmiinterface/Book.java src/com/mkyong/rmiserver/Bookstore.java src/com/mkyong/rmiclient/Customer.java

$ cd src
$ start rmiregistry
$ java com.mkyong.rmiserver.Bookstore

$ cd src
$ java com.mkyong.rmiclient.Customer