Java example source code file (Shadow.java)

This example Java source code file (Shadow.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

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Java - Java tags/keywords

exception, failure, inetsocketaddress, net, network, nio, printstream, serversocket, serversocketchannel, shadow, socket, socketaddress, socketchannel

The Shadow.java Java example source code

/*
 * Copyright (c) 2001, 2010, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

/* @test
 * @bug 4455376
 * @summary Ensure that socket objects obtained from channels
 *          carry the correct address information
 */

import java.io.*;
import java.net.*;
import java.nio.*;
import java.nio.channels.*;


public class Shadow {

    static PrintStream log = System.err;

    private static void dump(ServerSocket s) {
        log.println("getInetAddress(): " + s.getInetAddress());
        log.println("getLocalPort(): " + s.getLocalPort());
    }

    private static void dump(Socket s) {
        log.println("getInetAddress(): " + s.getInetAddress());
        log.println("getPort(): " + s.getPort());
        log.println("getLocalAddress(): " + s.getLocalAddress());
        log.println("getLocalPort(): " + s.getLocalPort());
    }

    private static int problems = 0;

    private static void problem(String s) {
        log.println("FAILURE: " + s);
        problems++;
    }

    private static void check(Socket s) {
        if (s.getPort() == 0)
            problem("Socket has no port");
        if (s.getLocalPort() == 0)
            problem("Socket has no local port");
        if (!s.getLocalAddress().equals(s.getInetAddress()))
            problem("Socket has wrong local address");
    }

    public static void main(String[] args) throws Exception {
        boolean useChannels
            = ((args.length == 0) || Boolean.valueOf(args[0]).booleanValue());
        int port = (args.length > 1 ? Integer.parseInt(args[1]) : -1);

        // open server socket
        ServerSocket serverSocket;
        if (useChannels) {
            ServerSocketChannel serverSocketChannel =
                ServerSocketChannel.open();
            log.println("opened ServerSocketChannel: " +
                      serverSocketChannel);
            serverSocket = serverSocketChannel.socket();
            log.println("associated ServerSocket: " + serverSocket);
        } else {
            serverSocket = new ServerSocket();
            log.println("opened ServerSocket: " + serverSocket);
        }

        // bind server socket to port
        SocketAddress bindAddr =
            new InetSocketAddress((port == -1) ? 0 : port);
        serverSocket.bind(bindAddr);
        log.println("bound ServerSocket: " + serverSocket);

        log.println();

        // open client socket
        Socket socket;
        if (useChannels) {
            SocketChannel socketChannel = SocketChannel.open();
            log.println("opened SocketChannel: " + socketChannel);

            socket = socketChannel.socket();
            log.println("associated Socket: " + socket);
        } else {
            socket = new Socket();
            log.println("opened Socket: " + socket);
        }

        // connect client socket to port
        SocketAddress connectAddr =
            new InetSocketAddress("127.0.0.1",
                                  serverSocket.getLocalPort());
        socket.connect(connectAddr);
        log.println("connected Socket: " + socket);

        log.println();

        // accept connection
        Socket acceptedSocket = serverSocket.accept();
        log.println("accepted Socket: " + acceptedSocket);

        log.println();
        log.println("========================================");

        log.println("*** ServerSocket info: ");
        dump(serverSocket);
        log.println();

        log.println("*** client Socket info: ");
        dump(socket);
        check(socket);
        log.println();

        log.println("*** accepted Socket info: ");
        dump(acceptedSocket);
        check(acceptedSocket);
        log.println();

        if (problems > 0)
            throw new Exception(problems + " tests failed");
    }

}