ThreadedEchoServer.java Source code

Introduction

Here is the source code for ThreadedEchoServer.java

Source

/*
   This program is a part of the companion code for Core Java 8th ed.
   (http://horstmann.com/corejava)
    
   This program is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.
    
   This program 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 for more details.
    
   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.Scanner;

/**
   This program implements a multithreaded server that listens to port 8189 and echoes back 
   all client input.
   @author Cay Horstmann
   @version 1.20 2004-08-03
*/
public class ThreadedEchoServer {
    public static void main(String[] args) {
        try {
            int i = 1;
            ServerSocket s = new ServerSocket(8189);

            while (true) {
                Socket incoming = s.accept();
                System.out.println("Spawning " + i);
                Runnable r = new ThreadedEchoHandler(incoming);
                Thread t = new Thread(r);
                t.start();
                i++;
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

/**
   This class handles the client input for one server socket connection. 
*/
class ThreadedEchoHandler implements Runnable {
    /**
       Constructs a handler.
       @param i the incoming socket
       @param c the counter for the handlers (used in prompts)
    */
    public ThreadedEchoHandler(Socket i) {
        incoming = i;
    }

    public void run() {
        try {
            try {
                InputStream inStream = incoming.getInputStream();
                OutputStream outStream = incoming.getOutputStream();

                Scanner in = new Scanner(inStream);
                PrintWriter out = new PrintWriter(outStream, true /* autoFlush */);

                out.println("Hello! Enter BYE to exit.");

                // echo client input
                boolean done = false;
                while (!done && in.hasNextLine()) {
                    String line = in.nextLine();
                    out.println("Echo: " + line);
                    if (line.trim().equals("BYE"))
                        done = true;
                }
            } finally {
                incoming.close();
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    private Socket incoming;
}