import java.net.*; 
import javax.sound.sampled.*; 

public class Phone { 
  private static final AudioFormat FORMAT = new AudioFormat(AudioFormat.Encoding.PCM_SIGNED, 8000.0f, 16, 1, 2, 8000.0f, true); 
  private static final int PORT = 6000; 
  private DatagramSocket socket = null; 

  public static void main(String[] args) { 
    new Phone(args); 
  } 

  public Phone(String[] args) { 
    try {     
      if (args.length == 0) { 
        System.out.println("Waiting!"); 
        socket = new DatagramSocket(PORT);
        DatagramPacket packet = new DatagramPacket(new byte[]{1}, 1);
        socket.receive(packet); 
        socket.connect(packet.getAddress(), PORT); 
      } else { 
        socket = new DatagramSocket(PORT); 
        socket.connect(InetAddress.getByName(args[0]), PORT); 
      } 
    } catch(Exception e) { 
      System.out.println(e);
    } 
    System.out.println("Connected!"); 
    new Recorder(); 
    new Player(); 
  }

  class Recorder extends Thread {   
    public Recorder() {
      start();
    }
 
    public void run() {
      DataLine.Info info = new DataLine.Info(TargetDataLine.class, Phone.FORMAT);
      TargetDataLine line = null;
      try {
        line = (TargetDataLine)AudioSystem.getLine(info); 
        line.open(Phone.FORMAT, line.getBufferSize()); 
      } catch (Exception e) {  
        System.out.println(e); 
      } 
      line.start(); 
      System.out.println("Record started!");

      int frameSizeInBytes = Phone.FORMAT.getFrameSize(); 
      int bufferLengthInFrames = line.getBufferSize() / 8; 
      int bufferLengthInBytes = bufferLengthInFrames * frameSizeInBytes; 
      int minPacketSize = (int)(bufferLengthInBytes / 1.5); 
      int bytesAvailable = 0;
      while(true) { 
        // Send data only when we have a buffer of at least 50%
        if ((bytesAvailable = line.available()) >= minPacketSize) { 
          byte[] data = new byte[bytesAvailable]; 
          line.read(data, 0, bytesAvailable);  
          try { 
            socket.send(new DatagramPacket(data, bytesAvailable));
          } catch(Exception e) { 
            System.out.println(e); 
          } 
        }
      }
    } 
  } 
 
  class Player extends Thread {
    private final int BUFFER = 8000; 
    private final int PACKET_SIZE = 65536;   

    public Player() { 
      start();
    }
   
    public void run() {
      DataLine.Info info = new DataLine.Info(SourceDataLine.class, Phone.FORMAT);
      SourceDataLine line = null;
      try { 
        line = (SourceDataLine)AudioSystem.getLine(info); 
        line.open(Phone.FORMAT, BUFFER); 
      } catch(Exception e) {  
        System.out.println(e); 
      } 
      line.start(); 
      System.out.println("Play started!");

      while(true) { 
        try {
          DatagramPacket packet = new DatagramPacket(new byte[PACKET_SIZE], PACKET_SIZE); 
          socket.receive(packet);
          line.write(packet.getData(), 0, packet.getLength()); 
        } catch(Exception e) { 
          System.out.println(e); 
        } 
      } 
    } 
  }
}