package mil.navy.nps.testing;

/**
    DatagramTestApplet.java

  A minimal applet designed to demonstrate a problem reading 
  from datagram sockets. This works under Netscape 3.x, but not 
  under Netscape 4.x; it throws an exception on receive().

  The code executes until it does a receive(). It blocks there;
  once a packet actually arrives, a socket exception is thrown
  and execution stops. To duplicate the error, run the TestApplet
  in the browser from the HTML file. The applet will block attempting
  to read from the datagram socket. Then fire up the datagram sender
  on the same machine. The first packet that arrives will cause an
  exception to be thrown.

  I've provided a small datagram sender application to send packets.

  running under Netscape Navigator 3.x requires that you take out
  the references to privilegeManager. Under 3.x, packets from the
  same machine were considered kosher by the security manager, and
  no signed applets or privelige managers were required.

  The socket code is isolated in doSocketStuff(). The rest of the
  applet code is just overhead.

  Environment: Running under NT Workstation 4.0, Netscape Navigator
  4.04, Java 1.1 extensions installed, and codebase principals
  turned on.

*/


import java.applet.*;
import java.awt.*;
import java.io.*;
import java.net.*;


// import netscape.security.*;         // for netscape-style signed applets

public class DatagramTestApplet extends Applet implements Runnable
{
 
public DatagramTestApplet()
	{
		
	}

public String getAppletInfo()
	{
		return "Name: AwtPduViewer\r\n" +
		       "Author: Don McGregor\r\n" +
		       "mcgredo@cs.nps.navy.mil";
	}

  /**
     Applet initialization code
  */

	public void init()
	{

    TextArea       textArea;

    // scrolling text area to display output (lines, width)
    textArea = new TextArea(13,45);
    add(textArea);

    return;
	}

  public void run()
  {
		repaint();
  }

	public void paint(Graphics g)
	{
    this.doSocketStuff();

	}

  public void doSocketStuff()
  {

    DatagramSocket unicastDatagramSocket = null;
    DatagramPacket datagramPacket;
    byte           dataBuffer[] = new byte[1500];
    InetAddress    destAddress;
//    PrivilegeManager  privilegeManager = PrivilegeManager.getPrivilegeManager();
	byte  		   byteArray[];
	
    try
    {
     destAddress     = InetAddress.getLocalHost();
     datagramPacket  = new DatagramPacket(dataBuffer, dataBuffer.length);
     

      // @@@THIS IS NETSCAPE COMMUNICATOR SPECIFIC.  It basically
      // switches on network access for everything under the sun,
      // so you can attach or be attached to random machines on
      // the internet. 

/*
      privilegeManager.enablePrivilege("UniversalMulticast");
      privilegeManager.enablePrivilege("UniversalConnect");
      privilegeManager.enablePrivilege("UniversalAccept");
      privilegeManager.enablePrivilege("UniversalListen");
*/
      unicastDatagramSocket = new DatagramSocket(8004);
      System.out.println("created a socket correctly");
      unicastDatagramSocket.receive(datagramPacket);
      System.out.println("Did a receive() correctly");
      byteArray = datagramPacket.getData();
      
      System.out.println(byteArray[0] + ", " + byteArray[1] + ", " + byteArray[2]);
      
     
    }

    catch (SocketException socketException)
    {
      System.out.println("socket exception error: " + socketException);

      throw new 
          RuntimeException("Exception in DatagramTestApplet. Socket exception thrown.");
    }
    catch(UnknownHostException unkException)  // for getLocalHost() call
    {
      System.out.println("Unknown host exception: " + unkException);
      throw new 
            RuntimeException("Exception in DatagramTestApplet. Unable to look up localhost correctly");
    }
    catch (IOException ioError)
     {
      System.out.println("IO exception error: " + ioError.getMessage());
        throw new 
            RuntimeException("Exception in DatagramTestApplet. IOException thrown.");
     }
  }


}   // end of class AwtPduViewer