//In this program, just simply demonstrate how remote methods 
//are called. there are four methods add, subtract, time and divide
//that are resided in different server respectly. Client can invoke
//all of them. 
import java.applet.*;
import java.util.*;
import java.net.*;
import java.awt.*;
import java.awt.event.*;
import java.rmi.*;

public class calclientApplet extends Applet
		 implements ActionListener, ItemListener {
    addInterface ai;
    subtractInterface si;
   timeInterface ti;
   divideInterface di;
   private TextArea ta;
   private TextField tf;
   private Choice ch;
   private TextField tf2;
   private TextField tf3;
   Button b;
   Panel p;
   int i, i2;
   String ss;
   String font="Courier";
   int fSize=16;
   String newLine = System.getProperty("line.separator");

  public void init()
	{
//        int result;
//       String textIP = " ";
//        String serverName = "localhost";
//	InetAddress server;
//	try {
//    server = InetAddress.getByName(serverName);
//	    textIP = toText(server.getAddress());
//	    System.out.println("address is: "+textIP);
//	} catch (java.net.UnknownHostException x) {
//		System.out.println("unknown host!");
//		x.printStackTrace ();}
//	try {
//           addServerImpl ASI = (addServerImpl)
//		//Naming.lookup("//localhost" + "/addServer");
//		Naming.lookup("//" + textIP +  "/addServer");
//           result = ASI.add(3,5);
//          System.out.println("result: "+result);
//	} catch (Exception e) {
//	    System.out.println("calclientApplet exception: " +
//			       e.getMessage());
//	    e.printStackTrace();
//	}

	  Label la=new Label("Show client and all server name, IP address:");
	  add(la);
	  ta=new TextArea(10,55);
	  add(ta);
	  Label la2=new Label("Simple calculator:");
	  add(la2);
	  Panel p=new Panel();
	  tf=new TextField(11);
	  ch=new Choice();
	  ch.addItem("   ");
 	  ch.addItem(" + ");
	  ch.addItem(" - ");
	  ch.addItem(" * ");
	  ch.addItem(" / ");
	  tf2=new TextField(11);
	  tf3=new TextField(11);
	  Button b = new Button("=");
	  p.add(tf);
	  p.add(ch);
	  p.add(tf2);
	  p.add(b);
	  p.add(tf3);
	  add(p);
	  ta.setBackground(Color.green);
	  ta.setFont(new Font(font, Font.BOLD, fSize));
	  la.setFont(new Font(font, Font.BOLD, fSize));
	  la2.setFont(new Font(font, Font.BOLD, fSize));
	  tf.addActionListener(this);
	  tf2.addActionListener(this);
	  tf3.addActionListener(this);
	  b.addActionListener(this);
	  ch.addItemListener(this); 
	try{	  ai=(addInterface)Naming.lookup("//localhost"+"/addserver");
		  si=(subtractInterface)Naming.lookup("//localhost"+"/subtractserver");
		  ti=(timeInterface)Naming.lookup("//localhost"+"/timeserver");
		  di=(divideInterface)Naming.lookup("//localhost"+"/divideserver");
	} 
	catch (NotBoundException e)
	{  System.out.println("Catch NotBoundException error.");
	   System.out.println("NotBoundException"+e.getMessage());
	   e.printStackTrace();
	   System.exit(0);}
	 catch (RemoteException e)
	{  System.out.println("RemoteException"+e.getMessage());
	   e.printStackTrace();
	   System.exit(0);}
	 catch (java.net.MalformedURLException e)
	{  System.out.println("MalformedURL error:"+e.getMessage());
	   e.printStackTrace();
	   System.exit(0);}
}

    static String toText (byte ip[]) {  /* Make portable for 128 bit format */
	StringBuffer result = new StringBuffer ();
	for (int i = 0; i < ip.length; ++ i) {
	    if (i > 0) result.append (".");
	    result.append (0xff & ip[i]);
	}
	return result.toString ();
    }


public void itemStateChanged(ItemEvent e)
{  Object o=e.getItemSelectable();
  if(o==ch)    ss=ch.getSelectedItem();}

public void actionPerformed(ActionEvent e) 
{    if(e.getActionCommand()=="=")
	{      int i=Integer.parseInt(tf.getText());
      		int i2=Integer.parseInt(tf2.getText());
      if(ss==" + "){          
	try{
           int I=ai.add(i,i2);
	   //call remote method in the addServer
           tf3.setText(Integer.toString(I));
           ta.setText("I am a addServer, I invoke the + operation");
          } 
	catch (RemoteException e1) {
             System.out.println("Add Error:" +e1);
             System.exit(0);          }
      }      
	if(ss==" - "){
        try{
           int I=si.subtract(i,i2);
	   //call remote method in the subtractServer
           tf3.setText(Integer.toString(I));
           ta.setText("I am a subtractServer, I invoke the - operation");
        } catch (RemoteException e1) {
             System.out.println("Add Error:" +e1);
             System.exit(0);
         }      }      
	if(ss==" * "){
        try{
           int I=ti.time(i,i2);
	   //call remote method in the timeServer
           tf3.setText(Integer.toString(I));
           ta.setText("I am a timeServer, I invoke time operation");
        } catch (RemoteException e1) {
             System.out.println("Add Error:" +e1);
             System.exit(0);
        }
      }
      if(ss==" / "){
         try{
           int I=di.divide(i,i2);
	   //call remote method in the divideServer
           tf3.setText(Integer.toString(I));
           ta.setText("I am a divideServer, I invoke the / operation");
         } catch (RemoteException e1) {
             System.out.println("Add Error:" +e1);
             System.exit(0);
         }
     }
}}}