[java-list] Applets que se comunicam

[Nijava]

Pessoal, tenho o exemplo abaixo de uma calculadora, utilizando um único Applet, como eu faria para que os botões da calculadora ficassem separados do resultado, utilizando para isso "Applets que se comunicam"?     Nicéia   // Calculadora import java.awt.*; import java.awt.event.*;   class CalcListener implements ActionListener {     private TextArea display;       protected double ultimoValor = 0, // penultimo valor usado                      valor = 0; // valor mostrado no display     protected char ultimaOp = ' '; //+,-,*,/     protected boolean novoNumero = true, // proximo digito digitado                       ultimoIgual = false; // permite repeticoes     String displayMemo = "";     double decimal = 1; // potencia a multiplicar digitos decimais       CalcListener (TextArea ta)     {         display = ta;     }       private void operacao (String s)     {   displayMemo = s + '\n' + display.getText();   display.setText(displayMemo);  }    private void resultado(double x)  {   valor = x;   displayMemo = x + "" + '\n' + " = " + '\n' + display.getText();   display.setText(displayMemo);  }       private void update (double x)     {      if (x == -1)      {    displayMemo = "";    x = 0;   }   valor = x;   display.setText(String.valueOf(valor) + '\n' + displayMemo);;  }       public void actionPerformed (ActionEvent ev)     {         String label = ev.getActionCommand(); //getActionCommand();         char k = label.charAt(0);         switch(k)         {             case '.':                 if (novoNumero)                 {                     valor = 0;                     novoNumero = false;                 }                 if (decimal ==1) // evita duplo uso                     decimal = 10;                 break;             case '0': case '1': case '2':             case '3': case '4': case '5':             case '6': case '7': case '8': case '9':                 // bug: digitar 0.000...x mostra apenas                 // "0" enquanto x != '0' nao e' digitado                 if (novoNumero)                 {                     valor = 0;                     novoNumero = false;                 }                 if (decimal > 1)                 {                     valor = valor + (k - '0')/decimal;                     decimal *=10;                 }                 else                     valor = valor * 10 + (k - '0');                     update(valor);                     break;               case 'C':                 update (-1);                 decimal = 1;                 break;               case '+': case '-': case '*': case '/':                   ultimaOp = k; novoNumero = true;                 ultimoValor = valor;                 ultimoIgual = false;                 decimal = 1;                 operacao(k + "");                 break;             case '=':                 if (! ultimoIgual)                 {                     // para repetir ultima operacao, troca ultimo valor com valor                     double ultimo = ultimoValor;                     ultimoValor = valor;                     valor = ultimo;                 }                 switch (ultimaOp)                 {                     case '+':                         resultado (valor + ultimoValor);                         break;                     case '-':                         resultado (valor - ultimoValor);                         break;                     case '*':                         resultado (valor * ultimoValor);                         break;                     case '/': // falta testar div por 0                         resultado (valor / ultimoValor);                         break;                 }                 novoNumero = true;                 ultimoIgual = true;                 decimal = 1;         }     } }   public class CalcPad11 extends java.applet.Applet {     protected TextArea display;     private void setButton(Container where,                            GridBagLayout m,                            GridBagConstraints c,                            String name,                            int x, int y,                            int w, int h,                            CalcListener c1)     {         c.gridx = x; c.gridy = y;         c.gridwidth = w; c.gridheight = h;         c.weightx = c.weighty = 1.0;         Button b = new Button (name);         m.setConstraints(b,c);         where.add(b);         b.addActionListener(c1);     }       public void init()     {         display = new TextArea(12,1);         display.setForeground(Color.blue);         display.setBackground(Color.white);         display.setEditable(false);           setLayout (new BorderLayout ());         add ("North",display);           Panel keypad;         add("Center", (keypad = new Panel()));           GridBagConstraints c;         GridBagLayout manager = new GridBagLayout();         keypad.setLayout (manager);           c=new GridBagConstraints();         c.fill = GridBagConstraints.BOTH;           CalcListener c1 = new CalcListener(display);           setButton (keypad,manager,c,"C",0,0,1,1,c1);         setButton (keypad,manager,c,"/",1,0,1,1,c1);         setButton (keypad,manager,c,"*",2,0,1,1,c1);         setButton (keypad,manager,c,"-",3,0,1,1,c1);         setButton (keypad,manager,c,"7",0,1,1,1,c1);         setButton (keypad,manager,c,"8",1,1,1,1,c1);         setButton (keypad,manager,c,"9",2,1,1,1,c1);         setButton (keypad,manager,c,"4",0,2,1,1,c1);         setButton (keypad,manager,c,"5",1,2,1,1,c1);         setButton (keypad,manager,c,"6",2,2,1,1,c1);         setButton (keypad,manager,c,"1",0,3,1,1,c1);         setButton (keypad,manager,c,"2",1,3,1,1,c1);         setButton (keypad,manager,c,"3",2,3,1,1,c1);         setButton (keypad,manager,c,"+",3,1,1,2,c1);         setButton (keypad,manager,c,"=",3,3,1,2,c1);         setButton (keypad,manager,c,"0",0,4,2,1,c1);         setButton (keypad,manager,c,".",2,4,1,1,c1);     } }