机会问题JAVA

//java how to program6.47

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class Wager extends JApplet implements ActionListener {
final int WON=0,LOST=1, CONTINUE=2,over=3;
boolean firstRoll=true;
int sumOfDice=0 ;
int myPoint=0;
int gameStatus=CONTINUE;
int bankbalance=1000;

JLabel die1Label,die2Label,sumLabel,pointLabel;
JTextField die1Field, die2Field, sumField,pointField;
JButton rollButton ;
public void init(){
Container container=getContentPane();
container.setLayout(new FlowLayout());

die1Label=new JLabel ("Diel 1");
container.add(die1Label);
die1Field=new JTextField(10);
die1Field.setEditable(false);
container.add(die1Field);

die2Label=new JLabel ("Diel 2");
container.add(die2Label);
die2Field=new JTextField(10);
die2Field.setEditable(false);
container.add(die2Field);

sumLabel=new JLabel ("sum is");
container.add(sumLabel);
sumField=new JTextField(10);
sumField.setEditable(false);
container.add(sumField);

pointLabel=new JLabel ("point is");
container.add(pointLabel);
pointField=new JTextField(10);
pointField.setEditable(false);
container.add(pointField);

rollButton=new JButton("roll dice");
rollButton.addActionListener(this);
container.add(rollButton);

}

public void actionPerformed(ActionEvent actionEvent){
if(bankbalance>0)
{if(firstRoll){
sumOfDice=rollDice();
switch(sumOfDice){
case 7 :case 11:
gameStatus=WON;
pointField.setText("");
bankbalance+=100;
break;

case 2:case 3:case 12:
gameStatus=LOST;
pointField.setText("");
bankbalance-=100;
break;

default:
gameStatus=CONTINUE;
myPoint=sumOfDice;
pointField.setText(Integer.toString(myPoint));
firstRoll=false;
break;
}
}
else{
sumOfDice=rollDice();
if(sumOfDice==myPoint)
gameStatus=WON;
else
if(sumOfDice==7)
gameStatus=LOST;
}}
else {gameStatus= over;};
displayMessage();
}
public int rollDice()
{
int die1,die2,sum;
die1=1+(int)(Math.random()*6);
die2=1+(int)(Math.random()*6);
sum=die1+die2;
die1Field.setText(Integer.toString(die1));
die2Field.setText(Integer.toString(die2));
sumField.setText(Integer.toString(sum));
return sum;

}
public void displayMessage()
{
if(gameStatus==over){showStatus("sorry ,you are busted!");}
else {if(gameStatus==CONTINUE)
showStatus("roll again");
else {
if(gameStatus==WON)
showStatus("aw c'mon,take a changce"+"your bankbanlance is"+bankbalance);
else
showStatus("player losses."+"your bankbanlance is"+bankbalance);
firstRoll=true;

}}
}
}