bankdemo.java

java2参考大全上的例子的源码和自己的理解.

package bankdemo;

/**
 * <p>Title: </p>
 * <p>Description: </p>
 * <p>Copyright: Copyright (c) 2005</p>
 * <p>Company: </p>
 * @author not attributable
 * @version 1.0
 */
class Bank {
  long balance;
  public Bank() {
    balance = 50;
  }

  public void deposite(long amount) {
    if (amount > 0.0) {
      balance += amount;
    }
  }

  void withdrawal(long amount) {
    if (amount > 0.0 && amount <= balance) {
      balance -= amount;
    }
  }

  public long show_balance() {
    return (long) balance;
  }
}

public class BankDemo {
  public static void main(String agrs[]) {
    Bank account1 = new Bank();
    Bank account2 = new Bank();
    account1.deposite(100);
    account2.withdrawal(50);
    account1.show_balance();
    account2.show_balance();
  }

public BankDemo() {
  Bankapp frame = new Bankapp();
  frame.setTitle("Bank Application");
  frame.resize(200, 200);
  frame.show();
}
public void Bankapp() {
  setLayout(new GridLayout(6, 1));
  Label lb = new
      Label("welcome to Bank", Label.CENTER);
  tf = new TextField("0", 15);
  add(lb);
  add(tf);
  b1 = new Button("create account");
  add(b1);
  b2 = new Button("show balance");
  add(b2);
  b3 = new Button("diposite");
  add(b3);
  b4 = new Button("withdrawal");
  add(b4);
  resize(450, 100);
}
public boolean handleEvent(Event evt) {
  switch (evt.id) {
    case Event.WINDOW_DESTROY:
      dispose();
      System.exit(0);
      return true;
    case Event.ACTION_EVENT:
      return action(evt, evt.arg);
    default:
      return super.handleEvent(evt);
  }
}
public boolean action(Event evt, Object arg) {
  if (evt.target instanceof Button) {
    String targetLabel = tf.getText();
    long amount = Long.valueOf(targetLabel).longValue();
    if (arg == "diposite") {
      if (!haveAccount) {
        wb = new WarningBox(this, "create a account first!");
        wb.show();
      }
      else {
        if (amount == 0) {
          wb = new WarningBox(this, "need the amount");
          wb.show();
        }
        else {
          bank.deposite(amount);
          tf.setText("0");
        }
      }
      return true;
    }
    return false;
  }
}
  public void WarningBox(Frame parent, String str) {
    super(parent, "Warning!", true);
    Panel panel = new Panel();
    panel.setLayout(new GridLayout(2, 1));
    panel.add(new Label(str, Label.CENTER));
    panel.add(new Button("OK"));
    add(info_panel);
  }
  public boolean action(Event evt, Object arg) {
    if (evt.target instanceof Button) {
      this.dispose();
      return true;
    }
    return false;
  }
}