Swing/AutoRepeatTimer のバックアップ(No.4)

class AutoRepeatHandler extends MouseAdapter implements ActionListener {
  private final Timer autoRepeatTimer;
  private final BigInteger extent;
  private final JLabel view;
  private JButton arrowButton;

  public AutoRepeatHandler(int extent, JLabel view) {
    super();
    this.extent = BigInteger.valueOf(extent);
    this.view = view;
    autoRepeatTimer = new Timer(60, this);
    autoRepeatTimer.setInitialDelay(300);
  }
  @Override public void actionPerformed(ActionEvent e) {
    Object o = e.getSource();
    if (o instanceof Timer) {
      if (Objects.nonNull(arrowButton)
          && !arrowButton.getModel().isPressed()
          && autoRepeatTimer.isRunning()) {
        autoRepeatTimer.stop();
        arrowButton = null;
      }
    } else if (o instanceof JButton) {
      arrowButton = (JButton) e.getSource();
    }
    BigInteger i = new BigInteger(view.getText());
    view.setText(i.add(extent).toString());
  }
  @Override public void mousePressed(MouseEvent e) {
    if (SwingUtilities.isLeftMouseButton(e)
        && e.getComponent().isEnabled()) {
      autoRepeatTimer.start();
    }
  }
  @Override public void mouseReleased(MouseEvent e) {
    autoRepeatTimer.stop();
    arrowButton = null;
  }
  @Override public void mouseExited(MouseEvent e) {
    if (autoRepeatTimer.isRunning()) {
      autoRepeatTimer.stop();
    }
  }
}