import java.awt.BasicStroke;
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.FlowLayout;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Shape;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.geom.AffineTransform;
import java.awt.geom.Line2D;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;

public class Stoppuhr implements ActionListener {

    private JButton startButt, stopButt, resetButt;
    private UhrPanel panel;

    public Stoppuhr() {
        init();
    }
    
    private void init() {
        JFrame frame = new JFrame("Stopuhr");
        panel = new UhrPanel();
        panel.setRunning(false);
        frame.add(panel, BorderLayout.CENTER);

        startButt = new JButton("start");
        startButt.addActionListener(this);
        stopButt = new JButton("stop");
        stopButt.addActionListener(this);
        resetButt = new JButton("reset");
        resetButt.addActionListener(this);
        JPanel buttPanel = new JPanel(new FlowLayout());
        buttPanel.add(startButt);
        buttPanel.add(stopButt);
        buttPanel.add(resetButt);
        frame.add(buttPanel, BorderLayout.SOUTH);

        frame.setSize(300, 300);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setVisible(true);
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(() -> new Stoppuhr());
    }

    public void actionPerformed(ActionEvent e) {
        if (e.getSource() == startButt) {
            panel.setRunning(true);
        }
        if (e.getSource() == stopButt) {
            panel.setRunning(false);
        }
        if (e.getSource() == resetButt) {
            panel.setIndex(0);
            panel.setRunning(false);
            panel.repaint();
        }
    }
}

class UhrPanel extends JPanel implements Runnable {

	public UhrPanel() {
		start();
	}

	double winkel = Math.PI / -30;
	int index = 0;
	boolean running;
	private Thread thread;

	public void paintComponent(Graphics g) {
		Graphics2D g2d = (Graphics2D) g;
		g2d.setColor(Color.WHITE);
		g2d.fillRect(0, 0, this.getWidth(), this.getHeight());

		AffineTransform at = new AffineTransform();
		at.setToScale(1, -1);
		AffineTransform aff = new AffineTransform();
		aff.setToTranslation(this.getWidth() / 2, this.getHeight() / 2);
		at.preConcatenate(aff);
		g2d.transform(at);

		// Zifferzeichen
		g2d.setColor(Color.RED);
		Line2D.Double ziffer = new Line2D.Double(0, 60, 0, 70);
		Shape zShape;
		for (int i = 0; i < 61; i += 5) {
			at.setToRotation(winkel * i);
			zShape = at.createTransformedShape(ziffer);
			g2d.draw(zShape);
		}

		// Zifferzeichen an den Positionen 12/3/6/9
		g2d.setColor(Color.BLACK);
		g2d.setStroke(new BasicStroke(3));
		Line2D.Double viertel = new Line2D.Double(0, 60, 0, 70);
		Shape qShape;
		for (int i = 0; i < 61; i += 15) {
			at.setToRotation(winkel * i);
			qShape = at.createTransformedShape(viertel);
			g2d.draw(qShape);
		}

		// Zeiger
		g2d.setColor(Color.BLACK);
		Line2D.Double line = new Line2D.Double(0, 0, 0, 50);
		at.setToRotation(winkel * index, 0, 0);
		Shape s = at.createTransformedShape(line);
		g2d.draw(s);

	}

	public void start() {
		if (thread == null) {
			thread = new Thread(this);
			thread.start();
		}
	}

	public void setRunning(boolean running) {
		this.running = running;
	}

	public void setIndex(int i) {
		this.index = i;
	}

	public void run() {
		while (true) {
			if (running) {
				index++;
				index = index > 60 ? 1 : index;
				repaint();
			}
			try {
				Thread.sleep(1000);
			} catch (InterruptedException e) {
				e.printStackTrace();
			}
		}
	}
}