Mega Code Archive
Thread accuracy
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import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.text.DecimalFormat;
import javax.swing.JButton;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.border.EmptyBorder;
public class SecondCounterMain extends JPanel {
private SecondCounter sc = new SecondCounter();
private JButton startB = new JButton("Start");
private JButton stopB = new JButton("Stop");
public SecondCounterMain() {
stopB.setEnabled(false);
startB.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
startB.setEnabled(false);
Thread counterThread = new Thread(sc, "Counter");
counterThread.start();
stopB.setEnabled(true);
stopB.requestFocus();
}
});
stopB.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
stopB.setEnabled(false);
sc.stopClock();
startB.setEnabled(true);
startB.requestFocus();
}
});
JPanel innerButtonP = new JPanel();
innerButtonP.setLayout(new GridLayout(0, 1, 0, 3));
innerButtonP.add(startB);
innerButtonP.add(stopB);
JPanel buttonP = new JPanel();
buttonP.setLayout(new BorderLayout());
buttonP.add(innerButtonP, BorderLayout.NORTH);
this.setLayout(new BorderLayout(10, 10));
this.setBorder(new EmptyBorder(20, 20, 20, 20));
this.add(buttonP, BorderLayout.WEST);
this.add(sc, BorderLayout.CENTER);
}
public static void main(String[] args) {
SecondCounterMain scm = new SecondCounterMain();
JFrame f = new JFrame("Second Counter");
f.setContentPane(scm);
f.setSize(320, 200);
f.setVisible(true);
f.addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent e) {
System.exit(0);
}
});
}
class SecondCounter extends JComponent implements Runnable {
private volatile boolean keepRunning;
private Font paintFont = new Font("SansSerif", Font.BOLD, 14);
private volatile String timeMsg = "never started";
private volatile int arcLen = 0;
public SecondCounter() {
}
public void run() {
runClock();
}
public void runClock() {
DecimalFormat fmt = new DecimalFormat("0.000");
long normalSleepTime = 100;
long nextSleepTime = normalSleepTime;
int counter = 0;
long startTime = System.currentTimeMillis();
keepRunning = true;
while (keepRunning) {
try {
Thread.sleep(nextSleepTime);
} catch (InterruptedException x) {
// ignore
}
counter++;
double counterSecs = counter / 10.0;
double elapsedSecs = (System.currentTimeMillis() - startTime) / 1000.0;
double diffSecs = counterSecs - elapsedSecs;
nextSleepTime = normalSleepTime + ((long) (diffSecs * 1000.0));
if (nextSleepTime < 0) {
nextSleepTime = 0;
}
timeMsg = fmt.format(counterSecs) + " - "
+ fmt.format(elapsedSecs) + " = "
+ fmt.format(diffSecs);
arcLen = (((int) counterSecs) % 60) * 360 / 60;
repaint();
}
}
public void stopClock() {
keepRunning = false;
}
public void paint(Graphics g) {
g.setColor(Color.black);
g.setFont(paintFont);
g.drawString(timeMsg, 0, 15);
g.fillOval(0, 20, 100, 100); // black border
g.setColor(Color.white);
g.fillOval(3, 23, 94, 94); // white for unused portion
g.setColor(Color.blue); // blue for used portion
g.fillArc(2, 22, 96, 96, 90, -arcLen);
}
}
}
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