import java.awt.Color;

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

public class JProgressBarDemo
{
	// Create a JFrame, JPanel, and JProgressBar
	private JFrame frame = new JFrame();
	private JPanel panel = new JPanel();
	JProgressBar progressBar = new JProgressBar();

	// Set where the Progress Bar will start (visually)
	static final int MIN_BAR_VALUE = 0;
	static final int MAX_BAR_VALUE = 100;

	public static void main(String args[])
	{
		new JProgressBarDemo();
	}

	public JProgressBarDemo()
	{
		// Set the properties of the JProgressBar
		progressBar.setSize(250, 20);
		progressBar.setLocation(25, 45);
		progressBar.setForeground(Color.BLACK);
		progressBar.setBackground(Color.RED);

		// Set the point at which the Progress Bar begins moving
		progressBar.setMinimum(MIN_BAR_VALUE);
		progressBar.setMaximum(MAX_BAR_VALUE);

		// Set the properties of the JPanel
		panel = new JPanel();
		panel.setLayout(null);
		panel.setBackground(Color.LIGHT_GRAY);

		// Set the properties of the JFrame
		frame.setLayout(null);
		frame.setResizable(false);
		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		frame.setSize(300, 150);
		frame.setTitle("Demo:  JProgressBar");
		frame.setLocationRelativeTo(null);

		// Add the JProgressBar to the JPanel; then add the JPanel to
		// the JFrame; then make the JFrame visible
		panel.add(progressBar);
		frame.setContentPane(panel);
		frame.setVisible(true);

		// Use a loop and a task delay to advance through the Progress Bar
		for (int i = MIN_BAR_VALUE; i <= MAX_BAR_VALUE; i++)
		{
			// For the scheduled task below, all variables must be declared
			// 'final' so that they cannot change while the task is being
			// processed
			final int value = i;
			try
			{
				// Update the GUI of the Progress Bar asynchronously (allow other
				// tasks to be run concurrently) on the AWT event dispatching
				// thread after all pending AWT events have been processed
				// http://docs.oracle.com/javase/6/docs/api/javax/swing/SwingUtilities.html
				SwingUtilities.invokeLater(new Runnable()
				{
					public void run()
					{
						progressBar.setValue(value);
					}
				});
				java.lang.Thread.sleep(80); // Sleep (pause) for 80 milliseconds
			}
			catch (InterruptedException e)
			{
				// Ignore any errors that occur
			}
		}
	}
}