squish.java

java多线程编程实例_Source

import java.awt.*;
import java.awt.image.*;
import java.awt.geom.*;
import javax.swing.*;

public class Squish extends JComponent {
	private Image[] frameList;
	private long msPerFrame;
	private volatile int currFrame;

	private Thread internalThread;
	private volatile boolean noStopRequested;

	public Squish(
				int width,
				int height,
				long msPerCycle, 
				int framesPerSec, 
				Color fgColor
			) {

		setPreferredSize(new Dimension(width, height));

		int framesPerCycle = 
				(int) ( ( framesPerSec * msPerCycle ) / 1000 );
		msPerFrame = 1000L / framesPerSec;

		frameList = 
			buildImages(width, height, fgColor, framesPerCycle);
		currFrame = 0;

		noStopRequested = true;
		Runnable r = new Runnable() {
				public void run() {
					try {
						runWork();
					} catch ( Exception x ) {
						// in case ANY exception slips through
						x.printStackTrace(); 
					}
				}
			};

		internalThread = new Thread(r);
		internalThread.start();
	}

	private Image[] buildImages(
				int width, 
				int height, 
				Color color,
				int count
			) {

		BufferedImage[] im = new BufferedImage[count];

		for ( int i = 0; i < count; i++ ) {
			im[i] = new BufferedImage(
					width, height, BufferedImage.TYPE_INT_ARGB);

			double xShape = 0.0;
			double yShape = 
				( (double) ( i * height ) ) / (double) count;

			double wShape = width;
			double hShape = 2.0 * ( height - yShape );
			Ellipse2D shape = new Ellipse2D.Double(
						xShape, yShape, wShape, hShape);

			Graphics2D g2 = im[i].createGraphics();
			g2.setColor(color);
			g2.fill(shape);
			g2.dispose();
		}

		return im;
	}

	private void runWork() {
		while ( noStopRequested ) {
			currFrame = ( currFrame + 1 ) % frameList.length;
			repaint();

			try {
				Thread.sleep(msPerFrame);
			} catch ( InterruptedException x ) {
				// reassert interrupt
				Thread.currentThread().interrupt(); 
				// continue on as if sleep completed normally
			}
		}
	}

	public void stopRequest() {
		noStopRequested = false;
		internalThread.interrupt();
	}

	public boolean isAlive() {
		return internalThread.isAlive();
	}

	public void paint(Graphics g) {
		g.drawImage(frameList[currFrame], 0, 0, this);
	}
}