infiniteprogresspanel.java

一个用java编写的服务器,对于学习网络编程的人来说是个很好的例子

    
    /**
     * Starts the waiting animation by fading the veil in, then
     * rotating the shapes. This method handles the visibility
     * of the glass pane.
     */
    public void start() {
        addMouseListener(this);
        setVisible(true);
        ticker = buildTicker();
        animation = new Thread(new Animator(true));
        animation.start();
    }
    
    /**
     * Stops the waiting animation by stopping the rotation
     * of the circular shape and then by fading out the veil.
     * This methods sets the panel invisible at the end.
     */
    public void stop() {
        if (animation != null) {
            animation.interrupt();
            animation = null;
            animation = new Thread(new Animator(false));
            animation.start();
        }
    }
    
    /**
     * Interrupts the animation, whatever its state is. You
     * can use it when you need to stop the animation without
     * running the fade out phase.
     * This methods sets the panel invisible at the end.
     */
    public void interrupt() {
        if (animation != null) {
            animation.interrupt();
            animation = null;
            
            removeMouseListener(this);
            setVisible(false);
        }
    }
    
    public void paintComponent(Graphics g) {
        if (started) {
            int width  = getWidth();
            int height = getHeight();
            
            double maxY = 0.0;
            
            Graphics2D g2 = (Graphics2D) g;
            g2.setRenderingHints(hints);
            
            g2.setColor(new Color(255, 255, 255, (int) (alphaLevel * shield)));
            g2.fillRect(0, 0, getWidth(), getHeight());
            
            for (int i = 0; i < ticker.length; i++) {
                int channel = 224 - 128 / (i + 1);
                g2.setColor(new Color(channel, channel, channel, alphaLevel));
                g2.fill(ticker[i]);
                
                Rectangle2D bounds = ticker[i].getBounds2D();
                if (bounds.getMaxY() > maxY)
                    maxY = bounds.getMaxY();
            }
            
            if (text != null && text.length() > 0) {
                FontRenderContext context = g2.getFontRenderContext();
                TextLayout layout = new TextLayout(text, getFont(), context);
                Rectangle2D bounds = layout.getBounds();
                g2.setColor(getForeground());
                layout.draw(g2, (float) (width - bounds.getWidth()) / 2,
                        (float) (maxY + layout.getLeading() + 2 * layout.getAscent()));
            }
        }
    }
    
    /**
     * Builds the circular shape and returns the result as an array of
     * <code>Area</code>. Each <code>Area</code> is one of the bars
     * composing the shape.
     */
    private Area[] buildTicker() {
        Area[] ticker = new Area[barsCount];
        Point2D.Double center = new Point2D.Double((double) getWidth() / 2, (double) getHeight() / 2);
        double fixedAngle = 2.0 * Math.PI / ((double) barsCount);
        
        for (double i = 0.0; i < (double) barsCount; i++) {
            Area primitive = buildPrimitive();
            
            AffineTransform toCenter = AffineTransform.getTranslateInstance(center.getX(), center.getY());
            AffineTransform toBorder = AffineTransform.getTranslateInstance(45.0, -6.0);
            AffineTransform toCircle = AffineTransform.getRotateInstance(-i * fixedAngle, center.getX(), center.getY());
            
            AffineTransform toWheel = new AffineTransform();
            toWheel.concatenate(toCenter);
            toWheel.concatenate(toBorder);
            
            primitive.transform(toWheel);
            primitive.transform(toCircle);
            
            ticker[(int) i] = primitive;
        }
        
        return ticker;
    }
    
    /**
     * Builds a bar.
     */
    private Area buildPrimitive() {
        Rectangle2D.Double body = new Rectangle2D.Double(6, 0, 30, 12);
        Ellipse2D.Double   head = new Ellipse2D.Double(0, 0, 12, 12);
        Ellipse2D.Double   tail = new Ellipse2D.Double(30, 0, 12, 12);
        
        Area tick = new Area(body);
        tick.add(new Area(head));
        tick.add(new Area(tail));
        
        return tick;
    }
    
    /**
     * Animation thread.
     */
    private class Animator implements Runnable {
        private boolean rampUp = true;
        
        protected Animator(boolean rampUp) {
            this.rampUp = rampUp;
        }
        
        public void run() {
            Point2D.Double center = new Point2D.Double((double) getWidth() / 2, (double) getHeight() / 2);
            double fixedIncrement = 2.0 * Math.PI / ((double) barsCount);
            AffineTransform toCircle = AffineTransform.getRotateInstance(fixedIncrement, center.getX(), center.getY());
            
            long start = System.currentTimeMillis();
            if (rampDelay == 0)
                alphaLevel = rampUp ? 255 : 0;
            
            started = true;
            boolean inRamp = rampUp;
            
            while (!Thread.interrupted()) {
                if (!inRamp) {
                    for (int i = 0; i < ticker.length; i++)
                        ticker[i].transform(toCircle);
                }
                
                repaint();
                
                if (rampUp) {
                    if (alphaLevel < 255) {
                        alphaLevel = (int) (255 * (System.currentTimeMillis() - start) / rampDelay);
                        if (alphaLevel >= 255) {
                            alphaLevel = 255;
                            inRamp = false;
                        }
                    }
                } else if (alphaLevel > 0) {
                    alphaLevel = (int) (255 - (255 * (System.currentTimeMillis() - start) / rampDelay));
                    if (alphaLevel <= 0) {
                        alphaLevel = 0;
                        break;
                    }
                }
                
                try {
                    Thread.sleep(inRamp ? 10 : (int) (1000 / fps));
                } catch (InterruptedException ie) {
                    break;
                }
                Thread.yield();
            }
            
            if (!rampUp) {
                started = false;
                repaint();
                
                setVisible(false);
                removeMouseListener(InfiniteProgressPanel.this);
            }
        }
    }
    
    public void mouseClicked(MouseEvent e) {
    }
    
    public void mousePressed(MouseEvent e) {
    }
    
    public void mouseReleased(MouseEvent e) {
    }
    
    public void mouseEntered(MouseEvent e) {
    }
    
    public void mouseExited(MouseEvent e) {
    }
}