Java Swing也惊艳之二：环环相套

    一、序言

    关于“Java做不好桌面”的争论已经由来已久。虽然Swing和Java2D已经有超过十年的历史，也有JIDE、JGoodies、TWaver等不少开源Swing组件，但是用Java做桌面程序仍然不是一件轻松的事。本《Java也惊艳》系列文章，就是想通过一些简单生动的例子，和大家一起认识Java、探索Swing.其实你只需要多一点创意、多一点耐心，你的Java程序也可以“惊艳”！本文就带您一起进入Java的惊艳之旅。

    二、立体套管效果

    在网络通讯中，经常要表达协议之间的“承载”关系。例如，IP协议作为高层协议可以承载在SDH上，也可以承载在ATM协议上。同样，IP作为协议还可以承载更多的高层协议，例如Voice over IP，甚至电信中Everything over IP的概念。在表现上，用相互嵌套的立体套管来表现协议的“承载”是再合适不过了（如下图）。

    具体实现很简单，主要代码如下：

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

import  twaver. * ; 

public   class  PipleComponent  extends  JComponent { 

     public   void  paint(Graphics g) { 
        Graphics2D g2d  =  (Graphics2D) g; 
        g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON); 
        Shape parentHollowShape = createPiple(g2d, 100 , 100 , 200 , 200 ,TWaverUtil.getRandomColor(), null ); 
        createPiple(g2d, 120 , 120 , 280 , 40 ,TWaverUtil.getRandomColor(),parentHollowShape); 
        createPiple(g2d, 130 , 170 , 310 , 40 ,TWaverUtil.getRandomColor(),parentHollowShape); 
        createPiple(g2d, 140 , 220 , 290 , 50 ,TWaverUtil.getRandomColor(),parentHollowShape); 
        createPiple(g2d, 130 , 190 , 300 , 30 ,TWaverUtil.getRandomColor(),parentHollowShape); 
    } 

     private  Shape createPiple(Graphics2D g2d, int  x,  int  y,  int  width,  int  height,Color color,Shape parentHollowShape) { 
         if (parentHollowShape != null ){ 
            Rectangle bounds = parentHollowShape.getBounds(); 
            Rectangle rightClip = new  Rectangle(bounds.x + bounds.width / 2 ,bounds.y, 3000 ,bounds.height); 
            Area clip = new  Area(parentHollowShape); 
            clip.add( new  Area(rightClip)); 
            g2d.setClip(clip); 
        } 
         int  circleWidth  =  height / 3 ; 
        GradientPaint paint  =   new  GradientPaint(x, 
                                                y, 
                                                color.brighter(), 
                                                x, 
                                                y  +  ( int ) (height  *   0.65 ), 
                                                color.darker(), 
                                                 true ); 
        g2d.setPaint(paint); 
        Ellipse2D.Double leftCircle  =   new  Ellipse2D.Double(x  -  circleWidth  /   2 , y, circleWidth, height); 
        Ellipse2D.Double rightCircle  =   new  Ellipse2D.Double(x  +  width  -  circleWidth  /   2 , y, circleWidth, height); 
        
         int  thickness = 4 ; 
        Ellipse2D.Double rightHollowCircle  =   new  Ellipse2D.Double(rightCircle.getX() + thickness, 
            rightCircle.getY() + thickness, 
            rightCircle.getWidth() - thickness * 2 , 
            rightCircle.getHeight() - thickness * 2 ); 
        
        Rectangle rect  =   new  Rectangle(x, y, width, height); 
        Area area  =   new  Area(leftCircle); 
        area.add( new  Area(rect)); 
        area.subtract( new  Area(rightCircle)); 
        g2d.fill(area); 
        g2d.setColor(color.darker()); 
        g2d.fill(rightCircle); 
        
        paint  =   new  GradientPaint(x, 
                                  y, 
                                  Color.darkGray, 
                                  x, 
                                  y  +  ( int ) (height  *   0.4 ), 
                                  Color.lightGray, 
                                   true ); 

        g2d.setPaint(paint); 
        g2d.fill(rightHollowCircle); 
        
        g2d.setClip( null ); 
        
         return  rightHollowCircle; 
    } 

     public   static   void  main(String[] args) { 
        JFrame frame  =   new  JFrame(); 
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
        frame.setSize( 800 ,  600 ); 
        frame.add( new  PipleComponent()); 
        frame.setVisible( true ); 
    } 
}