结构型模式：Bridge（桥接）

http://zh.wikipedia.org/wiki/%E6%A9%8B%E6%8E%A5%E6%A8%A1%E5%BC%8F

/** "Implementor" */interface DrawingAPI{    public void drawCircle(double x, double y, double radius);} /** "ConcreteImplementor" 1/2 */class DrawingAPI1 implements DrawingAPI{   public void drawCircle(double x, double y, double radius)    {        System.out.printf("API1.circle at %f:%f radius %f\n", x, y, radius);   }} /** "ConcreteImplementor" 2/2 */class DrawingAPI2 implements DrawingAPI{   public void drawCircle(double x, double y, double radius)    {         System.out.printf("API2.circle at %f:%f radius %f\n", x, y, radius);   }} /** "Abstraction" */interface Shape{   public void draw();                                            // low-level   public void resizeByPercentage(double pct);     // high-level} /** "Refined Abstraction" */class CircleShape implements Shape{   private double x, y, radius;   private DrawingAPI drawingAPI;   public CircleShape(double x, double y, double radius, DrawingAPI drawingAPI)   {       this.x = x;  this.y = y;  this.radius = radius;        this.drawingAPI = drawingAPI;   }    // low-level i.e. Implementation specific   public void draw()   {        drawingAPI.drawCircle(x, y, radius);   }      // high-level i.e. Abstraction specific   public void resizeByPercentage(double pct)   {        radius *= pct;   }} /** "Client" */class BridgePattern {   public static void main(String[] args)   {       Shape[] shapes = new Shape[2];       shapes[0] = new CircleShape(1, 2, 3, new DrawingAPI1());       shapes[1] = new CircleShape(5, 7, 11, new DrawingAPI2());        for (Shape shape : shapes)       {           shape.resizeByPercentage(2.5);           shape.draw();       }   }}