实例解析Java设计模式编程中的适配器模式使用

public class DrawRectangle {//画方 
  public void drawRectangle(String msg) { 
    System.out.println("draw Rectangle: " + msg); 
  } 
} 

public interface IDrawCircle {//画圆的接口 
  void drawCircle(); 
} 

/** 
 * 类适配器 使用对象继承的方式，是静态的定义方式 
 * @author stone 
 * 
 */ 
public class DrawAdapter4Class extends DrawRectangle implements IDrawCircle {//既能画方又能画圆 
 
  @Override 
  public void drawCircle() { 
    System.out.println("DrawAdapter4Class: drawCircle"); 
  } 
   
} 

/** 
 * 对象适配器： 使用对象组合的方式，是动态组合的方式。 
 * 既能画方又能画圆 
 * @author stone 
 * DrawAdapter是适配器，DrawRectangle属于adapter,是被适配者，适配器将被适配者和适配目标（DrawCircle）进行适配 
 * 
 */ 
public class DrawAdapter4Object implements IDrawCircle {//既能画方又能画圆 
   
  private DrawRectangle drawRectangle; 
  public DrawAdapter4Object(DrawRectangle drawRectangle) { 
    this.drawRectangle = drawRectangle; 
  } 
   
  @Override 
  public void drawCircle() { 
    System.out.println("DrawAdapter4Object: drawcircle"); 
  } 
   
  public void drawRectangle(String msg) { 
    drawRectangle.drawRectangle(msg); 
  }  
   
} 

/* 
 * 接口适配器:接口中有抽象方法，我们只想实现其中的几个，不想全部实现， 
 * 所以提供一个默认空实现，然后继承自它，重写实现我们想实现的方法 
 */ 
public interface IDraw { 
  void drawCircle(); 
  void drawRectangle(); 
} 

/* 
 * 接口适配器 的默认实现 
 */ 
public class DefaultDrawAdapter implements IDraw {//画方 画圆 皆为空实现 
 
  @Override 
  public void drawCircle() { 
     
  } 
 
  @Override 
  public void drawRectangle() { 
     
  } 
} 

public class Test { 
  public static void main(String[] args) { 
    //对象适配器 
    DrawAdapter4Object objAdapter = new DrawAdapter4Object(new DrawRectangle()); 
    objAdapter.drawCircle(); 
    objAdapter.drawRectangle(" in DrawAdapter4Object"); 
     
    System.out.println("--------------"); 
     
    //类适配器 
    DrawAdapter4Class clzAdapter = new DrawAdapter4Class(); 
    clzAdapter.drawCircle(); 
    clzAdapter.drawRectangle("in DrawAdapter4Class"); 
     
    System.out.println("--------------"); 
     
    //接口适配器 
    MyDrawAdapter myDrawAdapter = new MyDrawAdapter(); 
    myDrawAdapter.drawCircle(); 
    myDrawAdapter.drawRectangle(); 
  } 
   
  static class MyDrawAdapter extends DefaultDrawAdapter { 
 
    @Override 
    public void drawCircle() { 
      System.out.println("drawCircle in MyDrawAdapter"); 
    } 
     
  } 
} 

DrawAdapter4Object: drawcircle 
draw Rectangle: in DrawAdapter4Object 
-------------- 
DrawAdapter4Class: drawCircle 
draw Rectangle: in DrawAdapter4Class 
-------------- 
drawCircle in MyDrawAdapter