组合模式-虚有其表的模式

组合模式：

1.作用：

把多个对象组成树状结构来表示局部与整体，这样用户可以一样的对待单个对象和对象的组合。

2.例子

/** "Component" */
interface Graphic {
 
    //Prints the graphic.
    public void print();
}
 
/** "Composite" */
import java.util.List;
import java.util.ArrayList;
class CompositeGraphic implements Graphic {
 
    //Collection of child graphics.
    private List<Graphic> childGraphics = new ArrayList<Graphic>();
 
    //Prints the graphic.
    public void print() {
        for (Graphic graphic : childGraphics) {
            graphic.print();
        }
    }
 
    //Adds the graphic to the composition.
    public void add(Graphic graphic) {
        childGraphics.add(graphic);
    }
 
    //Removes the graphic from the composition.
    public void remove(Graphic graphic) {
        childGraphics.remove(graphic);
    }
}
 
/** "Leaf" */
class Ellipse implements Graphic {
 
    //Prints the graphic.
    public void print() {
        System.out.println("Ellipse");
    }
}
 
/** Client */
public class Program {
 
    public static void main(String[] args) {
        //Initialize four ellipses
        Ellipse ellipse1 = new Ellipse();
        Ellipse ellipse2 = new Ellipse();
        Ellipse ellipse3 = new Ellipse();
        Ellipse ellipse4 = new Ellipse();
 
        //Initialize three composite graphics
        CompositeGraphic graphic = new CompositeGraphic();
        CompositeGraphic graphic1 = new CompositeGraphic();
        CompositeGraphic graphic2 = new CompositeGraphic();
 
        //Composes the graphics
        graphic1.add(ellipse1);
        graphic1.add(ellipse2);
        graphic1.add(ellipse3);
 
        graphic2.add(ellipse4);
 
        graphic.add(graphic1);
        graphic.add(graphic2);
 
        //Prints the complete graphic (four times the string "Ellipse").
        graphic.print();
    }
}

这个模式太简单了，它有确定的用途，将不同的对象有统一操作方式，不管是符合对象，还是单一对象。

我想它更多的场景特点。太过于虚有其表，以至于从来没有把它放在心上，不会有专门人在这种场景下，定义类名为composite。