java_设计模式_组合模式_CompositePattern（20160812）

//Component : 组合中的对象声明接口，在适当的情况下，实现所有类共有接口的默认行为。声明一个接口用于访问和管理 Component 的子部件。
abstract class Component {
    protected String name;
    
    public Component(String name) {
        this.name = name;
    }
    
    public abstract void Add(Component c);
    public abstract void Remove(Component c);
    public abstract void Display(int depth);
}



//Leaf : 表示叶节点对象。叶子节点没有子节点。
class Leaf extends Component {

    public Leaf(String name) {
        super(name);
    }

    @Override
    public void Add(Component c) {
        System.out.println("Can not add to a leaf");
    }

    @Override
    public void Remove(Component c) {
        System.out.println("Can not remove from a leaf");
    }

    @Override
    public void Display(int depth) {
        String temp = "";
        for (int i = 0; i ) {
            temp += ‘-‘;
        }
        System.out.println(temp + name);
    }

    

}


//Composite : 定义枝节点行为，用来存储子部件，在 Component 接口中实现与子部件相关的操作。例如 Add 和 Remove。
class Composite extends Component {

    private List children = new ArrayList();
    
    public Composite(String name) {
        super(name);
    }


    @Override
    public void Add(Component c) {
        children.add(c);
    }

    @Override
    public void Remove(Component c) {
        children.remove(c);
    }

    @Override
    public void Display(int depth) {
        
        String temp = "";
        
        for (int i = 0; i ) {
            temp += ‘-‘;
　　　　}

        System.out.println(temp + name);

        for (Component c : children) {
            c.Display(depth + 2);
        }

    }

}



//Client : 通过 Component 接口操作结构中的对象。
public class CompositePattern {

    public static void main(String[] args) {

        Composite root = new Composite("root");

        root.Add(new Leaf("Leaf A"));

        root.Add(new Leaf("Leaf B"));

        

        Composite compX = new Composite("Composite X");

        compX.Add(new Leaf("Leaf XA"));

        compX.Add(new Leaf("Leaf XB"));

        root.Add(compX);


        Composite compXY = new Composite("Composite XY");

        compXY.Add(new Leaf("Leaf XYA"));

        compXY.Add(new Leaf("Leaf XYB"));

        compX.Add(compXY);


        root.Display(1);
    }
}