设计模式之组合模式

package com.hml.combination;

public abstract class Component {
    
    private String name;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = 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);

}

package com.hml.combination;

import java.util.ArrayList;
import java.util.List;

public class Composite extends Component {

    private List<Component> children = new ArrayList<Component>();

    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) {
        for (int i = 0; i < children.size(); i++) {
            children.get(i).display(i);
        }

    }

}

package com.hml.combination;

public class Leaf extends Component {

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

    @Override
    public void add(Component c) {
        System.out.println("can‘t add to a leaf");
    }

    @Override
    public void remove(Component c) {
        System.out.println("can‘t remove from a leaf");
    }

    @Override
    public void display(int depth) {
        System.out.println("-" + depth + this.getName());
    }

}

package com.hml.combination;

public class Test {
    public static void main(String[] args) {
        Composite root = new Composite("root");
        root.add(new Leaf("A"));
        root.add(new Leaf("B"));

        Composite com1 = new Composite("com1");
        com1.add(new Leaf("C"));
        com1.add(new Leaf("D"));

        root.add(com1);

        Composite com2 = new Composite("com1");
        com2.add(new Leaf("E"));
        com2.add(new Leaf("F"));

        root.add(com2);

        root.display(1);
    }
}