Kymotz's Blog

 1package com.elltor.designpattern.compose;
 2
 3public abstract class Component {
 4    protected String componentName;
 5
 6
 7    public Component(String componentName) {
 8        this.componentName = componentName;
 9    }
10
11    public abstract void add(Component component);
12
13    public abstract void remove(Component component);
14
15    public abstract void show(int depth);
16}

 1package com.elltor.designpattern.compose;
 2
 3import java.util.ArrayList;
 4import java.util.List;
 5
 6public class Composite extends Component {
 7    private List<Component> childList = new ArrayList<>();
 8
 9    public Composite(String componentName) {
10        super(componentName);
11    }
12
13    @Override
14    public void add(Component component) {
15        childList.add(component);
16    }
17
18    @Override
19    public void remove(Component component) {
20        childList.remove(component);
21    }
22
23    @Override
24    public void show(int depth) {
25        for(int i=0;i<depth;i++){
26            System.out.print('+');
27        }
28
29        System.out.println(componentName);
30
31        for(int i=0;i<childList.size();i++){
32            childList.get(i).show(depth+2);
33        }
34    }
35}

 1package com.elltor.designpattern.compose;
 2
 3public class Leaf extends Component {
 4    public Leaf(String componentName) {
 5        super(componentName);
 6    }
 7
 8    @Override
 9    public void add(Component component) {
10        System.out.println("叶子节点无法增加节点");
11    }
12
13    @Override
14    public void remove(Component component) {
15        System.out.println("叶子节点无法删除节点");
16    }
17
18    @Override
19    public void show(int depth) {
20        for (int i = 0; i < depth; i++) {
21            System.out.print('+');
22        }
23        System.out.println(componentName);
24    }
25}

 1package com.elltor.designpattern.compose;
 2
 3public class Main {
 4    public static void main(String[] args) {
 5        Composite root = new Composite("树根");
 6        root.add(new Leaf("叶子A"));
 7        root.add(new Leaf("叶子B"));
 8
 9        Composite composite1 = new Composite("节点X");
10        composite1.add(new Leaf("叶子XA"));
11        composite1.add(new Leaf("叶子XB"));
12
13        Composite composite2 = new Composite("节点Y");
14        composite2.add(new Leaf("叶子YA"));
15        composite2.add(new Leaf("叶子YB"));
16
17        composite1.add(composite2);
18        root.add(composite1);
19
20        root.show(0);
21    }
22}
23
24// 打印
25+树根
26+++叶子A
27+++叶子B
28+++节点X
29+++++叶子XA
30+++++叶子XB
31+++++节点Y
32+++++++叶子YA
33+++++++叶子YB