java 23 种设计模式-09-java 组合模式(Composite Pattern)

目录

组合模式

组合模式(Composite Pattern)使得用户对单个对象和组合对象的使用具有唯一性。

将对象组合成树形结构以表示【部分-整体】的层次结构。

实际案例

类信息概览：

定义

• Component.java

package com.ryo.design.pattern.note.composite;/**** @author bbhou* @date 2017/8/11*/
public abstract class Component {
    private String name;public Component(String name) {this.name = name;}public String getName() {return name;}/*** add one compoent* @param component*/public abstract void add(Component component);/*** remove one compoent* @param component*/public abstract void remove(Component component);/*** display the component info;* @param depth*/public abstract void display(int depth);}

• Composite.java

package com.ryo.design.pattern.note.composite;import java.util.LinkedList;
import java.util.List;/**** @author bbhou* @date 2017/8/11*/
public class Composite extends Component {
    /*** 用于存放子节点*/private List<Component> children = new LinkedList<>();/*** 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。* @param name*/public Composite(String name) {super(name);}@Overridepublic void add(Component component) {this.children.add(component);}@Overridepublic void remove(Component component) {this.children.remove(component);}@Overridepublic void display(int depth) {//1.itselfStringBuilder stringBuilder = new StringBuilder();for(int i = 0; i < depth; i++) {stringBuilder.append("-");}System.out.println(stringBuilder.toString()+" "+getName());//2.childrenfor(Component component : this.children) {component.display(depth+2);}}
}

• Leaf.java

package com.ryo.design.pattern.note.composite;/**** @author bbhou* @date 2017/8/11*/
public class Leaf extends Component {
    public Leaf(String name) {super(name);}@Overridepublic void add(Component component) {System.out.println("can't add child to leaf.");}@Overridepublic void remove(Component component) {System.out.println("can't remove child from leaf.");}@Overridepublic void display(int depth) {StringBuilder stringBuilder = new StringBuilder();for(int i = 0; i < depth; i++) {stringBuilder.append("-");}System.out.println(stringBuilder.toString()+" "+getName());}
}

测试

• Main.java

/** DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.* Copyright (c) 2012-2018. houbinbini Inc.* design-pattern All rights reserved.*/package com.ryo.design.pattern.note.composite;/*** <p> </p>** <pre> Created: 2018/5/16 下午8:11 </pre>* <pre> Project: design-pattern </pre>** @author houbinbin* @version 1.0* @since JDK 1.7*/
public class Main {
    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);}}

• 测试结果

- root --- Leaf A --- Leaf B --- Composite X ----- Leaf XA ----- Leaf XB ----- Composite XY ------- Leaf XYA ------- Leaf XYB

实现方式

UML & Code

UML

UML 图示如下

Code

代码地址

组合模式

系列导航

系列导航