设计模式|组合模式

组合模式

package computer;

import java.util.ArrayList;

public class Test {
public static void main(String[] args) {
//生成树根，树根上长出两个树叶
Composite composite=new Composite(“root”);
composite.add(new Leaf(“LeafA”));
composite.add(new Leaf(“LeafB”));

	//树根上长出分支，分支上有两片叶子
	Composite c1=new Composite("CompositeX");
	c1.add(new Leaf("LeafAx"));
	c1.add(new Leaf("LeafBx"));
	composite.add(c1);
	
	//分支CompositeX上长出一分支，分支上有两叶
	Composite c2=new Composite("CompositeY");
	c2.add(new Leaf("LeafAxY"));
	c2.add(new Leaf("LeafBxY"));
	c1.add(c2);
	
	//根部长出叶子
	composite.add(new Leaf("LeafC"));
	
	//根部掉落叶子
	Leaf leafd=new Leaf("LeafD");
	composite.add(leafd);
	composite.remove(leafd);
	
	//显示
	composite.printStruct(0);
}

}

//抽象基类
abstract class Component{
protected String name;
public Component(String name) {
this.name=name;
}
//添加
public abstract void add(Component component);
//删除
public abstract void remove(Component component);
//输出
public abstract void printStruct(int d);
}

//叶子类
class Leaf extends Component{

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

public void add(Component component) {
	System.out.println("不能添加分支！");
}

public void remove(Component component) {
	System.out.println("不能删除分支！");
}

//显示
public void printStruct(int d) {
	for(int i=0;i

}

//有枝节点
class Composite extends Component{

//下层节点或叶子
private ArrayList components=new ArrayList();

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

public void add(Component component) {
	components.add(component);
}

public void remove(Component component) {
	components.remove(component);
}

//显示
public void printStruct(int d) {
	for(int i=0;i

}
商品类别树

+服装
+男装
-衬衣
-夹克
+女装
-裙子
-套装

特点：
1、有一个根节点
2、树枝节点
3、叶子结点
根节点和树枝节点都可以包含其他节点，统称为容器节点。
现在需要管理商品类别树，假设要求能实现输出如上商品类别树的结构功能，应该如何实现？

一．不带模式的解决方案：组合对象
import java.util.ArrayList;
import java.util.Collection;

class Leaf{
private String name="";
public Leaf(String name) {
this.name=name;
}
public void printStuct(int d) {
for(int i=0;i System.out.print(" “);
System.out.println(’-’+name);
}
}
class Composite{
private CollectionchildComposite=new ArrayList();
private CollectionchildLeaf=new ArrayList();
private String name=”";
public Composite(String name) {
this.name=name;
}
public void addComposite(Composite c) {
this.childComposite.add©;
}
public void addLeaf(Leaf leaf) {
this.childLeaf.add(leaf);
}
public void printStruct(int d) {
for(int i=0;i System.out.print(" ");
System.out.println(’+’+name);
for(Composite c:childComposite) {
c.printStruct(d+2);
}
for(Leaf leaf:childLeaf) {
leaf.printStuct(d+2);
}
}
}
public class Main{
public static void main(String[] args){
//定义组合对象
Composite root=new Composite(“服装”);
Composite c1=new Composite(“男装”);
Composite c2=new Composite(“女装”);
//定义所有叶子结点
Leaf leaf1=new Leaf(“衬衣”);
Leaf leaf2=new Leaf(“夹克”);
Leaf leaf3=new Leaf(“裙子”);
Leaf leaf4=new Leaf(“套装”);
//按照树的结构来组合组合对象和叶子对象
root.addComposite(c1);
root.addComposite(c2);
c1.addLeaf(leaf1);
c1.addLeaf(leaf2);
c2.addLeaf(leaf3);
c2.addLeaf(leaf4);
root.printStruct(0);
}
}

二．改进
import java.util.ArrayList;

abstract class Component{
protected String name;
public Component(String name) {
this.name=name;
}
public abstract void Add(Component component);
public abstract void Remove(Component component);
public abstract void printStruct(int component);
}

class Leaf extends Component{//叶子结点没有子节点
public Leaf(String name) {
super(name);
}
public void Add(Component component) {
System.out.println(“不能添加分支”);
}
public void Remove(Component component) {
System.out.println(“不能删除分支”);
}
public void printStruct(int d) {
for(int i=0;i System.out.print(" “);
System.out.println(’-’+name);
}
}
class Composite extends Component{
private ArrayListcomponents=new ArrayList();
public Composite(String name) {
super(name);
}
public void Add(Component component) {
components.add(component);
}
public void Remove(Component component) {
components.remove(component);
}
@Override
public void printStruct(int d) {
// TODO Auto-generated method stub
for(int i=0;i System.out.print(” ");
System.out.println(’+’+name);
for(Component component:components) {
component.printStruct(d+2);
}
}
}
public class Main{
public static void main(String[] args){
//定义组合对象
Composite root=new Composite(“服装”);
Composite c1=new Composite(“男装”);
Composite c2=new Composite(“女装”);
//定义所有叶子结点
Leaf leaf1=new Leaf(“衬衣”);
Leaf leaf2=new Leaf(“夹克”);
Leaf leaf3=new Leaf(“裙子”);
Leaf leaf4=new Leaf(“套装”);
//按照树的结构来组合组合对象和叶子对象
root.Add(c1);
root.Add(c2);
c1.Add(leaf1);
c1.Add(leaf2);
c2.Add(leaf3);
c2.Add(leaf4);
root.printStruct(0);
}
}