设计模式第三次作业

设计模式第三次作业

1、要求：某商品管理系统的商品名称存储在一个字符串数组中，现需要自定义一个双向迭代器（MyIterator）实现对该商品名称数组的双向（向前和向后）遍历。使用Iterator模式来设计。

类图：

代码：

//抽象迭代器接口，定义向前和向后的双向遍历
public interface Iterator {
    void forward();
    void backward();
    bollean hasNext();
    object currentItem();
}



//抽象聚合类，存储对象并定义创建迭代器对象的接口
public interface Aggregate {
    Iterator createIterator();
}



//具体聚合类，实现创建迭代器的接口，返回一个与具体聚合对象对应的具体迭代器实例
public class MyAggregate implements Aggregate{
    private String[] name={"clothes","shoes","makeup","bags"};//名称存在一个字符串数组中
    public Iterator createIterator(){
        return new MyIterator();
    } //返回具体迭代器实例
    private class MyIterator implements Iterator{ 
        private int currentIndex;
        public void forward(){
            currentIndex=name.length;
            for(int i=currentIndex;i>0;i--){
                System.out.println(name[i]);
                currentIndex--;
            }
        }
        public void backward(){
            currentIndex=0;
            for(int i=currentIndex;i<name.length;i++){
                System.out.println(name[i]);
                currentIndex++;
            }
            
        }
        public boolean hasNext(){
            return currentIndex==name.length;
        }
        public String currentItem(){
            return name[currentIndex];
        }
    }
}



//具体迭代器，完成对对象的遍历，同时在进行遍历时跟踪其当前位置
public class MyIterator implements Iterator{
    private Aggregate strings;
    public MyIterator(MyAggregate strings){
        this.strings=strings;
    }
    private int currentIndex;
    public void forward(){}
    public void backward(){}
    public boolean hasNext(){}
    public String currentItem(){}
    
}

2、要求：某公司欲开发一个基于Windows平台的公告板系统，系统提供主菜单（Menu）其中有菜单项（MenuItem）。通过Menu类的addMenuItem()方法增加菜单项。菜单项的打开方法是click(）,每个菜单项包含一个抽象命令类，具体命令类包括OpenCommand()、CreateCommand()、EditCommand()等，命令类具有一个execute()方法，用于调用公告板系统界面类（BoardScreen()）的open()、create()、edit()）等方法。使用Command模式来设计。

类图：

代码：

//声明执行操作的接口
public abstract class AbstractCommand{
    public void excute();
}


//ConcreteCommamd调用接受者相应操作以实现execute
public abstract  class MenuOpenCommand extends AbstractCommand{
    private BoardScreen boardscreen;
    public CreateCommand(BoardScreen boardscreen){
       this.boardscreen=boardscreen;
    }
    //调用公告板系统界面类BoardScreen的open方法
    public void excute(){
        boardscreen.open();
    }
}
public abstract  class MenuEditCommand extends AbstractCommand{
    private BoardScreen boardscreen;
    public MenuEditCommand (BoardScreen boardscreen){
       this.boardscreen=boardscreen;
    }
    //调用公告板系统界面类BoardScreen的open方法
    public void excute(){
        boardscreen.edit();
    }
}
public abstract  class MenuCreateCommand extends AbstractCommand{
    private BoardScreen boardscreen;
    public MenuCreateCommand (BoardScreen boardscreen){
       this.boardscreen=boardscreen;
    }
    //调用公告板系统界面类BoardScreen的open方法
    public void excute(){
        boardscreen.create();
    }
}


//Invoker请求的发送者
public class MenuItem{
     private abstructCommand command;
     public MenuItem(abstructCommand command){
        this.command=command; 
     }
     public void click(){
         this.command.execute();
     }
}


//Receive实施与执行一个请求相关的操作
public class Menu{
    private MenuItem menuitem;
    public void addMenuItem(MenuItem menuitem){
        menu.add(menuitem);
    }
    public void clickMenuItem(){
        menuitem.click();
    }
    
}


//Client创建一个具体命令对象并设定其接受者
public class Client{
    public static void main(String args[]){
        Menu menu=new Menu();//菜单
         BoardScreen bs = new BoardScreen();
        abstructCommand  oc=new MenuOpenCommand (bs );
        MenuItem item1=new MenuItem(oc);
        menu.addMenuItem(item1);
        menu.clickMenuItem();//点击菜单
      abstructCommand  ec=new MenuEditCommand (bs );
        MenuItem item2=new MenuItem(ec);
        menu.addMenuItem(item2);
        menu.clickMenuItem();//点击菜单
      abstructCommand  cc=new MenCreateCommand (bs );
        MenuItem item3=new MenuItem(cc);
        menu.addMenuItem(item3);
        menu.clickMenuItem();//点击菜单
    }
}

3、要求：某论坛系统欲增加一个虚拟聊天室，允许论坛会员通过该聊天室进行信息交流，普通会员（CommonMember）可以给其他会员发送文本信息，钻石会员（DiamondMember）可以给其他会员发送文本和图片信息。该聊天室可以对不雅字符进行过滤，如“TMD”等字符，还可以对发送图片大小进行控制。使用Mediator模式来设计。

类图：

代码：

//Mediator为各个colleague对象定义通信接口
public abstract  class ChatRoom{
    protected ArrayList members;
    protected void register(Member member){
        members.add(member);
    }
    public abstract void sendText(String sender,String text);
    public abstract void sendPicture(String sender,String picture);
}


//ConcreteMediator实际保持colleague联系
public abstract  class ConcreteChatRoom extends ChatRoom{
    private filterDirtyWords filter;
    private controlPicSize control;
    
    public ConcreteChatRoom(filterDirtyWords filter,controlPicSize control){
        this.filter=filter;
        this.control=control;
    }
    //过滤不雅字符
    public boolean filterDirtyWords(String text){
        if(text.equals("TMD")){return true;}
        else{return false;}
    }
    //对发送图片大小进行控制
    public boolean controlPicSize(String picture){
        if(picture.size>100){return true;}
        else{return false;}
    }
    
    public void sendText(String text){
        if(!filter(text)){//是健康字符才能发送
            System.out.println("send text");
        }
    }
    public void sendPicture(String picture){
        if(!control(picture)){//符合大小的图片才能发送
            System.out.println("send picture");
        }
    }
}

//Colleague为各个colleague定义公共方法
public abstract class Memeber{
    protected ChatRoom chatroom;
    protected String name;
    public Member(String name){
        this.name=name;
        this.chatroom=chatroom;
    }
    public abstract void sendText(String Text);
    
    public abstract void sendPicture(String Picture);



//ConcreteColleague实现定义的各种方法，包括发送文本图片、过滤一些文字和控制图片大小等
public abstract  class CommonMember extends Memeber{
    public CommonMember(String name){
        super(name);
    }
    //普通会员只能发送文本
    public void sendText(){
        chatRoom.sendText(Text);
    }
}


public abstract  class DiamondMember extends Memeber{
    public DiamondMember(String name){
        super(name);
    }
    //钻石会员能发送文本和图片
    public void sendText(){
        chatRoom.sendText(Text);
    }
     public void sendPicture(){
        chatRoom.sendPicture(picture);
    }
}

//用户调用
public class Client {
    public static void main(String[] args) {
        filterDirtyWords filter=new filterDirtyWords();// 创建文本过滤器对象
        controlPicSize control=new controlPicSize();// 创建图片大小控制器对象

        ConcreteChatRoom room = new ConcreteChatRoom(filter, control);// 创建聊天室

        CommonMember commonMember = new CommonMember("lin"); // 普通会员
        room.register(commonMember);// 聊天室注册

        DiamondMember diamondMember = new DiamondMember("xue");// 钻石会员
        room.register(diamondMember);// 聊天室注册
    
        commonMember.sendText("我是普通会员");//普通会员可以发送文本
        diamondMember.sendPicture("pic1");// 钻石会员可以发送图片
        
        diamondMember.sendText("TMD");     // 发送失败
        diamondMember.sendPicture("pic2"); // 超过大小限制发送失败

    }
}

4、要求：设计一个网上书店，对系统中所有的计算机类图书（ComputerBook）每本都有10%的折扣，语言类图书（LanguageBook）每本都有2元的折扣，小说类图书（NovelBook）每100元有15元的折扣。使用Strategy模式来设计。

类图：

代码：

//Strategy定义所有支持的算法的公共接口
public interface BookDiscount {
     public abstract double calculatePrice(double price);
}


//以Strategy接口实现某具体算法
public class ComputerBookDiscount extends BookDiscount {//计算机类图书
    private double price;

    @Override
    public double calculatePrice(double price) {
        return price * 0.9;
    }
}

public class LanguageBookDiscount extends BookDiscount {//语言类图书
    private double price;

    @Override
    public double calculatePrice(double price) {
        return price - 2;
    }
}

public class NovelBookDiscount extends BookDiscount {//小说类图书
    private double price;

    @Override
    public double calculatePrice(double price) {
        return price-(price/100*15);
    }
}


//Context 使用接口调用具体定义的算法
public class Book {//书籍类使用折扣接口调用折扣策略
    private double price;
    private String type;//图书类别
    private BookDiscount bookdiscount;
    
    public Book(String type,double price){
        this.type=type;
        this.price=price;
    }
    
    public void chooseDiscount(String type) {
        if(type.equals("计算机类图书")){
            this.bookdiscount=ComputerBookDiscount;
        }
        else if(type.equals("语言类图书")){
            this.bookdiscount=LanguageBookDiscount;
        }
        if(type.equals("小说类图书")){
            this.bookdiscount=NovelBookDiscount;
        }
    }
    public double calculatePrice(double price) {
        return bookdiscount.calculatePrice(price); 
    }
}

//用户调用
public class Client {
    public static void main(String args[]) {
    
        Book book = new Book();
        BookDiscount  bookdiscount = new ComputerBookDiscount(); 
        BookDiscount  bookdiscount = new LanguageBookDiscount();
        BookDiscount  bookdiscount = new NovelBookDiscount();
        book.chooseDiscount(book.getType());
        double price = book.getCost();
        book.calculatePrice(price);
    
    }
}