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

public interface Iterator {
    public abstract boolean next();
    public abstract boolean previous();
}

public class MyIterator implements Iterator {
    private MyGoodsStore mygoodsstore;
    private int index;
    public MyIterator(MyGoodsStore mygoodsstore) 
    {
        this.mygoodsstore = mygoodsstore;
        this.index = 0;
    }
    @Override
    public boolean next() 
    {
    }
    @Override
    public boolean previous() 
    {
    }
}

public interface GoodsStore {
    public abstract Iterator iterator();
}


public class MyGoodsStore implements GoodsStore {

    private Goods[] goods;

    public MyGoods(int maxSize) {
        this.goods = new Goods[maxSize];

    }

    @Override
    public Iterator iterator() {
        return new MyIterator(this);
    }
}

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。

public class Menu 
{
    private List<MenuItem> myMenuItemList = new ArrayList<>();

    public void addMenuItem(MenuItem menuItem) 
    {
    }

    public void clickMenuItem(int index) 
    {
        menuItemList.get(index).click();
    }
}


public class MenuItem 
{
    private Command command;

    public MenuItem(Command command) 
    {
        this.command = command;
    }

    public void setCommand(Command command) 
    {
        this.command = command;
    }

    public void click() 
    {
        command.execute();
    }
}


public abstract class Command 
{
    public abstract void execute();
}

public class BoardScreen
{
	public bool open()
	{

	}

	public bool create()
	{

	}

	public bool edit()
	{
		
	}
}


public class OpenCommand extends Command 
{

    private BoardScreen boardScreen;

    public OpenCommand(BoardScreen boardScreen) 
    {
        this.boardScreen = boardScreen;
    }

    @Override
    public void execute() 
    {
        boardScreen.open();
    }
}

public class CreateCommand extends Command 
{

    private BoardScreen boardScreen;

    public CreateCommand(BoardScreen boardScreen) 
    {
        this.boardScreen = boardScreen;
    }

    @Override
    public void execute() 
    {
        boardScreen.create();
    }
}


public class EditCommand extends Command 
{

    private BoardScreen boardScreen;

    public EditCommand(BoardScreen boardScreen) 
    {
        this.boardScreen = boardScreen;
    }

    @Override
    public void execute() {
        boardScreen.edit();
    }
}

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。

public abstract class Member 
{
    private String member_name;
    private ChatRoom chat_room;

    public Member(String member_name) 
    {
        this.member_name = member_name;
    }

    public void setRoom(ChatRoom chat_room) 
    {
        this.chat_room = chat_room;
    }

    public String getMemberName() 
    {
        return member_name;
    }

    public boolean sendText(Member receiver, String text)
    {
    }

    public boolean sendImage(Member receiver, String image)
    {
    }
}


public class CommonMember extends Member
{
    public CommonMember(String member_name) 
    {
        super(member_name);
    }

    public boolean sendImage(Member receiver, String image) 
    {
    }
}


public class DiamondMember extends Member 
{
    public DiamondMember(String member_name) 
    {
        super(member_name);
    }
}


public class ChatRoom 
{
    public boolean register(Member member)
    {
        member.setRoom(this);
    }

    public boolean sendText(Member sender, Member receiver, String text)
    {
    }
    public boolean sendImage(Member sender, Member receiver, String image)
    {
    }
}


public class ConcreteChatRoom extends ChatRoom
{
    protected String textFilter(String text)
    {
    }

    protected boolean imageCheck(String image)
    {
    }


    public boolean sendText(Member sender, Member receiver, String text) 
    {
        super.sendText(sender, receiver, textFilter(text));
    }

    public boolean sendImage(Member sender, Member receiver, String image) 
    {
        if(imageCheck(image))
        {
            super.sendImage(sender, receiver, image);
        }
    }

    
}

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。

public abstract class Discount 
{
    public double discount(double price);
}

public class ComputerBookDct extends Discount
{
    public double discount(double price) 
    {
        return 0.9*price;
    }
}


public class LanguageBookDct extends Discount
{
    public double discount(double price) 
    {
        if(price > 2)
            return price-2;
        else return price;
    }

}

public class NovelBookDct extends Discount
{
    public double discount(double price) 
    {
        if(price >= 100) 
            return price-((int)price/100)*15;
        else
            return price;
    }

}



public class BookShop 
{
    private ComputerBookDct computer_book_dct;
    private LanguageBookDct language_book_dct;
    private NovelBookDct novel_book_dct;

    public void setComputerBookDct(ComputerBookDct computer_book_dct) 
    {
        this.computer_book_dct = computer_book_dct;
    }

    public void setLanguageBookDct(LanguageBookDct language_book_dct) 
    {
        this.language_book_dct = language_book_dct;
    }

    public void setNovelBookDct(NovelBookDct novel_book_dct) 
    {
        this.novel_book_dct = novel_book_dct;
    }

    public void showBookPrice(Book book)
    {
        double book_price = book.getPrice();
        if(book instanceof ComputerBook)
        {
            book_price = computer_book_dct.discount(book_price);
        }
        else if(book instanceof LanguageBook)
        {
            book_price = language_book_dct.discount(book_price);
        }
        else if(book instanceof NovelBook)
        {
            book_price = novel_book_dct.discount(book_price);
        }

        System.out.println(book.getClass().getSimpleName()+"  原价格:"+book.getPrice()+"  现价格:"+book_price );
    }
}



public abstract class Book 
{
    private double book_price;

    public double getBookPrice() 
    {
        return book_price;
    }

    public void setBookPrice(double book_price) 
    {
        this.book_price = book_price;
    }
}


public class ComputerBook extends Book 
{
}


public class LanguageBook extends Book 
{
}


public class NovelBook extends Book 
{
}