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。

类图如下所示

关键类代码及注释如下

abstract class AbstractProductVector {  
    //抽象商品向量
    private String[] productName;  
      
    public AbstractProductList(String[] productName) {  
        this.productsName = productsName;  
    }  
      
    public String[] getProductsName(){  
        return this.productsName;  
    }  
    public abstract AbstractIterator getIterator();  
}  

public interface AbstractIterator {  
    //迭代器接口
    public void next();  
    public boolean isLast();  
    public void previous();  
    public boolean isFirst();  
    public String getNextItem();  
    public String getPreviousItem(); 
	public String getCurrentItem(); 
}  

class MyIterator implements AbstractIterator{  
    //商品类迭代器
    private String[] productName;  
	private int index;
      
    public MyIterator(AbstractProductVectoe vect) {  
        // 用商品类来初始化构造函数 
        productsName = vect.getProductName(); 
		index = 0;  
    }  
       
    public void next() {  
        // TODO Auto-generated method stub    
            index=(index+1)%productName.length; 
    }  
  
    public boolean isLast() {  
        // TODO Auto-generated method stub  
        return (index == productName.length-1);  
    }  
   
    public void previous() {  
        // TODO Auto-generated method stub  
        index=(index-1)%productName.length; 
    }  
  
    public boolean isFirst() {  
        // TODO Auto-generated method stub  
        return index==0;  
    }  
  
     
    public String getNextItem() {   
        return productName[(index+1)%productName.length];  
    }  
   
    public String getPreviousItem() {  
        // TODO Auto-generated method stub  
       public String getCurrentItem() {   
        return productName[index];  
    } 
    
}  

class ProductVector extends AbstractProductVector{  
    //商品类
    public ProductVector(String[] productName) {  
        super(productName);  
    }  
  
    public AbstractIterator getIterator() {  
        // TODO Auto-generated method stub  
        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。

类图如下所示

关键代码及注释如下

public abstract class Command {
	//抽象命令类
	protected BoardScreen bs = new BoardScreen();
    public abstract void execute();
}

public class createCommand extends Command {
    //create命令
    public void execute() {
        bs.create();
    }
}

public class openCommand extends Command {
    //open
    public void execute() {
        bs.open();
    }
}

public class editCommand extends Command {
    //edit命令
    public void execute() {
        bs.edit();
	}
}

public class MenuItem {
	//菜单项，充当调用者的角色
    private Command command;
    public MenuItem(Command c){
        this.setCommand(c);
    }
    public void setCommand(Command c){
            command = c;
    }
    public void click(){
        command.execute();
    }
}

public class BoardScreen {
	//界面类，充当接收者的角色
    public void open(){
        System.out.println("打开BoardScreen");
    }
    public void create(){
        System.out.println("新建BoardScreen");
    }
    public void edit(){
        System.out.println("编辑BoardScreen");
    }
}

public class Menu {
	//客户端
    private List<MenuItem> MenuItems = new ArrayList<MenuItem>();
    public void addMenuItem(MenuItem mi){
        MenuItems.add(mi);
    } 
    public void click(){
        //打开菜单项
    }
}
 

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。

类图如下所示

关键类代码及注释如下

public abstract class ChatRoom
{
	//抽象聊天室类
    public abstract void register(Member member);
    public abstract void sendText(String from,String to,String message);
	public abstract void sendImg(String from,String to,String message);
}

public class ChatGroup extends ChatRoom
{
	public void register(Member mem)
	{
		//注册
	}
	public void sendText(String from, String to ,String message)
	{
		//发送消息
	}
	public void sendImg(String from, String to, String img)
	{
		//发送图片
	}
}


public abstract class Member 
{ 
	//抽象成员类
	protected String name;  
	protected ChatRoom chatroom; 
	public Member(String name) 
	{ 
	this.name=name; 
	}  
	public String getName() 
	{  
	return name; 
	} 
	public void setName(String name) 
	{ 
	this.name=name; 
	} 
} 

public class DiamondMember extends Member
{
	//钻石会员
	public DiamondMember(String name)
	{
		super(name);
	}
	
	public void sendText(String to,String message)
	{
		super.room.sendText(this.name,to,message);
	}
	
	public void sendImg(String to,String message)
	{
		super.room.sendImg(this.name,to,img);
	}
}

public class CommonMember extends Member
{
	//普通会员
	public CommonMember(String name)
	{
		super(name);
	}
	
	public void sendText(String to,String message)
	{
		super.room.sendText(this.name,to,message);
	}
	
	public void sendImg(String to,String message)
	{
		System.out.printIn("普通会员不能发送图片");
	}
}

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。

类图如下所示

关键类代码及注释如下

public abstract class DiscountStrategy
{
	//抽象折扣类
	public abstract double count(int amount,double price);
}

public class ComputerDiscountStrategy extends DiscountStrategy
{
	//计算机类折扣策略
	public double count(int amount,double price)
	{
		return amount*price*0.9;
	}
}

public class LanguageDiscountStrategy extends DiscountStrategy
{
	//语言类折扣策略
	public double count(int amount,double price)
	{
		return amount*(price-2);
	}
}

public class NovelDiscountStrategy extends DiscountStrategy
{
	//小说折扣策略
	public double count(int amount,double price)
	{
		return amount*price-(amount*price)/100*15;
	}
}
public class NulDiscountStrategy extends DiscountStrategy
{
	//不打折
	public double count(int amount,double price)
	{
		return amount*price;
	}
}
public class BookOrder
{
	//购买清单
	private int bookID;
	private double price;
	private String type;
	private int amount;
	private DiscountStrategy strategy;
	
	public void setDiscountStrategy()
	{
		if(this.type.equals("computer"))
		{
			this.strategy=new ComputerDiscountStrategy();
		}
		else if(this.type.equals("language"))
		{
			this.strategy=new LanguageDiscountStrategy();
		}else if(this.type.equals("novel"))
		{
			this.strategy=new NovelDiscountStrategy();
		}else
		{
			this.strategy=new NullDiscountStrategy();
		}
	}
	
	public double getOrderMoney()
	{
		double bill=this.strategy.count(this.amount,this.price);
	}
}
public class BookCart
{        //购物车
	private ArrayList<BookOrder> list=new ArrayList<BookOrder> ();
	public void addBookOrder(BookOrder order)
	{
		list.add(order);
	}
	public void deleteBookOrder(BookOrder order)
	{
		list.remove(order);
	}
	public double payBill()
	{
		double totalMoney=0;
		for(int i=0;i<list.size;i++)
		{
			totalMoney+=list.get(i).getOrderMoney();
		}
	}
}