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();
}
}
}
