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：

源码：

public interface MyIterator {
boolean prev();
boolean next();
String curItem();
}

public interface ProductList {
MyIterator getIterator();
}

public class MyProductList implements ProductList{
private String[] products;

public MyProductList(String[] products) {
this.products = products;
}

@Override
public MyIterator getIterator() {
return new MyProductListIterator();
}

private class MyProductListIterator implements MyIterator{
private int curIndex = 0;

@Override
public boolean prev() {
boolean hasPrev = curIndex > 0;
if(hasPrev){
--curIndex;
}
return hasPrev;
}

@Override
public boolean next() {
boolean hasNext = curIndex < products.length -1;
if(hasNext){
++curIndex;
}
return hasNext;
}

@Override
public String curItem() {
return products[curIndex];
}
}

}

2、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：

源码：

public class BoardScreen {
private Menu menu;

public BoardScreen(Menu menu) {
this.menu = menu;
}

public Menu getMenu() {
return menu;
}

public void open(){
System.out.println("BoardScreen open");
}
public void create(){
System.out.println("BoardScreen create");
}
public void edit(){
System.out.println("BoardScreen edit");
}
}

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

public void addMenuItem(MenuItem menuItem){
menuItemList.add(menuItem);
}

public void clickAllItems(){
for (MenuItem menuItem :menuItemList) {
menuItem.click();
}
}
}

public class MenuItem {
private String name;
private Command command;

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

public void click(){
System.out.print("click the menuItem["+name+"]"+" and ");
command.execute();
}
}

public interface Command {
void execute();
}

public class OpenCommand implements Command {
private BoardScreen boardScreen;

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

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

public class EditCommand implements Command {
private BoardScreen boardScreen;

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

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

public class CreateCommand implements Command {
private BoardScreen boardScreen;

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

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

public class BoardScreenTest {
private BoardScreen boardScreen;

@Before
public void init(){
boardScreen = new BoardScreen(new Menu());
boardScreen.getMenu().addMenuItem(new MenuItem("openMenuItem", new OpenCommand(boardScreen)));
boardScreen.getMenu().addMenuItem(new MenuItem("createMenuItem", new CreateCommand(boardScreen)));
boardScreen.getMenu().addMenuItem(new MenuItem("editMenuItem", new EditCommand(boardScreen)));
}

@Test
public void test(){
boardScreen.getMenu().clickAllItems();
}
}

3、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：

源码：

public abstract class Member {
private String name;
private AbstractChatRoom chatRoom;

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

public void setChatRoom(AbstractChatRoom chatRoom) {
this.chatRoom = chatRoom;
}

public String getName() {
return name;
}

public void sendText(Member to, String text){
chatRoom.sendText(this, to, text);
}

public void sendImage(Member to, String image){
chatRoom.sendImage(this, to, image);
}
}

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

@Override
public void sendImage(Member to, String image) {
System.out.println("you need to upgrade to diamond member");
}
}

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

public class AbstractChatRoom {
public void register(Member member){
member.setChatRoom(this);
}

public void sendText(Member from, Member to, String text){
System.out.println(from.getName() +" to " + to.getName() +" : text("+text+")");
}
public void sendImage(Member from, Member to, String image){
System.out.println(from.getName() +" to " + to.getName() +" : image("+image+")");
}
}

public class ChatRoom extends AbstractChatRoom{
@Override
public void sendText(Member from, Member to, String text) {
super.sendText(from, to, filterText(text));
}

@Override
public void sendImage(Member from, Member to, String image) {
if(imageCheck(image)){
super.sendImage(from, to, image);
}
}

protected String filterText(String text){
return text.replace("TMD", "***");
}

protected boolean imageCheck(String image){
return image.length() < 4;
}
}

public class ChatRoomTest {
private Member a;
private Member b;

@Before
public void inti(){
a = new CommonMember("commonMember");
b = new DiamondMember("diamondMember");
AbstractChatRoom chatRoom = new ChatRoom();
chatRoom.register(a);
chatRoom.register(b);
}

@Test
public void test(){
a.sendText(b, "TMD! b");
a.sendImage(b, "i1");
b.sendText(a, "TMD! a");
b.sendImage(a, "i1sdfasdf");
b.sendImage(a, "i1");
}
}

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：

源码：

public interface DiscountStrategy {
public double discount(double price);
}

public class ComputerBookDiscount implements DiscountStrategy{
@Override
public double discount(double price) {
return 0.9*price;
}
}

public class LanguageBookDiscount implements DiscountStrategy{
@Override
public double discount(double price) {
return price-2;
}
}

public class NovelBookDiscount implements DiscountStrategy{
@Override
public double discount(double price) {
return price-price/100*15;
}
}

public class BookShop {
private ComputerBookDiscount computerBookDiscount;
private LanguageBookDiscount languageBookDiscount;
private NovelBookDiscount novelBookDiscount;

public void setComputerBookDiscount(ComputerBookDiscount computerBookDiscount) {
this.computerBookDiscount = computerBookDiscount;
}

public void setLanguageBookDiscount(LanguageBookDiscount languageBookDiscount) {
this.languageBookDiscount = languageBookDiscount;
}

public void setNovelBookDiscount(NovelBookDiscount novelBookDiscount) {
this.novelBookDiscount = novelBookDiscount;
}

public double showPrice(Book book){
double price = book.getPrice();
if(book instanceof ComputerBook){
price = computerBookDiscount.discount(price);
}else if(book instanceof LanguageBook){
price = languageBookDiscount.discount(price);
}else if(book instanceof NovelBook){
price = novelBookDiscount.discount(price);
}

System.out.println(book.getClass().getSimpleName()+"  orig:"+book.getPrice()+"  now:"+price );

return price;
}
}

public class Book {
private double price;

public double getPrice() {
return price;
}

public void setPrice(double price) {
this.price = price;
}
}

public class ComputerBook extends Book {
}

public class LanguageBook extends Book {
}

public class NovelBook extends Book {
}

public class BookShopTest {
private BookShop bookShop;

@Before
public void init(){
bookShop = new BookShop();
bookShop.setComputerBookDiscount(new ComputerBookDiscount());
bookShop.setLanguageBookDiscount(new LanguageBookDiscount());
bookShop.setNovelBookDiscount(new NovelBookDiscount());
}

@Test
public void test(){
Book computerBook = new ComputerBook();
computerBook.setPrice(200);
Book languageBook = new LanguageBook();
languageBook.setPrice(200);
Book novelBook = new NovelBook();
novelBook.setPrice(200);

bookShop.showPrice(computerBook);
bookShop.showPrice(languageBook);
bookShop.showPrice(novelBook);
}
}