設計模式第三次作業

1.要求：某商品管理系統的商品名稱存儲在一個字符串數組中，現需要自定義一個雙向叠代器（MyIterator）實現對該商品名稱數組的雙向（向前和向後）遍歷。使用Iterator模式來設計。

抽象叠代器

public interface AbstractIterator {
    public String next();
    public String last();
    public int hasNext();//擁有查看是否到邊界的功能，包括頭和尾
    public String currentIterator();
}

抽象容器

public interface AbstractStringArray{
    public abstract AbstractIterator createIterator();
}
 

商品容器

public class StringArray implements AbstractStringArray{
    private String[] goods= {
            "milk","cookie","wine","noodles","rice"
    };
    public int getLength() {
        return goods.length;
    }
    public String getItem(int positon) {
        return goods[position];
    }
    public AbstractIterator createIterator() {
        return new MyIterator();
    }
}
 

雙向叠代器

public class MyIterator implements AbstractIterator{
    public MyIterator(StringArray stringArray) {
        this.stringArray=stringArray;
    }
    private StringArray stringArray;
    private int index=0;
    public int hasNext{
        if(index>=stringArray.getLength()&&index<=0) {
            return 0;
        }
        else return 1;
    }
    public String next() {
        if(hasNext==0) {
            return stringArray.getItem(index);
            index++;
        }
    }
    public String last() {
        if(hasNext==0) {
            return stringArray.getItem(index);
            index--;
        }
    }
    public String currentItem() {
        return stringArray.getItem(index);
    }
}
 

客戶類

public class Client{
    StringArray stringArray;
    AbstractIterator iterator=stringArray.createIterator();
    
    public void nextRead() {
        for(int i=0;i<iterator.hasNext();i++) {
            
            System.out.println(iterator.currentIterator());
            iterator.next();
        }
    }
    public void lastRead() {
        for(int i=stringArray.getLength();i<iterator.hasNext();i--) {
            
            System.out.println(iterator.currentIterator());
            iterator.last();
        }
        
    }
}

2.某公司欲開發一個基於Windows平臺的公告板系統，系統提供主菜單（Menu）其中有菜單項（MenuItem）。通過Menu類的addMenuItem()方法增加菜單項。菜單項的打開方法是click(）,每個菜單項包含一個抽象命令類，具體命令類包括OpenCommand()、CreateCommand()、EditCommand()等，命令類具有一個execute()方法，用於調用公告板系統界面類（BoardScreen()）的open()、create()、edit()）等方法。使用Command模式來設計。

抽象命令類

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

接收者boardscreen類

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

具體命令類

public class OpenCommand extends Command{
    private BoardScreen boardScreen=null;
    public OpenCommand(BoardScreen boardScreen) {
        this.boardScreen=boardScreen;
    }
    public void execute() {
        boardScreen.open();
    }
}

public class CreateCommand extends Command{
    private BoardScreen boardScreen=null;
    public CreateCommand(BoardScreen boardScreen) {
        this.boardScreen=boardScreen;
    }
    public void execute() {
        boardScreen.create();
    }
}

public class EditCommand extends Command{
    private BoardScreen boardScreen=null;
    public EditCommand(BoardScreen boardScreen) {
        this.boardScreen=boardScreen;
    }
    public void execute() {
        boardScreen.edit();
    }
}

請求者類

public class MenuItem{
    private Command openCommand=null;
    private Command createCommand=null;
    private Command editCommand=null;
    MenuItem(Command openCommand,Command createCommmand,Command editCommand){
        this.openCommand=openCommand;
        this.createCommand=createCommmand;
        this.editCommand=editCommand;
    }
    public void openC(){
        openCommand.execute();

    }
    public void createC(){
        createCommand.execute();

    }
    public void editC(){
        editCommand.execute();

    }
}

菜單類

public class Menu{
    private List<MenuItem> menuList=new ArrayList<>();
    public void addMenuItem(MenuItem MenuItem) {
        menuList.add(MenuItem);
    }
    public MenuItem getMenuItem(int index) {
        return menuList.get(index);
    }
}

客戶類（測試類）

public class Client{
    public static void main() {
        //接受者
        BoardScreen boardScreen=new BoardScreen();
        Menu menu=new Menu();
        //命令對象
        OpenCommand open=new OpenCommand(boardScreen);
        CreateCommand create=new CreateCommand(boardScreen);
        EditCommand edit=new EditCommand(boardScreen);
        //請求者
        MenuItem menuItem=new MenuItem(open,create,edit);
        menu.addMenuItem(menuItem);
        //測試
        menuItem.createC();
        menuItem.editC();
        menuItem.openC();
        
    }
}

3.某論壇系統欲增加一個虛擬聊天室，允許論壇會員通過該聊天室進行信息交流，普通會員（CommonMember）可以給其他會員發送文本信息，鉆石會員（DiamondMember）可以給其他會員發送文本和圖片信息。該聊天室可以對不雅字符進行過濾，如“TMD”等字符，還可以對發送圖片大小進行控制。使用Mediator模式來設計。

抽象聊天室

public abstract class AbstractLobby {
    public abstract void sendImage();
    public abstract void sendLetter();
}

抽象成員

public class Member{
    private AbstractLobby abstractLobby;
    private String name;
    public String getName() {
        return name;
    }
    Member(AbstractLobby abstractLobby,String name){
        this.abstractLobby=abstractLobby;
        this.name=name;
    }
}

鉆石會員

public class DiamondMember extends Member{
    DiamondMember(AbstractLobby abstractLobby,String name){
        super(abstractLobby,name);
    }
    public void sendImage(String image) {
        System.out.println("DiamondMember "+this.getName()+" send image "+image);
    }
    public void sendLetter(String letter) {
        System.out.println("DiamondMember"+this.getName()+" send message "+letter);
    }
}

普通會員

public class CommonMember extends Member{
    CommonMember(AbstractLobby abstractLobby,String name){
        super(abstractLobby,name);
    }
    public void sendLetter(String letter) {
        System.out.println("CommonMember"+this.getName()+" send message "+letter);
    }
}

聊天室

public class Lobby extends AbstractLobby{
    DiamondMember dm;
    CommonMember cm;
    
    
    private int size=5;
    public void setSize(int size) {
        this.size=size;
    }
    //判斷規範
    public String checkLetter(String letter) {
         letter.replace("TMD","!@#");
         letter.replace("fuck", "!@#");
        return  letter;
    }
        //判斷大小
    public boolean checkImage(String image) {
        if(image.length()>size)
            return false;
        else return true;
    }
    
    public void setDM(DiamondMember dm) {
        this.dm=dm;
    }
    public void setCM(CommonMember cm) {
        this.cm=cm;
    }
    //判斷圖片是否符合限制並發送
    public void sendImage(String image) {
        if(checkImage(image))
            dm.sendImage(image);
        else
            System.out.println("send failed,Too large to send");
    }
        //判斷是否出現敏感詞並發送
    public void sendLetter(String letter,Member member) {
        if(member==dm) {
            dm.sendLetter(checkLetter(letter));
        }
        else
            cm.sendLetter(checkLetter(letter));
    }
}

客戶類

public class Client{
    public static void main(String[] args) {
        Lobby lobby=new Lobby();
        
        DiamondMember diamondMember=new DiamondMember(lobby,"ash");
        CommonMember commonMember=new CommonMember(lobby,"jackle");
        //添加入聊天室
        lobby.setDM(diamondMember);
        lobby.setCM(commonMember);
        xn--wcs23c1yd9t9a76olnr
        lobby.setSize(10);
        //測試
        diamondMember.sendImage("imageSize");
        diamondMember.sendLetter("what the fuck!!!");
        commonMember.sendLetter("what the hell!!!");
    }
}

4.設計一個網上書店，對系統中所有的計算機類圖書（ComputerBook）每本都有10%的折扣，語言類圖書（LanguageBook）每本都有2元的折扣，小說類圖書（NovelBook）每100元有15元的折扣。使用Strategy模式來設計。

折扣策略類

public interface OffStrategy {
    public double paymentCal(double bookPrice);
}

計算機折扣類

public class ComputerBook implements OffStrategy{
    
    public double paymentCal(double bookPrice) {
        return bookPrice*0.9;
    }
    
}

語言書折扣類

public class LanguageBook implements OffStrategy{
    
    public double paymentCal(double bookPrice) {
        return bookPrice-2.0;
    }
    
}

小說折扣類

public class NovelBook implements OffStrategy{
    
    public double paymentCal(double bookPrice) {
        return bookPrice-15*((int)bookPrice/100);
    }
    
}

價格類（context）

public class Price{
    private OffStrategy offStrategy;
    
    public Price(OffStrategy offStrategy) {
        this.offStrategy=offStrategy;
    }
    public void setBookType(OffStrategy offStrategy) {
        this.offStrategy=offStrategy;
    }
    
    public double bill(double bookPrice) {
        return this.offStrategy.paymentCal(bookPrice);
    }
}

客戶類（測試類）

public class Client{
    public static void main(String[] args) {
        OffStrategy computer=new ComputerBook();
        OffStrategy language=new LanguageBook();
        OffStrategy novel=new NovelBook();
        double bookBill=0;
        
        Price price=new Price(computer);
        double bookPrice=price.bill(240);
        bookBill=bookPrice+bookBill;
        System.out.println("bookprice is "+bookPrice);
        
        price.setBookType(language);
        bookPrice=price.bill(400);
        bookBill=bookPrice+bookBill;
        System.out.println("bookprice is "+bookPrice);
        
        price.setBookType(novel);
        bookPrice=price.bill(310);
        bookBill=bookPrice+bookBill;
        
        System.out.println("bookprice is "+bookPrice);
        System.out.println("total price is "+bookBill);
    }
}

設計模式第三次作業