java - 操作 ArrayList 并访问另一个类的方法

Question

我有一个名为“游乐园编程项目”的学校项目

需要创建四个类:

1. 门票 - 模特入场券
2. 商品 - 礼品店出售的商品模型
3. 游乐园 - 跟踪门票和商品库存/销售
4. WaldenAmusementPark - 测试程序

AmusementPark 类是我需要帮助的地方 - 我了解按照说明需要发生什么，但我不清楚如何访问 Ticket 和 Merchandise 中定义的 getter/setter 方法和 ArrayList 以使事情发生 - 我正在阅读指南，观看视频但无法使其工作？:

我已经在下面粘贴了我的代码(例如它的样子) - 任何指导都值得赞赏 不寻找要编写的实际代码 - 只是为了消除我的困惑。提前致谢。

----------------机票舱位----------------------------------

import java.util.*;

public class Ticket {

    //Ticket Class models admission tickets


    //Instance Variables called for in the instructions
    private long number;
    private String category;
    private String holder;
    private Date date;
    private double price;
    private boolean purchased;


    // Constructor Ticket -- The instructions did not call for instance field "number" as a parameter and left "purchased" out of the UML???
    public Ticket (long number, String category, String holder, Date date, double price, boolean purchased){      
        this.number = number;               //Stores unique ticket ID Number
        this.category = category;           //Stores adult, child, or senior
        this.holder = holder;               //Stores name of purchaser
        this.date = date;                   //Stores admission date for the ticket
        this.price = price;                 //Stores price of the ticket
        this.purchased = purchased;         //Stores true if purchased, false if reserved 
    }  // End Brace Constructor Ticket


    // MUTATOR METHODS..............................................

    // setPrice Mutator Method
    public void setPrice(double price){
        this.price = price;
    }  // End Brace setPrice

    //changePurchaseStatus Mutator Method
    public void setchangePurchaseStatus(boolean newStatus){
        this.purchased = newStatus;
    } // End Brace changePurchasedStatus



    // ACCESSOR METHODS.............................................

    //getnumber Accessor Method
    public long getnumber(){
        return number;
    }

    //getcategory Accessor Method
    public String getcategory(){
        return category;
    }

    //getholder Accessor Method
    public String getholder(){
        return holder;
    }

    //getdate Accessor Method
    public Date getdate(){
        return date;
    }

    //getprice Accessor Method
    public double getprice(){
        return price;
    }

    //getpurchased Accessor Method
    public boolean getpurchased(){
        return purchased;
    }


}  // End Brace Ticket Class

--------------------------MERCHANDISE CLASS------------------------------

public class Merchandise {


    //Instance Variables called for in the instructions
    private long ID;                            //ID of specific merchandise item 
    private String category;                    //Stores type of item (T-Shirt, Sweatshirt, Stuffed Animal) - if invalid display "Unknown"
    private String description;                 //Stores description of item
    private double price;                       //Stores price of item
    private boolean instock;                    //True = in stock  False = on order


    // Constructor Merchandise
    public Merchandise(long ID, String category, String description, double price, boolean instock){
         this.ID = ID;
         this.category = category;
         this.description = description;
         this.price = price;
         this.instock = instock;
    } // End Brace Constructor Merchandise



    // MUTATOR METHODS..............................................

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

    public void setInstock(boolean newStatus){   
        this.instock = newStatus;
    }



    // ACCESSOR METHODS.............................................

    public long getID(){
        return ID;
    }

    public String getcategory(){  
        return category;
    }

    public String getdescription(){
        return description;
    }

    public double getprice(){
        return price;
    }

    public boolean getinstock(){
        return instock;
    }


    // toString Method.............................................
    @Override
    public String toString(){
        return("Merchandise ID:" + "\t" + this.ID + "\n" + "Merchandise Category:" + "\t" + this.category + "\n" 
        + "\t" + "Merchandise Description:" + "\t" + this.description + "$" + this.price + "\t" 
        + "In-Stock Status" + "\t" + this.instock);
    }



} //End Brace Merchandise Class


------------------------AMUSEMENT PARK CLASS---------Where I Need Help!!--------
import java.util.ArrayList;

import java.util.Date;

public class AmusementPark {

    //Instance Variables called for in the instructions
    private String name = "Walden Gift Shop";   // Assigned a value that I think is needed to support "getName" Accessor Method 
    private Date date;                          // Not called for in the instruction but I believe it is needed


    //ArrayLists
    public static ArrayList<Ticket> tickets = new ArrayList<Ticket>();                  //Stores ticket objects
    public static ArrayList<Merchandise> merchandise = new ArrayList<Merchandise>();    //Stores Merchandise objects

    //  Stores ArrayList of type Date called "ticketDate" that has all dates for which tickets are still available 
    //  This ArrayList was not clearly called for in the instructions but is required to return dates for which tickets are still available - 
    //  if no tickets are available return empty list
/** public ArrayList<Date> ticketDate(){  
    ArrayList<Date> ticketDate = new ArrayList<Date>();
    Date.(2014, 03, 01);
    }  */

    // Constructor AmusementPark
    public AmusementPark(String name){  //How should I be referencing / using the ArrayLists tickets & merchandise in the constructor?????? 
        this.name = name;
    }


    // ACCESSOR METHODS.............................................

    public String getName(){        // Returns the name of the amusement park shop
        return name;
    }



//---------------------  Have 3 getters to return various Ticket data - Need to fix the stubs for them shown below----------------------

    // Need to fix this getTicketDates getter
/** public getTicketDates(){        //Returns an ArrayList<Date> of all dates tickets are still available
        return                  
    } */

    // Need to fix this getTickets getter
/** public Date getTickets(){       // Returns an integer indicating number of tickets available for specified date
        return date;
    } */


    // Need to fix this getTicket getter
/** public long getTicket (long id){        //Returns Ticket number / ID that matches the specified ticket
        Ticket myTicketID = new Ticket();
            id.getnumber();
    }*/

//---------------------------END the 3 "getMerchandise" getters----------------------------------------------------------------------



//---------------------  Have 3 "getMerchandise" getters to define - Need to fix the stubs for them shown below----------------------

    // Need to fix this getMerchandise getter
/** public getMerchandise(){                    //Returns an Arraylist<Merchandise> of all inventory - if no match return empty list
      return              ;
    } */

    //Need to fix this getMerchandise getter
/** public getMerchandise (String category){    //Returns a list of Merchandise objects whose category matches the specified (e.g., T-Shirts), no match return empty list
        return   
    }*/

    //Need to fix this getMerchandise getter
    /** public getMerchandise (long id){        //Returns the merchandise item that matches the specified id number, if not match return null
        return
    }*/

//---------------------------END the 3 "getMerchandise" getters----------------------------------------------------------------------



    //Need to fix this addTicket Mutator method
/** public addTicket (Ticket) { // Adds a new Ticket to the inventory of AmusementPark Class    
    } */

    //Need to fix this buyMerchandise Mutator method
/** public buyMerchandise (String id){ //Removes a Merchandise object from teh list of merchandise of the AmusementPark Class, if no match throw exception  
    } */


    //Need to fix this buyTicket Mutator method
/** public buyMerchandise (String id){ //Removes a Ticket object from the list of ticket items of the AmusementPark Class - If not match throw exception    
    } */






}  // End Brace AmusementPark Class

Answer 1

您需要在需要的地方实例化一个 Ticket 对象。

Ticket yourTickecObject = new Ticket(constructor parameters);

然后调用getter即可获取数据

int price = yourTicketObject.getPrice(); 

以及设置数据的 setter

yourTicketObject.setPrice(someValue);

ArrayList也是一样，ticket中声明:

ArrayList<someTipe> yourArrayListName = new ArrayList<someTipe>();

setter/getter :

完整数组列表:

public ArrayList getYourArrayListName(){
  return this.yourArrayListName;
}

具体项目:

public yourArrayListType getItem(index){
  return this.yourArrayListName.get(index)
}

设置者:

如果您想添加一项:

public void addObjectToYourArrayListName(SomeValidType argument){
   this.yourArrayListName.add(argument);
}

如果你想设置ArrayList:

public void setYourArrayListName(ArrayList<someValidType> argument){
   this.yourArrayListName = argument;
}

要访问您的数组列表:

设置者:

添加一个项目:

yourTicketObject.addObjectToYourArrayListName(SomeValidType argument)

添加完整的ArrayList:

yourTicketObject.setYourArrayListName(ArrayList<someValidType>)

setter/getter :

获取完整数组列表:

Arraylist<someType> someName = yourTicketObject.getYourArrayListName()

获取具体索引:

YourArrayListType variableName = yourTicketObject.getItem(index)

所有这些代码都是抽象的，您可以在任何适合的地方使用它，注意变量的类型。

希望这有帮助