Question

Below, you can find the description of your labwork for today. You can also find the expected output of this code in the Application Walkthrough section.

You are going to improve your existing Money & Stock Trading Platform on previous week’s labwork by incorporating Collections.

In previous labworks, you have used arrays for holding Customer and Item objects. For this labwork you need to use ArrayList for holding these objects. So, rather than defining Customer[] array, you need to define an ArrayList<Customer> object.

You also need to change the necessary code when accessing these lists, so that your existing code works without any errors.

I HAVE A CODE LIKE THIS IN JAVA, CAN YOU MODIFY CODE:

package labwork5;

import java.util.Scanner;

enum StockValue {
   AAA("Triple A (top-tier)"), AAB("Double A – B"), ABB("A – Double B"),
   BBB("Triple B (lowest recommended for credibility)"), BBC("Double B – C"), BCC("B – Double C"),
   CCC("Triple C (lowest quality)");

   private String str;

   StockValue(String str) {
       this.str = str;
   }

   public String getValue() {
       return str;
   }
}

public class Stock extends Item {

   private StockValue rating;
   private int numberOfShares;

   public Stock() {
       this(null);
   }

   public Stock(String unrated) {
       super();
       Scanner sc = new Scanner(System.in);
       System.out.print("Please enter company name: ");
       setName(sc.nextLine());
       if (unrated == null) {
           System.out.print("Please enter rating: ");
           rating = StockValue.valueOf(sc.nextLine());
       } else {
           rating = StockValue.valueOf(unrated);
       }
       System.out.print("Please enter stock price: ");
       setPrice(Double.parseDouble(sc.nextLine()));
       System.out.print("Please enter number of the shares: ");
       numberOfShares = Integer.parseInt(sc.nextLine());
       System.out.println();
       System.out.println("ID #" + getID() + " is given for Stock " + getName() + "!");
   }

   public void displayInformation() {
       super.displayInformation();
       System.out.println("Company name is: " + getName());
       System.out.println("Rating is: " + rating.getValue());
       System.out.println("Stock price is: " + getPrice());
       System.out.println("Number of shares is: " + numberOfShares);
   }

   public StockValue getRating() {
       return rating;
   }

   public void setRating(StockValue rating) {
       this.rating = rating;
   }

---

package labwork5;

import java.util.Date;

public class Trade {
  
   private Item item;
   private Date date;

   public Trade(Item item) {
       this.item = item;
       date = new Date();
   }

   public void displayTradeInfo() {
       System.out.println("Trade Date:" + date);
       item.displayInformation();
   }

}

   public int getNumberOfShares() {
       return numberOfShares;
   }

   public void setNumberOfShares(int numberOfShares) {
       this.numberOfShares = numberOfShares;
   }

}
-----

package labwork5;

public class Item {
  
   private static int counter = 0;
   private int ID;
   private String name;
   private double price;
  
   public Item() {
       counter++;
       ID = counter;
   }
  
   public void displayInformation() {
       System.out.println("ID# is " + getID());
   }

   public static int getCounter() {
       return counter;
   }

   public static void setCounter(int counter) {
       Item.counter = counter;
   }

   public int getID() {
       return ID;
   }

   public void setID(int iD) {
       ID = iD;
   }

   public String getName() {
       return name;
   }

   public void setName(String name) {
       this.name = name;
   }

   public double getPrice() {
       return price;
   }

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

}
---

package labwork5;

import java.util.Scanner;

public class StockTest {

   public static void main(String[] args) {

       Customer[] customerArray = new Customer[10];
       Item[] itemArray = new Item[10];

       int cCounter = 0;
       int iCounter = 0;

       Scanner sc = new Scanner(System.in);

       while (true) {
           System.out.println("1. Create a new Customer");
           System.out.println("2. Create a new Item");
           System.out.println("3. Initiate a Trade");
           System.out.println("4. Display all customers");
           System.out.println("5. Display all items");
           System.out.println("0. Exit");
           int choice = sc.nextInt();

           System.out.println();

           if (choice == 1) {
               customerArray[cCounter++] = new Customer();
               System.out.println();
           } else if (choice == 2) {
               System.out.println("1. Create a new Stock");
               System.out.println("2. Create a new Unrated Stock");
               System.out.println("3. Create a new MoneyPair");
               choice = sc.nextInt();
              
               System.out.println();

               if (choice == 1) {
                   itemArray[iCounter++] = new Stock();
                   System.out.println();
               } else if (choice == 2) {
                   itemArray[iCounter++] = new Stock("CCC");
                   System.out.println();
               } else if (choice == 3) {
                   itemArray[iCounter++] = new MoneyPair();
                   System.out.println();
               }
           } else if (choice == 3) {
               System.out.print("Please enter a customer ID: ");
               int cID = sc.nextInt();
               System.out.print("Please enter an item ID: ");
               int sID = sc.nextInt();
               int i, j;
               for (i = 0; i < cCounter; i++) {
                   if (cID == customerArray[i].getId()) {
                       break;
                   }
               }
               for (j = 0; j < iCounter; j++) {
                   if (sID == itemArray[j].getID()) {
                       break;
                   }
               }
               if (i != cCounter && j != iCounter) {
                   Trade tmp = new Trade(itemArray[j]);
                   customerArray[i].setOpenTrade(tmp);
               } else {
                   System.out.println("Given Customer ID or Stock ID is not found!");
               }
               System.out.println();
           } else if (choice == 4) {
               for (int i = 0; i < cCounter; i++) {
                   customerArray[i].displayCustomerInfo();
                   System.out.println();
               }
           } else if (choice == 5) {
               for (int j = 0; j < iCounter; j++) {
                   itemArray[j].displayInformation();
                   System.out.println();
               }
           } else {
               break;
           }

       }

   }

}

Answer 1

well, you have missed to provide some of the classes like Customer.java, MoneyPair.java.

Although I have improvised and set this up for you.I have added collections to StockTest.java as that is the only place it is applicable. please fine below the code. Hope this helps.

 package labwork5; import java.util.ArrayList; import java.util.List; import java.util.Scanner; public class StockTest { public static void main(String[] args) {         Boolean[] present = {false}; List<Customer> customerList = new ArrayList<Customer>(); List<Item> itemList = new ArrayList<Item>(); Scanner sc = new Scanner(System.in); while (true) { System.out.println("1. Create a new Customer"); System.out.println("2. Create a new Item"); System.out.println("3. Initiate a Trade"); System.out.println("4. Display all customers"); System.out.println("5. Display all items"); System.out.println("0. Exit"); int choice = sc.nextInt(); System.out.println(); if (choice == 1) {    customerList.add(new Customer()); System.out.println(); } else if (choice == 2) { System.out.println("1. Create a new Stock"); System.out.println("2. Create a new Unrated Stock"); System.out.println("3. Create a new MoneyPair"); choice = sc.nextInt(); System.out.println(); if (choice == 1) { itemList.add(new Stock()); } else if (choice == 2) { itemList.add(new Stock("CCC")); } else if (choice == 3) { itemList.add(new MoneyPair()); } System.out.println(); } else if (choice == 3) {    present[0]=false; System.out.print("Please enter a customer ID: "); int cID = sc.nextInt(); System.out.print("Please enter an item ID: "); int sID = sc.nextInt(); /** * Assumption: There is always one unique id per customer. * There is always one unique id per item. * * Use streams api along with collections to filter first * the item id of the user, and then go to customer Id of the user * and attach the item to it. */ itemList .stream()     .filter(p -> p.getID() == sID)       .forEach(a -> {customerList.stream()                                          .filter(p -> p.getId() == cID)                                       .forEach(c ->                                                               { c.setOpenTrade(new Trade(a));                                                                  present[0]=true;                                                               });                                      }); if(!present[0]) { System.out.println("Given Customer ID or Stock ID is not found!"); } System.out.println(); } else if (choice == 4) {      //use streams foreach with collections to display customer info.        customerList.stream().forEach(c -> c.displayCustomerInfo()); System.out.println(); } else if (choice == 5) {         //user streams foreach with collections to display information of       //item          itemList.stream().forEach(c -> c.displayInformation()); System.out.println(); } else { break; } } sc.close(); } }

Please find below screenshot/pic too, just in case the code above gets scrambled (even though I have applied formatting from the HomeworkLib website).