We Keep Coding

Array is just printing out last element [closed]

Closed. This question needs debugging details. It is not currently accepting answers.
Edit the question to include desired behavior, a specific problem or error, and the shortest code necessary to reproduce the problem. This will help others answer the question.
Closed 6 years ago.
Improve this question
I am having this error where it prints out just the last element entered, prints out it the same amount of times as there are elements that are supposed to be in the array.
I have tested it with a System.out.println and the elements that are being added appear to be correct. How do I fix this error?
package stock.control.system;
import java.util.*;
public class StockArrayList implements StockList {
private ArrayList<StockItem> StockItems;
private int index = 0;
private int update;
private int counter = 0;
public StockArrayList() {
StockItems = new ArrayList<StockItem>(counter);
}
#Override
public void addItem(StockItem item) {
StockItem aItem = new StockItem(StockItem.getItemID(),
StockItem.getItemDesc(),
StockItem.getPrice(),
StockItem.getQuantity(),
StockItem.getReOrderLevel());
StockItems.add(counter, aItem);
counter++;
}
#Override
public String formatStockList(){
String temp = StockItem.format();
for (StockItem items : StockItems) {
temp = temp + items.arrayFormat() + "\n";
}
return temp;
}
}
The main method:
public class StockArrayListTester {
public static void main(String[] args) {
StockArrayList Stock = new StockArrayList();
Stock.addItem(new StockItem("P123","1TB Hard drive",75.00,267,50));
Stock.addItem(new StockItem("P125","i7 6800HQ Processor",257.00,113,45));
Stock.addItem(new StockItem("P129","i5 500HQ Processor",127.00,10,45));
Stock.deleteItem("P129");
System.out.printf(Stock.formatStockList());
}
}
the stock item class
package stock.control.system;
import java.util.*;
public class StockItem {
private static String itemID; // Five alpha-numeric characters
private static String itemDesc; // Item description
private static double price; // Item price in pounds sterling
private static int quantity; // Quantity in stock
private static int reOrderLevel; // Level at which to re-order
public StockItem(String itemID, String itemDesc, double price, int quantity, int reOrderLevel) {
this.itemID = itemID;
this.itemDesc = itemDesc;
this.price = price;
this.quantity = quantity;
this.reOrderLevel = reOrderLevel;
}
#Override
public String toString() {
String toString ="[Item ID = " + this.itemID + ", Item Description = " +
this.itemDesc + ", Price = " + this.price + ", Quantity = " +
this.quantity + ", Re Order Level = " + this.reOrderLevel + "]";
return toString;
}
public static String format() {
String format = " STOCK ITEMS"
+ String.format("\n%-10s%-30s%-10s%-12s%-14s%-10s%-30s%-10s%-12s%-14s\n",
"ItemID","Item Description",
"Price","Quantity", "Re Order Level", "\n******",
" ****************"," *****", " ********",
" **************");
return format;
}
public String arrayFormat() {
return String.format("%-10s%-30s%-10s%-12s%-14s",
StockItem.getItemID(),
StockItem.getItemDesc(),
StockItem.getPrice(),
StockItem.getQuantity(),
StockItem.getReOrderLevel());
}
public static String getItemID(){
return itemID;
}
public static String getItemDesc() {
return itemDesc;
}
public static double getPrice() {
return price;
}
public double setPrice(double price) {
this.price = price;
return price;
}
public static int getQuantity() {
return quantity;
}
public int setQuantity(int quantity) {
this.quantity = quantity;
return quantity;
}
public static int getReOrderLevel(){
return reOrderLevel;
}
public int setReOrderLevel(int reOrderLevel){
this.reOrderLevel = reOrderLevel;
return reOrderLevel;
}
}
The output I get is:
STOCK ITEMS
ItemID Item Description Price Quantity Re Order
P129 i5 500HQ Processor 127.0 10 45
P129 i5 500HQ Processor 127.0 10 45
P129 i5 500HQ Processor 127.0 10 45
BUILD SUCCESSFUL (total time: 0 seconds)

As a rule, never set static fields in a constructor. It is almost certainly a bug. IMHO, this should be a compiler error but it's not.
In this case, you are expecting each instance of StockItem to be different, however by making the fields static you are ensuring there is only one copy, only one value for those fields. I suggest you make them instance fields.
public class StockItem {
private final String itemID; // Five alpha-numeric characters
private final String itemDesc; // Item description
private double price; // Item price in pounds sterling
private int quantity; // Quantity in stock
private int reOrderLevel; // Level at which to re-order
public StockItem(String itemID, String itemDesc, double price, int quantity, int reOrderLevel) {
this.itemID = itemID;
this.itemDesc = itemDesc;
this.price = price;
this.quantity = quantity;
this.reOrderLevel = reOrderLevel;
}

It's been a little while since I've used Java but it seems weird that in your addItem() method in your StockList class that you pass in a parameter 'item' but then never use it inside the method.
Why are you trying to "get" all of the properties of the stock item to add when you are passing them in to the function as a StockItem object?

Guess something is wrong here:
#Override
public void addItem(StockItem item) {
StockItem aItem = new StockItem(StockItem.getItemID(),
StockItem.getItemDesc(), StockItem.getPrice(), StockItem.getQuantity(), StockItem.getReOrderLevel());
StockItems.add(counter, aItem);
counter++;
}
All those getters are static methods. It does not make sense to me since I would think you want to get instance variables belonging to different objects. You must have initialiazed the StockItem class instance variables with the values printed out, otherwise I do not think your code would even compile.
Anyway why not adding the item passed as a parameter directly to the stock list?
Like so:
#Override
public void addItem(StockItem item) {
StockItems.add(counter, item);
counter++;
}

Creating a invoiceline class

Invoice Line class represent some line in the invoice that records the item sold and the quantity.An invoice line should include the following attributes: item Sold: this is an instance variable of type Item.
quantity: an integer that represents the number of units being purchased of this item.Include the following methods in your Invoice Line class: A constructor that takes the following four input parameters: item number, item description, item price, and quantity. The constructor then uses the input parameters to initialize the two instance variables to getters and setters methods for the two instance variable so get Line Total: a method to calculate and return the total price for this line (i.e., quantity * item’s price). to String method that returns a one-line description of the invoice line. The description should include item’s details, quantity purchased, and total cost of the line.
*** I am trying to get the other variables from a different class called item class to the invoiceline class, but I cannot seem to do it. So far I have this. Any Help!?
public class InvoiceLine {
//Instance Variables
private Item itemSold;
private int quantity;
// Constructors
public InvoiceLine(){}
public InvoiceLine(String itemSold, int quantity){
itemSold = new Item(itemSold);
this.quantity = quantity;
}
//Getters
public Item getItemSold(){
return itemSold;
}
public int getQuantity(){
return quantity;
}
//Setters
private void setItemSold(Item itemSold){
this.itemSold = itemSold;
}
private void setQuantity(int quantity){
this.quantity = quantity;
}
// Methods
public double getLineTotal(double total){
total = itemPrice * quantity;
return total;
}
public String toString(){
String invoiceLine = "";
invoiceLine = (itemSold + " brought "+ quantity + ", which the total cost is "+ total);
return invoiceLine;
}
}
Item Class:
public class Item {
//Instance Variables
private int itemNum;
private String itemDescription;
private double itemPrice;
//Constructors
public Item(){}
//Initialize the three variables
public Item(int itemN, String itemDesc, double itemPri){
this.itemNum = itemN;
this.itemDescription = itemDesc;
this.itemPrice = itemPri;
}
public Item(String itemDesc){
this.itemDescription = itemDesc;
this.itemNum = 0;
this.itemPrice = 0;
}
//Getters
public int getItemNum(){
return itemNum;
}
public String getItemDescription(){
return itemDescription;
}
public double getItemPrice(){
return itemPrice;
}
//Setters
private void setItemNum(int itemN){
itemNum = itemN;
}
private void setItemDescription(String itemDesc){
itemDescription = itemDesc;
}
private void setItemPrice(double itemPri){
itemPrice = itemPri;
}
// toString method output description of the item
public String toString(){
String itemDetail = "";
itemDetail = ("Item number is "+ itemNum + ", which is a "+ itemDescription + " and price is " + itemPrice);
return itemDetail;
}
}

Try to change itemSold = new Item(itemSold); to this.itemSold = new Item(itemSold);
In this case the parameter itemSold is shadowing the attribute itemSold, so to access the attribute you have to prefix it with this.

Getters and Setters returning null

I'm trying to write a very simple program that produces an invoice for an item purchased.
I have a driver class with my setters and getters, and my object class which is supposed to call them. However, when I print out the invoice, it just produces null responses for everything.
Here is my driver class:
public class Invoice {
private String partNumber; //part number of item
private String description; //description of item
private int quantity; //quantity being purchased
private double itemPrice; //price of item
//constructor
public Invoice(String partNumber, String description, int quantity, double itemPrice) {
partNumber = partNumber;
description = description;
if (quantity < 0) {
quantity = 0;
}
if (itemPrice < 0.0) {
itemPrice = 0.0;
}
}
public void setPartNumber(String number) {
partNumber = number; //store the partNumber
}
public void setDescription(String description) {
description = description;//store the description
}
public void setQuantity(int quantity) {
quantity = quantity;//store the quantity
}
public void setItemPrice(double price) {
itemPrice = price;//store the itemPrice
}
public String getPartNumber() {
return partNumber;//retrieve the partNumber
}
public String getDescription() {
return description;//retrieve the description
}
public int getQuantity() {
return quantity;//retrieve the quantity
}
public double getItemPrice() {
return itemPrice;//retrieve the itemPrice
}
//get price for item purchased.
public double getInvoiceAmount(double amount) {
amount = itemPrice * quantity;
if (amount < 0) {
amount = 0.0;
}
return amount;
}
}
And here is my object class:
public class InvoiceTest {
public static void main(String[] args) {
Invoice invoice1 = new Invoice ("0001", "Hammer: used to hit nails.", 1, 10.0);
System.out.println("Item purchased: " + invoice1.getPartNumber() +
"\n Description: " + invoice1.getDescription() +
"\n Amount:" + invoice1.getQuantity() +
"\n price: " + invoice1.getQuantity());
System.out.println();
System.out.println("Total price: " + invoice1.getInvoiceAmount(amount));
}
}

You forgot to assign the variables to the fields in constructor. Use this keyword to refer to the class fields:
public Invoice(String partNumber, String description, int quantity, double itemPrice) {
//here's an example
//partNumber = partNumber
this.partNumber = partNumber;
//description = description;
this.description = description;
//similar for other assignments inside the constructor...
}
You must also do this in your setters as well:
public void setPartNumber(String partNumber) {
this.partNumber = partNumber; //store the partNumber
}

Your class's member fields are not being initialized as you intended, because of this:
public Invoice(String partNumber, String description, int quantity, double itemPrice)
{
partNumber = partNumber;
Here, partNumber refers to the function argument, not the member field. To set the member field, use this.partNumber = partNumber.

Your setters are not setting the values into the object instance, you need to make changes like below
public Invoice(String partNumber, String description, int quantity,
double itemPrice) {
this.partNumber = partNumber;
this.description = description;
this.quantity = quantity;
if (this.quantity < 0) {
this.quantity = 0;
}
this.itemPrice = itemPrice;
if (this.itemPrice < 0.0) {
this.itemPrice = 0.0;
}
}
public void setPartNumber(String number) {
this.partNumber = number; //store the partNumber
}
public void setDescription(String description) {
this.description = description;//store the description
}
public void setQuantity(int quantity) {
this.quantity = quantity;//store the quantity
}
public void setItemPrice(double price) {
this.itemPrice = price;//store the itemPrice
}

Point Of Sales - Stuck on arrays

Basically I have multiple classes and I'm trying to get an array of LineItem for each Item that a customer purchases. LineItem includes the UPC, Description, Price, Quantity, SubTotal and Discount which is all stored in a seperate class. I'm trying to get it that when you use the method addItemToSaleList it will add to the array. I need to use an array and not an array list, so I have to copy over the array to a temp array, and then recreate a new array adding to the number the array can store and then recopying it over. I'm stuck getting the array to generate. Below is the code I have
public class Product {
private double price;
private String description;
private String ProductCode;
private DiscountStrategy discoutStrategy;
public Product(double price, String description, String ProductCode, DiscountStrategy discoutStrategy) {
this.price = price;
this.description = description;
this.ProductCode = ProductCode;
this.discoutStrategy = discoutStrategy;
}
public double getPrice() {
return price;
}
public void setPrice(double price) {
this.price = price;
}
public String getDescription() {
return description;
}
public void setDescription(String description) {
this.description = description;
}
public String getProductCode() {
return ProductCode;
}
public void setProductCode(String ProductCode) {
this.ProductCode = ProductCode;
}
public DiscountStrategy getDiscountStrategy() {
return discoutStrategy;
}
public void setDiscoutStrategy(DiscountStrategy discoutStrategy) {
this.discoutStrategy = discoutStrategy;
}
}
public class LineItem {
private Product product;
private double quantity;
public LineItem(Product product, double quantity) {
this.product = product;
this.quantity = quantity;
}
//Calculates the Discount Amount whether or not it's a percentage or dollar
//off
public double getDiscountAmount () {
return product.getDiscountStrategy().getDiscount(product.getPrice(), quantity);
}
//Calculates the Subtotal, gets the quantity from the DiscountStrategy and then
//the price from the product
public double getSubTotal() {
return quantity * product.getPrice();
}
public Product getProduct() {
return product;
}
public void setProduct(Product product) {
this.product = product;
}
public double getQuantity() {
return quantity;
}
public void setQuantity(double quantity) {
this.quantity = quantity;
}
public class Receipt {
private LineItem[] lineItem = new LineItem[0];
public Receipt(LineItem[] lineItem) {
this.lineItem = lineItem;
}
public void addProductToTotalSale(LineItem li) {
addItemToSaleList();
}
public void addItemToSaleList() {
LineItem[] tempItemList = new LineItem[lineItem.length + 1];
for (int i = 0; i < tempItemList.length; i++) {
tempItemList[i] = lineItem[i];
}
lineItem = new LineItem[tempItemList.length];
for (int j = 0; j < lineItem.length; j++) {
lineItem[j] = tempItemList[j];
}
}
public LineItem[] getLineItem() {
return lineItem;
}

I would remove addItemToSaleList() and implement addProductToTotalSale(LineItem) like so
public void addProductToTotalSale(LineItem li) {
// Allocate the memory.
LineItem[] tempLineItem = new LineItem[1 + lineItem.length];
// Copy the array.
if (lineItem.length > 0) {
System.arraycopy(lineItem, 0, tempLineItem, 0, lineItem.length);
}
// add the new item to the new slot.
tempLineItem[lineItem.length] = li;
// update the internal array reference.
lineItem = tempLineItem;
}
Next, you should protect your constructor from null;
public Receipt(LineItem[] lineItem) {
// Try and protect from bad calls, removes need to check for nulls in
// add (addProductToTotalSale) routine.
if (lineItem != null) {
this.lineItem = lineItem;
}
}
Because you provide a default 0 sized array your code appears to be safe to continue to include the default constructor. But, you might consider making your Receipt class immutable.

I'm not sure why you are making two new arrays. You only need one...
public void addProductToTotalSale(LineItem li) {
addItemToSaleList();
lineItem[lineItem.length-1] = li;
}
public void addItemToSaleList() {
LineItem[] tempItemList = new LineItem[lineItem.length + 1];
for (int i = 0; i < tempItemList.length; i++) {
tempItemList[i] = lineItem[i];
}
lineItem = tempItemList;
}

Array sorting printing and summing

What would be the simplest method to print this array broken down into each mobile phone as a product number, name department etc, and then re print the same information sorted by product name. I have tried a couple different methods and am already passed the turn in date for the assignment but still need to figure it out for upcoming assignment this weekend. When I try to implement the comparator on MobilePhone class it forces me to make it abstract or use #override but I can't figure out where or what to override to make it work because the abstract class causes a multitude of other problems.
package InventoryPro2;
import java.util.*;
class MobilePhone {
private double productNumber; // Variables
private String name;
private String department;
private double unitsInStock;
private double unitPrice;
public MobilePhone() {
this(0.0, "", "", 0.0, 0.0);
}
public MobilePhone(double productNumber, String name, String department,
double unitsInStock, double unitPrice) { //assign variables
this.productNumber = productNumber;
this.name = name;
this.department = department;
this.unitsInStock = unitsInStock;
this.unitPrice = unitPrice;
}
public double getproductNumber() { // retrieve values
return productNumber;
}
public String getname() {
return name;
}
public String getdepartment() {
return department;
}
public double getunitPrice() {
return unitPrice;
}
public double getunitsInStock() {
return unitsInStock;
}
public void setproductNumber(double productNumber) {
this.productNumber = productNumber;
}
public void setname(String name) {
this.name = name;
}
public void setdepartment(String department) {
this.department = department;
}
public void setunitPrice(double unitPrice) {
this.unitPrice = unitPrice;
}
public void setunitsInStock(double unitsInStock) {
this.unitsInStock = unitsInStock;
}
public double gettotalInv() {
return getunitPrice() * getunitsInStock();
}
}
public class InventoryPro2 {
MobilePhone mobilephone = new MobilePhone();
public static void main(String args[]) {
System.out.println("Mobile Phone Inventory Program");
System.out.println();//skips a line
MobilePhone[] phones = new MobilePhone[5];
phones[0] = new MobilePhone();
phones[0].setproductNumber(1);
phones[0].setname("Motorola");
phones[0].setdepartment("Electronics");
phones[0].setunitPrice(150.10);
phones[0].setunitsInStock(98);
phones[1] = new MobilePhone();
phones[1].setproductNumber(2);
phones[1].setname("Samsung");
phones[1].setdepartment("Electronics");
phones[1].setunitPrice(199.99);
phones[1].setunitsInStock(650);
phones[2] = new MobilePhone();
phones[2].setproductNumber(3);
phones[2].setname("Nokia");
phones[2].setdepartment("Electronics");
phones[2].setunitPrice(200.25);
phones[2].setunitsInStock(125);
phones[3] = new MobilePhone();
phones[3].setproductNumber(4);
phones[3].setname("LG");
phones[3].setdepartment("Electronics");
phones[3].setunitPrice(100.05);
phones[3].setunitsInStock(200);
phones[4] = new MobilePhone();
phones[4].setproductNumber(5);
phones[4].setname("IPhone");
phones[4].setdepartment("Electronics");
phones[4].setunitPrice(299.99);
phones[4].setunitsInStock(150);
System.out.println("Order of inventory before sorting:");
System.out.println();
}
}
(Also, what is the best way to take just one piece of information out of each part of the array such as the totalInv and total all of those numbers to print?) Do I have unnecessary code here or have I done everything right thus far? I have to say that learning this coding language in an online format has not been a very enjoyable experience thus far..

Here is how to sort by name
import java.util.Arrays;
import java.util.Comparator;
public class AppInventoryPro2 {
public static void main(String... args) {
System.out.println("Mobile Phone Inventory Program");
System.out.println();// skips a line
MobilePhone[] phones = new MobilePhone[5];
phones[0] = new MobilePhone();
phones[0].setproductNumber(1);
phones[0].setname("Motorola");
phones[0].setdepartment("Electronics");
phones[0].setunitPrice(150.10);
phones[0].setunitsInStock(98);
phones[1] = new MobilePhone();
phones[1].setproductNumber(2);
phones[1].setname("Samsung");
phones[1].setdepartment("Electronics");
phones[1].setunitPrice(199.99);
phones[1].setunitsInStock(650);
phones[2] = new MobilePhone();
phones[2].setproductNumber(3);
phones[2].setname("Nokia");
phones[2].setdepartment("Electronics");
phones[2].setunitPrice(200.25);
phones[2].setunitsInStock(125);
phones[3] = new MobilePhone();
phones[3].setproductNumber(4);
phones[3].setname("LG");
phones[3].setdepartment("Electronics");
phones[3].setunitPrice(100.05);
phones[3].setunitsInStock(200);
phones[4] = new MobilePhone();
phones[4].setproductNumber(5);
phones[4].setname("IPhone");
phones[4].setdepartment("Electronics");
phones[4].setunitPrice(299.99);
phones[4].setunitsInStock(150);
System.out.println("Order of inventory before sorting:");
System.out.println(Arrays.toString(phones));
Arrays.sort(phones, new Comparator<MobilePhone>() {
#Override
public int compare(MobilePhone mp1, MobilePhone mp2) {
return mp1.getname().compareTo(mp2.getname());
}
});
System.out.println("Order of inventory after sorting by name:");
System.out.println(Arrays.toString(phones));
}
}
class MobilePhone {
private double productNumber; // Variables
private String name;
private String department;
private double unitsInStock;
private double unitPrice;
public MobilePhone() {
this(0.0, "", "", 0.0, 0.0);
}
public MobilePhone(double productNumber, String name, String department,
double unitsInStock, double unitPrice) { // assign variables
this.productNumber = productNumber;
this.name = name;
this.department = department;
this.unitsInStock = unitsInStock;
this.unitPrice = unitPrice;
}
public double getproductNumber() { // retrieve values
return productNumber;
}
public String getname() {
return name;
}
public String getdepartment() {
return department;
}
public double getunitPrice() {
return unitPrice;
}
public double getunitsInStock() {
return unitsInStock;
}
public void setproductNumber(double productNumber) {
this.productNumber = productNumber;
}
public void setname(String name) {
this.name = name;
}
public void setdepartment(String department) {
this.department = department;
}
public void setunitPrice(double unitPrice) {
this.unitPrice = unitPrice;
}
public void setunitsInStock(double unitsInStock) {
this.unitsInStock = unitsInStock;
}
public double gettotalInv() {
return getunitPrice() * getunitsInStock();
}
#Override
public String toString() {
return "MobilePhone [productNumber=" + productNumber + ", name=" + name
+ ", department=" + department + ", unitsInStock="
+ unitsInStock + ", unitPrice=" + unitPrice + "]";
}
}

1 - To print content of MobilePhone class: Override default toString method like this:
#Override
public String toString() {
return "MobilePhone [productNumber=" + productNumber +
", name=" + name + ']'; // add more info if needed
}
2 - To allow sorting by name: Have MobilePhone class implement Comparable interface like
this:
class MobilePhone implements Comparable {
...
#Override
public int compareTo(Object o) {
MobilePhone m = (MobilePhone) o;
return (this.name.compareTo(o.name));
}
}
EDIT: To print your array of MobilePhone object you can do:
System.out.printf("Phones: %s%n", Arrays.toString(phones));