Java Inventory

[Os Stewart]

I realy need some help. My teacher said,"Inventory_Program has myInventory instantiated as an array and then is instantiated again as a non-array object. The next 2 errors on that class are related to the first error. (3 errors)." What does this mean? I will be honest, I just want to get this class done. I haven't had problems in any class but this one. I am two weeks from craduation, and I need someone to tell me what I am doing wrong. Please?

/*
* To change this license header, choose License Headers in Project Properties.
* To change this template file, choose Tools | Templates
* and open the template in the editor.
*/
package inventory_program;
import java.util.Arrays;
import java.util.Scanner;
/**
*
* @author Ofelia G. S. Stewart
*/
public class Inventory_Program {
public static void main(String[] args) {
Boolean run = true;
Scanner input = new Scanner(System.in);
DVD_Inventory[] myInventory = new DVD_Inventory[5];
final String cmd = "Enter 'Y' or 'N'";
System.out.printf("%s%n%n%n", "Welcome! ");
System.out.println("Item Name | # | Stock | Price | Value");
System.out.println("---------------------------------------");
do {
for (int i = 0; i < 5; i++) {
myInventory = new DVD_Inventory();
}
for (int i = 0; i < myInventory.length; i++) {
myInventory.runInventory(i);
myInventory.displayInventory();
System.out.printf("Total value of DVD inventory is: $%.2f%n%n", calcValue(myInventory));
System.out.printf("%s%n%s%n", "Sort this list?", cmd);
String choice1 = input.next();
if (choice1.equalsIgnoreCase("y")) {
Arrays.sort(myInventory);
System.out.println("Item Name | # | Stock | Price | Value");
System.out.println("---------------------------------------");
for (DVD_Inventory myInventory2 : myInventory) {
myInventory2.displayInventory();
}
}
System.out.printf("%s%n%s%n", "Would you like to continue?", cmd);
String choice2 = input.next();
if (choice2.equalsIgnoreCase("n")) {
run = false;
}
System.out.println();
} while (run);
System.out.printf("%s%n", "Thank you!");
}
private static double calcValue(DVD_Inventory[] values) {
double totalValue=0;
for(DVD_Inventory oldValues: values){
totalValue+=oldValues.getValue();
}
return totalValue;
}
} 

/*
* To change this license header, choose License Headers in Project Properties.
* To change this template file, choose Tools | Templates
* and open the template in the editor.
*/
package inventory_program;
import java.util.Random;
/**
*
* @author Ofelia G. S. Stewart
*/
class DVD_Inventory implements Comparable<DVD_Inventory> {
private String itemName;
private int itemNumber;
private int itemStock;
private double itemPrice;
private double itemValue;
Random rnd = new Random();
public DVD_Inventory() {
itemName = "";
itemNumber = 0;
itemStock = 0;
itemPrice = 0;
itemValue = 0;
}
public void runInventory(int row) {
setName();
setNumber(row);
setStock();
setPrice();
setValue();
}
public void displayInventory() {
System.out.printf("%9s | %d | %5d | $%.2f | $%,.2f%n", itemName, itemNumber, itemStock, itemPrice, itemValue);
System.out.println("---------------------------------------");
}
public String getName() {
return itemName;
}
public int getNumber(){
return itemNumber;
}
public int getStock(){
return itemStock;
}
public double getPrice(){
return itemPrice;
}
public double getValue() {
return itemValue;
}
private void setName() {
final String AB = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
int len = 5 + rnd.nextInt(5);
StringBuilder sb = new StringBuilder(len);
for (int i = 0; i < len; i++) {
sb.append(AB.charAt(rnd.nextInt(AB.length())));
}
itemName = sb.toString();
}
private void setNumber(int row) {
itemNumber = row + 1;
}
private void setStock() {
itemStock = 1 + rnd.nextInt(500);
}
private void setPrice() {
itemPrice = 10 + 10 * rnd.nextDouble();
}
private void setValue() {
itemValue = itemStock * itemPrice;
}
@Override
public int compareTo(DVD_Inventory o) {
int result = itemName.compareToIgnoreCase(o.itemName);
return result;
}
} 

[Bear Bibeault]

Please cut/past the exact text of the error messages including line numbers.

[Jeanne Boyarsky]

I think your teacher is trying to point out that myInventory = new DVD_Inventory(); doesn't compile because myInventory is an array.

[Os Stewart]

Lines 30, 35, 36, The while statement on line 57 says "Empty statement after while", Lines 59 and 61 all on the Inventory_Program.java.

@Jeanne Boyarsky If it's an array, do I get rid of myInventory = new DVD_Inventory(); ??? I don't really get this like I said, I'm sorry, It's embarrassing really. I have read and read, and I can't get this. It's this type of class I wish I didn't do online. :-(

[Os Stewart]

When I Debug on Netbean this is what I get:

debug:
Welcome!


Item Name | # | Stock | Price | Value
---------------------------------------

[Jeanne Boyarsky]

 

Ofelia Stewart wrote:@Jeanne Boyarsky If it's an array, do I get rid of myInventory = new DVD_Inventory(); ??? I don't really get this like I said, I'm sorry, It's embarrassing really. I have read and read, and I can't get this. It's this type of class I wish I didn't do online. :-(

What is the purpose of that line? Is it to create a single DVD? To create a single DVD and add it to the array? Something else? Try to explain it in English first.

[Os Stewart]

This is what I was asked to do for this assignment.

Modify the Inventory Program so the application can handle multiple
items. Use an array to store the items. The output should display the
information one product at a time, including the item number, the name
of the product, the number of units in stock, the price of each unit, and
the value of the inventory of that product. In addition, the output should
display the value of the entire inventory.
Create a method to calculate the value of the entire inventory.
Create another method to sort the array items by the name of the
product.

I need the items stored in the array, and I need to be able to output information ones at a time. At the end of the program, I need to output and display the value of all/ the entire, inventory value. Does this help? The program I compiled last week is what I used to modify to create what I have created here, this week.

[Scott Winterbourne]

On line 21 of your Inventory_Program class you initialize the myInventory variable as an Array of DVD_Inventory objects. On line 30 you then reassign the myInventory variable to a single DVD_Inventory object thus losing the Array.

DVD_Inventory[] myInventory = new DVD_Inventory[5];
// Initialize myInventory as an Array of DVD_Inventory objects
final String cmd = "Enter 'Y' or 'N'";
System.out.printf("%s%n%n%n", "Welcome! ");
System.out.println("Item Name | # | Stock | Price | Value");
System.out.println("---------------------------------------");
do {
for (int i = 0; i < 5; i++) {
myInventory = new DVD_Inventory();
/* Reassign the myInventory variable to a single
* DVD_Inventory object losing Array that was assigned to it.
*/
}

I believe this is what your teacher was talking about. I think what you might need to do is instead of assigning the new DVD_Inventory object to the variable, you want to assign the object to a location in the array like this:

for(int i = 0; i < 5; i++){
myInventory[i] = new DVD_Inventory();
/* by adding [i] to the variable name, you are assigning the
* new object to the "i" location of the array as "i" counts
* from Array location 0 to 4.
*/
}

You will also need to modify line 35 and 36 to reflect the myInventory as an Array with the square brackets [].

Hope this helps you get started on debugging the rest.

[Os Stewart]

Thank you so much! It helped straighten out some of the errors and I also found some { and} that did not belong, I have issues now with :

Lines 36 and 37 say "Can not find Symbols.

Line 61 says illegal start to expression

and Line 58 (The while statement) says "Empty statement after While"

Other than that, ! got many errors fixed. When I compile, It looks like this.

[Os Stewart]

Sorry, looks like this:

debug:
Welcome!


Item Name | # | Stock | Price | Value
---------------------------------------

[Os Stewart]

OOOPPPPssss, lol sorry, I modified lines 35 and 36 like you said! Your a super angel. I would have never ever thought of those [] brackets. I've been looking at this all day trying to get it and didn't see that! Thank you beyond words!

[Os Stewart]

Okay, so I removed the ; semicolon after the while statement and I removed a couple of other things. Now I have this last issue.

Line 61

while (run)
System.out.printf("%s%n", "Thank you!");
private static double calcValue(DVD_Inventory[] values) {
double totalValue=0;
for(DVD_Inventory oldValues: values){
totalValue+=oldValues.getValue();
}
return totalValue;
}
} 

[Os Stewart]

illegal start to expression line 61 ... sorry didn't clarify that.

Debugger console says:

Listening on javadebug
User program running
Debugger stopped on uncompilable source code.
Debugger stopped on uncompilable source code.
Debugger stopped on uncompilable source code.
Thread main stopped at Inventory_Program.java:29.

[Scott Winterbourne]

It looks like you are missing the closing curly brace } after the end of the While(run) statement.

You need a closing curly brace to close the main() method before the calcValue() method.

[Os Stewart]

Thank you, This was one of the things I fixed. This is what I am getting now. I'm having difficulty with the last part from line 63 illegal start to expression.

/*
* To change this license header, choose License Headers in Project Properties.
* To change this template file, choose Tools | Templates
* and open the template in the editor.
*/
package inventory_program;
import java.util.Arrays;
import java.util.Scanner;
/**
*
* @author Ofelia G. S. Stewart
*/
public class Inventory_Program {
public static void main(String[] args) {
Boolean run = true;
Scanner input = new Scanner(System.in);
DVD_Inventory[] myInventory = new DVD_Inventory[5];
final String cmd = "Enter 'Y' or 'N'";
System.out.printf("%s%n%n%n", "Welcome! ");
System.out.println("Item Name | # | Stock | Price | Value");
System.out.println("---------------------------------------");
for(int i = 0; i < 5; i++){
myInventory[i] = new DVD_Inventory();
/* by adding [i] to the variable name, you are assigning the
* new object to the "i" location of the array as "i" counts from
* Array location 0 to 4.
*/
}
for (int i = 0; i < myInventory.length; i++) {
myInventory[i].runInventory(i);
myInventory[i].displayInventory();
System.out.printf("Total value of DVD inventory is: $%.2f%n%n", calcValue(myInventory));
System.out.printf("%s%n%s%n", "Sort this list?", cmd);
String choice1 = input.next();
if (choice1.equalsIgnoreCase("y")) {
Arrays.sort(myInventory);
System.out.println("Item Name | # | Stock | Price | Value");
System.out.println("---------------------------------------");
for (DVD_Inventory myInventory2 : myInventory) {
myInventory2.displayInventory();
}
}
System.out.printf("%s%n%s%n", "Would you like to continue?", cmd);
String choice2 = input.next();
if (choice2.equalsIgnoreCase("n")) {
run = false;
}
System.out.println();
}
while (run){
System.out.printf("%s%n", "Thank you!"); }
public static double calcValue(DVD_Inventory[] values) {
double totalValue=0;
for(DVD_Inventory oldValues: values){
totalValue+=oldValues.getValue();
}
return totalValue;
}
} 

/*
* To change this license header, choose License Headers in Project Properties.
* To change this template file, choose Tools | Templates
* and open the template in the editor.
*/
package inventory_program;
import java.util.Random;
/**
*
* @author Ofelia G. S. Stewart
*/
class DVD_Inventory implements Comparable<DVD_Inventory> {
private String itemName;
private int itemNumber;
private int itemStock;
private double itemPrice;
private double itemValue;
Random rnd = new Random();
public DVD_Inventory() {
itemName = "";
itemNumber = 0;
itemStock = 0;
itemPrice = 0;
itemValue = 0;
}
public void runInventory(int row) {
setName();
setNumber(row);
setStock();
setPrice();
setValue();
}
public void displayInventory() {
System.out.printf("%9s | %d | %5d | $%.2f | $%,.2f%n", itemName, itemNumber, itemStock, itemPrice, itemValue);
System.out.println("---------------------------------------");
}
public String getName() {
return itemName;
}
public int getNumber(){
return itemNumber;
}
public int getStock(){
return itemStock;
}
public double getPrice(){
return itemPrice;
}
public double getValue() {
return itemValue;
}
private void setName() {
final String AB = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
int len = 5 + rnd.nextInt(5);
StringBuilder sb = new StringBuilder(len);
for (int i = 0; i < len; i++) {
sb.append(AB.charAt(rnd.nextInt(AB.length())));
}
itemName = sb.toString();
}
private void setNumber(int row) {
itemNumber = row + 1;
}
private void setStock() {
itemStock = 1 + rnd.nextInt(500);
}
private void setPrice() {
itemPrice = 10 + 10 * rnd.nextDouble();
}
private void setValue() {
itemValue = itemStock * itemPrice;
}
@Override
public int compareTo(DVD_Inventory o) {
int result = itemName.compareToIgnoreCase(o.itemName);
return result;
}
} 

This is what the compile looks like:

debug:
Welcome!


Item Name | # | Stock | Price | Value
---------------------------------------
REUMWK | 1 | 192 | $11.47 | $2,201.65
---------------------------------------
Total value of DVD inventory is: $2201.65

Sort this list?
Enter 'Y' or 'N'
y
Item Name | # | Stock | Price | Value
---------------------------------------
| 0 | 0 | $0.00 | $0.00
---------------------------------------
| 0 | 0 | $0.00 | $0.00
---------------------------------------
| 0 | 0 | $0.00 | $0.00
---------------------------------------
| 0 | 0 | $0.00 | $0.00
---------------------------------------
REUMWK | 1 | 192 | $11.47 | $2,201.65
---------------------------------------
Would you like to continue?
Enter 'Y' or 'N'
y

FYWTFC | 2 | 409 | $10.29 | $4,206.85
---------------------------------------
Total value of DVD inventory is: $6408.49

Sort this list?
Enter 'Y' or 'N'
y
Item Name | # | Stock | Price | Value
---------------------------------------
| 0 | 0 | $0.00 | $0.00
---------------------------------------
| 0 | 0 | $0.00 | $0.00
---------------------------------------
| 0 | 0 | $0.00 | $0.00
---------------------------------------
FYWTFC | 2 | 409 | $10.29 | $4,206.85
---------------------------------------
REUMWK | 1 | 192 | $11.47 | $2,201.65
---------------------------------------
Would you like to continue?
Enter 'Y' or 'N'
y

IMAIVB | 3 | 151 | $10.20 | $1,540.03
---------------------------------------
Total value of DVD inventory is: $7948.53

Sort this list?
Enter 'Y' or 'N'
y
Item Name | # | Stock | Price | Value
---------------------------------------
| 0 | 0 | $0.00 | $0.00
---------------------------------------
| 0 | 0 | $0.00 | $0.00
---------------------------------------
FYWTFC | 2 | 409 | $10.29 | $4,206.85
---------------------------------------
IMAIVB | 3 | 151 | $10.20 | $1,540.03
---------------------------------------
REUMWK | 1 | 192 | $11.47 | $2,201.65
---------------------------------------
Would you like to continue?
Enter 'Y' or 'N'
y

GHFBJDZFW | 4 | 386 | $19.67 | $7,591.73
---------------------------------------
Total value of DVD inventory is: $14000.22

Sort this list?
Enter 'Y' or 'N'
y
Item Name | # | Stock | Price | Value
---------------------------------------
| 0 | 0 | $0.00 | $0.00
---------------------------------------
| 0 | 0 | $0.00 | $0.00
---------------------------------------
FYWTFC | 2 | 409 | $10.29 | $4,206.85
---------------------------------------
GHFBJDZFW | 4 | 386 | $19.67 | $7,591.73
---------------------------------------
REUMWK | 1 | 192 | $11.47 | $2,201.65
---------------------------------------
Would you like to continue?
Enter 'Y' or 'N'
y

RBXCIKFD | 5 | 7 | $16.36 | $114.53
---------------------------------------
Total value of DVD inventory is: $11913.11

Sort this list?
Enter 'Y' or 'N'
y
Item Name | # | Stock | Price | Value
---------------------------------------
| 0 | 0 | $0.00 | $0.00
---------------------------------------
| 0 | 0 | $0.00 | $0.00
---------------------------------------
FYWTFC | 2 | 409 | $10.29 | $4,206.85
---------------------------------------
GHFBJDZFW | 4 | 386 | $19.67 | $7,591.73
---------------------------------------
RBXCIKFD | 5 | 7 | $16.36 | $114.53
---------------------------------------
Would you like to continue?
Enter 'Y' or 'N'
y

Thank you!
Thank you!
Thank you!
Thank you!
Thank you!
Thank you!
Thank you!
Thank you!
Thank you!
Thank you!
Thank you!
Thank you!
Thank you!
Thank you!
Thank you!
Thank you!
Thank you!
Thank you!
Thank you!
Thank you!
Thank you!
Thank you!
Thank you!
Thank you!
Thank you!
Thank you!
Thank you!
Thank you!
Thank you!
Thank you!
Thank you!
Thank you!


And it keeps going! ... oh man...

[Os Stewart]

The error is "Exporting non-public type through public API.".

[Scott Winterbourne]

With regards to the illegal start of expression on line 63, you need to close your main() method before declaring your calValue() method as shown below:

while (run){
System.out.printf("%s%n", "Thank you!"); }
}
/* <- close the main() method with a closing curly brace
* before declaring the calcValue() method below
*/
public static double calcValue(DVD_Inventory[] values) {
double totalValue=0;
for(DVD_Inventory oldValues: values){
totalValue+=oldValues.getValue();
}
return totalValue;
}

Right now, the compiler thinks that

public static double calcValue(DVD_Inventory[] values) {

on line 63 is supposed to be an expression rather then a method declaration because the main() method is still open.

[Scott Winterbourne]

Regarding the endless loop of "Thank you", the While loop on line 60 is an infinite loop.

while (run){
System.out.printf("%s%n", "Thank you!"); }

The "run" variable is set to True on line 20 but it is never set to false thus never breaking out of this loop. What is this loop being used for? If you only want "Thank you!" to be printed once at the very end they it does not need to be inside of a while loop.

[Os Stewart]

I know this may sound stupid... but where are you seeing this main method that I still have open? I'm still trying to find it after all this. Maybe my minds just tired of looking at this. I don't see it? I feel so dumb right now.

[Os Stewart]

I completely through out the While loop. I admit that I thought it was kind of cool since I never did that before.

[Os Stewart]

I have it compiling nicely except for the warning for calcValue on Line 63. I have a question, When I compile,it's not giving the sorted list for all five, it's only doing three in my debugger console, is this because of the issue on line 63 as well?

[Os Stewart]

Sorry this is what it looks like now.

debug:
Welcome!


Item Name | # | Stock | Price | Value
---------------------------------------
NNZUNK | 1 | 39 | $17.93 | $699.41
---------------------------------------
Total value of DVD inventory is: $699.41

Sort this list?
Enter 'Y' or 'N'
y


Item Name | # | Stock | Price | Value
---------------------------------------
| 0 | 0 | $0.00 | $0.00
---------------------------------------
| 0 | 0 | $0.00 | $0.00
---------------------------------------
| 0 | 0 | $0.00 | $0.00
---------------------------------------
| 0 | 0 | $0.00 | $0.00
---------------------------------------
NNZUNK | 1 | 39 | $17.93 | $699.41
---------------------------------------
Would you like to continue?
Enter 'Y' or 'N'
y



Thank you!
VVURM | 2 | 95 | $14.55 | $1,382.69
---------------------------------------
Total value of DVD inventory is: $2082.11

Sort this list?
Enter 'Y' or 'N'
y


Item Name | # | Stock | Price | Value
---------------------------------------
| 0 | 0 | $0.00 | $0.00
---------------------------------------
| 0 | 0 | $0.00 | $0.00
---------------------------------------
| 0 | 0 | $0.00 | $0.00
---------------------------------------
NNZUNK | 1 | 39 | $17.93 | $699.41
---------------------------------------
VVURM | 2 | 95 | $14.55 | $1,382.69
---------------------------------------
Would you like to continue?
Enter 'Y' or 'N'
y



Thank you!
ZPWMO | 3 | 385 | $12.20 | $4,695.93
---------------------------------------
Total value of DVD inventory is: $6778.04

Sort this list?
Enter 'Y' or 'N'
y


Item Name | # | Stock | Price | Value
---------------------------------------
| 0 | 0 | $0.00 | $0.00
---------------------------------------
| 0 | 0 | $0.00 | $0.00
---------------------------------------
NNZUNK | 1 | 39 | $17.93 | $699.41
---------------------------------------
VVURM | 2 | 95 | $14.55 | $1,382.69
---------------------------------------
ZPWMO | 3 | 385 | $12.20 | $4,695.93
---------------------------------------
Would you like to continue?
Enter 'Y' or 'N'
y



Thank you!
VWNBIG | 4 | 445 | $10.19 | $4,536.20
---------------------------------------
Total value of DVD inventory is: $9931.54

Sort this list?
Enter 'Y' or 'N'
y


Item Name | # | Stock | Price | Value
---------------------------------------
| 0 | 0 | $0.00 | $0.00
---------------------------------------
| 0 | 0 | $0.00 | $0.00
---------------------------------------
NNZUNK | 1 | 39 | $17.93 | $699.41
---------------------------------------
VWNBIG | 4 | 445 | $10.19 | $4,536.20
---------------------------------------
ZPWMO | 3 | 385 | $12.20 | $4,695.93
---------------------------------------
Would you like to continue?
Enter 'Y' or 'N'
y



Thank you!
EYZRDG | 5 | 130 | $15.78 | $2,051.81
---------------------------------------
Total value of DVD inventory is: $7287.42

Sort this list?
Enter 'Y' or 'N'
y


Item Name | # | Stock | Price | Value
---------------------------------------
| 0 | 0 | $0.00 | $0.00
---------------------------------------
| 0 | 0 | $0.00 | $0.00
---------------------------------------
EYZRDG | 5 | 130 | $15.78 | $2,051.81
---------------------------------------
NNZUNK | 1 | 39 | $17.93 | $699.41
---------------------------------------
VWNBIG | 4 | 445 | $10.19 | $4,536.20
---------------------------------------
Would you like to continue?
Enter 'Y' or 'N'
y

Thank you!
BUILD SUCCESSFUL (total time: 10 seconds)

[Os Stewart]

Okay, I got no errors now, but I am wondering why when it compiles the list and it's suppose to be sorted, it only gives out 3 and not all 5. I'm trying to figure out where I did this at? This is what I get as the last result.

Would you like to continue?
Enter 'Y' or 'N'
y
MKJBZDDV | 5 | 300 | $18.97 | $5,689.54
---------------------------------------
Total value of DVD inventory is: $14005.11

Sort this list?
Enter 'Y' or 'N'
y
Item Name | # | Stock | Price | Value
---------------------------------------
| 0 | 0 | $0.00 | $0.00
---------------------------------------
| 0 | 0 | $0.00 | $0.00
---------------------------------------
GUPCJO | 2 | 320 | $18.70 | $5,984.27
---------------------------------------
HFCOEE | 4 | 124 | $18.80 | $2,331.30
---------------------------------------
MKJBZDDV | 5 | 300 | $18.97 | $5,689.54
---------------------------------------
Would you like to continue?
Enter 'Y' or 'N'
y
BUILD SUCCESSFUL (total time: 48 seconds)

[Scott Winterbourne]

 

Campbell Ritchie wrote:I have had to change a lot of // comments to /* … */ type because the long lines make the code difficult to read.

Sorry Campbell, I will be more mindful of my code comments.

@Ofelia
The Arrays.sort() seems to be causing the issue. I haven't used this method so I'm not sure why it is doing what it is doing, but by commenting out that line (line 49) all 5 DVD_Inventory items print out.

[Scott Winterbourne]

Ok I think I am understanding what is going on now. Since Arrays.sort() is being called during each itteration of the loop, the order of the items in the array are being changed each time before a new item is added. When the new item gets added it will "overwrite" one of the existing items.

I'm not sure what order the output needs to be in but if you just loop through the array to output the items they will display in order of the array index. You shouldn't need to use the Arrays.sort() method unless you have a specific way you need the items sorted.