Adding to separate ArrayLists into a main ArrayList

Question

I am developing a simple POS program. Which I have a couple loops to add the part information to a list (invoiceList), then all the parts ordered under another list (invoiceListMain) and then all the invoices ordered into a main list (invoiceLogList). So essentially I have List within List within List.

This works when I output the whole list in a print statement. But I need to be able to unpack the list.

[[738, [113, 5.0, 43.45], [248, 2.0, 12.78]], [459, [248, 10.0, 63.9], [113, 1.0, 8.69]]]

I get this error

ArrayListDemo.java:136: error: incompatible types: String cannot be converted to ArrayList for(ArrayList line : invoiceLogList)

when I do:

for(int i=0; i < invoiceLogList.size(); i++)
         {
           for(ArrayList<String> line : invoiceLogList)
           {
              System.out.print(" \n" + line.get(0));
           }

         }

Before negative ratings, please leave a reason why.

From researching, I think it has to do with how I had to compile all my list within list within list.

invoiceLogList.add(invoiceListMain.toString());

I had to add .toString() in order to get this to work. So my guess is I can't unpack this as an Array because it is no longer an array? It's a list? I'm not 100% sure.

Does anyone have advice on a better way or how to unpack the data within?

import java.util.ArrayList;
import java.util.Scanner;
import java.util.Random;


public class ArrayListDemo {

   public static void main(String[]args){

      //Part 1
      ArrayList<String> part1 = new ArrayList<String>();

      part1.add("06011");     
      part1.add("Castrol EDGE 0W20 Motor Oil - 1 qt");
      part1.add("9.49");

      //Part 2
      ArrayList<String> part2 = new ArrayList<String>();

      part2.add("248");     
      part2.add("Castrol EDGE 5W30 Motor Oil - 1 qt");
      part2.add("6.39");

      //Part 3   
      ArrayList<String> part3 = new ArrayList<String>();

      part3.add("03050");
      part3.add("Castrol Hypuron 10W30 Motor Oil - 1 gal");
      part3.add("6.39");

      //Part 4
      ArrayList<String> part4 = new ArrayList<String>();

      part4.add("113");
      part4.add("Castrol Pyroplex Protection ES Multi-Purpose Grease - 14 oz");
      part4.add("8.69");

      //Part 5
      ArrayList<String> part5 = new ArrayList<String>();

      part5.add("020");
      part5.add("Castrol GTZ ULTRACLEAN 5W20 Motor Oil - 6 gal");
      part5.add("69.99");


      //adding parts to main Part List
      ArrayList<ArrayList<String>> mainPartList = new ArrayList<ArrayList<String>>();

      mainPartList.add(part1);     
      mainPartList.add(part2);
      mainPartList.add(part3);
      mainPartList.add(part4);
      mainPartList.add(part5);


//-----INVOICE INPUT----------------------------------------------------------------------------

      //create a new scanner
      Scanner input = new Scanner(System.in);

      //Invoice Input
      String a = "";
      String invoiceNumber = "";
      String p = "";
      double q = 0.0;
      double partPrice = 0.0;
      double partSum = 0.0;
      String partNum = "";
      String partDescrip = "";
      String c = "";

      //Invoice Array

      ArrayList<String> invoiceLogList = new ArrayList<>();//Stores all invoices created
         do{//loop to create invoice

            ArrayList<String> invoiceListMain = new ArrayList<>();//stores individual invoices

            Random generator = new Random();//creates random invoice number     
            int sequence = generator.nextInt(1000);
            invoiceListMain.add(String.format("%03d", sequence));//invoice number
            System.out.print("Invoice #: " + sequence);

            do{//loop to add parts to invoice

               ArrayList<String> invoiceList = new ArrayList<String>();//stores part#, qty, sumTotal

               System.out.print("\n\nPart Number: ");
               p = input.next();

               //fetch part info from array mainPartList
               for(ArrayList<String> part : mainPartList)
               {
                  if(part.contains(p))
                  { 
                    for (int i = 0; i < 1; i++)
                       partNum = part.get(0);   
                       partDescrip = part.get(1);
                       invoiceList.add(partNum);//add part# to list
                       System.out.print("\t" + partNum + " - " + partDescrip);
                       partPrice = Double.parseDouble(part.get(2));//grabs price of part in list                   
                  }
               }

               System.out.print("\nQuantity: ");
               q = input.nextDouble(); //asks quantity sold
               invoiceList.add(Double.toString(q));//add quantity to list

               partSum = partPrice * q;
               invoiceList.add(Double.toString(partSum));//add part sum to list
               System.out.printf("\t $%.2f",partSum);

               System.out.print("\n\n---Add to cart?: ");
               c = input.next();

               invoiceListMain.add(invoiceList.toString());//adding part order to mainList

               }while(c.equalsIgnoreCase("Y")); 


             //Create Invoice Loop
             System.out.print("\n\nCreate a new Invoice? ");
             a = input.next();

             invoiceLogList.add(invoiceListMain.toString());

             }while(a.equalsIgnoreCase("Y"));



          //Print all invoices
          for(int i=0; i < invoiceLogList.size(); i++)
          {
            for(ArrayList<String> line : invoiceLogList)
            {
              System.out.print(" \n" + line.get(0));
            }

          }
   }
}

when you say unpack? do you mean change the List<List<List<String>>> to a List<String> ? — Ousmane D.
– Ousmane D., Commented Apr 29, 2018 at 14:21
invoiceListMain - Arraylist holding all the products ordered my the user — Sam
– Sam, Commented Apr 29, 2018 at 14:25
Yes, your problem is the invocation of toString(). Why did you need to do that? — Vytautas
– Vytautas, Commented Apr 29, 2018 at 14:28
@Sam Right, don't use two, three separate lists to maintain related data, instead create a class with the required properties, overriding toString, then you can have a List<SomeType> where SomeType is the class name. — Ousmane D.
– Ousmane D., Commented Apr 29, 2018 at 14:29

Taha Kerrouzi · Accepted Answer · 2018-04-29 15:05:43Z

1

i try that example and that what i get maybe that what u want !

ArrayList<ArrayList<ArrayList<String>>> invoiceLogList= new ArrayList<ArrayList<ArrayList<String>>> ();
    ArrayList<ArrayList<String>> invoiceListMain= new ArrayList<ArrayList<String>>();
    ArrayList<String> c = new ArrayList<String>();
    c.add("13");
    c.add("50");
    c.add("43.45");
ArrayList<String> d = new ArrayList<String>();
d.add("728");
invoiceListMain.add(d);
invoiceListMain.add(c);
invoiceLogList.add(invoiceListMain);

  for(int i=0; i < invoiceLogList.size(); i++)
         {
           for(ArrayList<ArrayList<String>> line :invoiceLogList)
           {
              System.out.print(" \n" + line.get(0));
           }

         }

Output:

[728]
BUILD SUCCESSFUL (total time: 0 seconds)

answered Apr 29, 2018 at 15:05

Taha Kerrouzi

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1 Comment

Sam Over a year ago

well damn, there's my issue. I think with some tweeking this will help all my problems. I didn't know that I needed all the ArrayList<ArrayList<ArrayList

Nick Mowen · Accepted Answer · 2018-04-29 14:36:20Z

0

It's because you are accessing the same list in both loop headers, I believe making this correction should fix the issue:

for(int i=0; i < invoiceLogList.size(); i++)
         {
           for(ArrayList<String> line : invoiceLogList.get(i))
           {
              System.out.print(" \n" + line.get(0));
           }

         }

answered Apr 29, 2018 at 14:36

Nick Mowen

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1 Comment

Sam Over a year ago

I get this error: for-each not applicable to expression type

Ofer Skulsky · Accepted Answer · 2018-04-29 14:40:59Z

0

If you look at your print out,
you can see that 738 and 459 are one level too high.

Here is a break down by depth:
list with 2 elements
the 1st contains a list of 3 elements that are:
* a string 738
* a List of Strings [113, 5.0, 43.45]
* a List of Strings [248, 2.0, 12.78]

This was suppose to be a list of lists (from your story).
this is what the exception is telling you.

answered Apr 29, 2018 at 14:40

Ofer Skulsky

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1 Comment

Sam Over a year ago

It is a list of lists if I had entered more than 1 invoice. 738 is the invoice number which contains the parts numbers ordered which is [113, 5, 43.45][248, 2, 12.78]

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