Java arraylist add the qty
===

I am a java newbie and I am having an issue with comparing the properties of myProduct.setRefno(product.getRefno()), imported from another class along description, price and qty. In written terms I need to be able to key in a refno and if the ref no exists in the basket container then add only the qty rather than all the item details:

Currently program works as follows:

ref1 description1 price1 1(qty)
ref2 description2 price2 1(qty)
ref1 description1 price1 1(qty)

However I would like it as:

ref1 description1 price1 2(qty)
ref2 description2 price2 1(qty)

Therefore it should be if it is the same refno then add only the qty. Pls help!!!

 1. List item

         public class Zapper 
	      {
	
		public static void main(String[] args) throws ItemException
		{
			
			System.out.println("\n\nThis is Purchases\n\n");
			
			
			
			Products stock=new Products();// Define Variable 
			Products basket=new Products();// Define Variable 
			Purchase product;
			String refno;
			int offer;
			int count;
			int grandtotal;
			
			

			
			
			char option;//char variable option
			
			boolean finished=false;//variable "boolean" set 
			
			while (!finished)
			{
				
				try
				{
					option=Console.askOption("\n A)dd P)rint R)emove Q)uit");
					stock.open("stock.lin");
					switch (option) 
					{	
						case 'A': 
							product= new Purchase();//Constructing new "item" variable
							refno= Console.askString("Enter Ref No:..");
							product=(Purchase)stock.find(refno);//cast operator 
							if ( product == null)
								System.out.println("Cannot find Ref No");
							
							else
							{
							    product.print("");
							    Purchase myProduct = new Purchase();
							    myProduct.setRefno(product.getRefno());
							    myProduct.setDescription(product.getDescription());
							    myProduct.setPrice(product.getPrice());
							    myProduct.setQty(1);
							    myProduct.setOffer(product.getOffer());
							    basket.add(myProduct);//add the value of item into Container stock
							   	    
							    
							}
							break;//end of case statement Add
							
						case 'R': 
							refno= Console.askString("Enter Ref No:..");
							Product myProduct = new Product();
							myProduct=(Purchase)basket.find(refno);//cast operator
							myProduct.setQty(1);
							if ( myProduct == null)
								System.out.println("Cannot find Ref No");
							
							else
							{
								
								basket.remove(myProduct);
								basket.print("");	
							}
							break;//end of case statement Find
							
						case 'P': 
							
							basket.print("\nYou have purchased...");
							
							
							break;//end of case statement Print
							
												
						case 'Q': 
							finished=true;
							
							break;//end of case statement "Q" 
						
						case '\0':/*Do Nothing*/
							break;//end of case statement "Do Nothing"
							
						default:	
							System.out.println("Error: Invalid Option ");
							break;//end of case statement default
					}//end of switch
				
				}//end of try
				
				catch (ItemException e)
				{
					System.out.println(e.getMessage());
				}
				
				catch (IOException e)
				{
					System.out.println(e.getMessage());
				}
				
				catch (Exception e)
				{
					System.out.println(e.getMessage());
				}
				
			}//end of whiled
			
			
			
			System.out.println("\n\nPurchases Finished \n\n");
			

		}

	}

