Converting from Groovy to Java (HashMap issue)

sleepyescapade

Hi there,

In our first year Computer Science course, we started off learning Groovy and recently have converted to Java. I attempted to convert a Groovy problem to Java, however I think I may not be writing the HashMaps correctly? I will post both my Groovy and Java codes for this problem. Hope somebody can help, really appreciated

Groovy:

class Checkout
{ 

// Class Variables

		static CUSTOMER = 0 // the number of recently created customers

// Fields
		
		def customer // number of customers
		def groceries = []  // list of groceries bought by customer
		def food // map, containing barcode, product name and price   

// Constructor

		     def Checkout( )
		//Create a 'Checkout' object.
	
    	       {
        		CUSTOMER++

		        this.customer = CUSTOMER
     	
        		food = [5431 : ["Milk 1L", 99], 2480: ["Flour 1KG", 265 ], 4017: ["Eggs 6PK", 180]]
     	       }



// Methods

		    def scan( barcode )
		//A method to 'scan' and record the purchase of an item identified by 'barcode'.

               {
 		    this.groceries.add(food [ barcode] ) 
               }


 
		  def printReceipt( )
		//A method to 'print' a 'receipt' of all scanned items.
      {     
      		 def subTotal  = 0
       		def total = 0
       		def discount = 100
       		def product
       		def price = 0
       		def noDiscount = 000

      printf("     Welcome!%n" )
      printf("   Customer #%-4d %n", this.customer)
      printf("  Item        Price%n")
      printf("------------  -----%n")

 		for ( item in this.groceries )

           { 
             
             product = item.get(0)
             price = item.get(1)
             subTotal = subTotal + price

              printf( "%-9s     %2d.%02d %n", product, price.intdiv(100), price % 100  )

           }

      printf("------------  -----%n")
      printf("SUB-TOTAL     %2d.%02d %n", subTotal.intdiv(100), subTotal % 100)
		    
	      if ( isFactor( 7, this.customer ) ) 
       {
          printf("Lucky-7      -%2d.%02d %n", discount.intdiv(100), discount % 100) 
  	      if  ( subTotal < discount )
                total = 0.00
      	else 
                total = subTotal - discount
       }

        else
 
       {
             printf("Lucky-7      -%2d %02d %n", noDiscount.intdiv(100), noDiscount % 100 )
                total = subTotal
       }

      printf("------------  -----%n")
      printf("T O T A L     %2d.%02d %n", total.intdiv(100), total % 100)
      printf("Thanks for Shopping!%n")
      printf("                    %n")
  
  
  
    }
  
	        def isFactor( f, n )

		// Is 'f' a factor of 'n'?

        {
 
	        return ( n % f == 0 )
        
        }





}

Java:

import java.util.ArrayList;
import java.util.HashMap;

class CheckOut

{
            private static int CUSTOMER = 0;

//Fields

			private int customer;
			private ArrayList<String> groceries = new ArrayList<String>();
			private HashMap<String, Integer> food = new HashMap<String, Integer>();

//Constructor

				public CheckOut ()
			{

					CUSTOMER ++;
				 this.customer = CUSTOMER;

				map.put( 5431, "Milk 1L" 99 );
				map.put( 2480, "Flour 1KG" 265 );
				map.put( 4017, "Eggs 6PK" 180 );

			}

//Methods
 		
			public void scan ( int barcode)
	         {
  			this.groceries.add(food [ barcode] );
                 }



    		public void printReceipt()

		{
     			  int subTotal  = 0;
     			  double total
     			  int discount = 100;
     			  String product;
     			  int price = 0;
   		          int noDiscount = 000;
	
      System.out.printf("     Welcome!%n" );
      System.out.printf("   Customer #%-4d %n", this.customer);
      System.out.printf("  Item        Price%n");
      System.out.printf("------------  -----%n");

 		      for  ( int item : groceries )

	             {

	               product = item.get(0);
	               price = item.get(1);
	               subTotal = subTotal + price;

	    System.out.printf( "%-9s     %2d.%02d %n", product, price / 100, price / 100  );

	             }
	             
	   System.out.printf("------------  -----%n");
	   System.out.printf("SUB-TOTAL     %2d.%02d %n", subTotal / 100, subTotal / 100);

	        	if ( isFactor( 7, this.customer ) )
	         {
	
	
	System.out.printf("Lucky-7      -%2d.%02d %n", discount / 100, discount / 100);
	        
			        if  ( subTotal < discount )
		                  total = 0.00;
	        else
				  total = subTotal - discount;
	         }
	         
	      else
	         
	         {
	               System.out.printf("Lucky-7      -%2d %02d %n", noDiscount / 100, noDiscount / 100 );
	         		      total = subTotal;
	         }

	 
	 System.out.printf("------------  -----%n");
	 System.out.printf("T O T A L     %2d.%02d %n", total / 100, total / 100);
	 System.out.printf("Thanks for Shopping!%n");
	 System.out.printf("                    %n");

	   }

	   
	   		private boolean isFactor( int f, int n )
	  // Is 'f' a factor of 'n'?

	          {

	          return ( n % f == 0 );

	          }





}

pH

No you're not (using the map correctly), you're attempting to store both a product description and a price directly in the map which won't work.

I'm presuming the 4 digit key is some form of barcode or product ID?

2 options :

- Use 2 hashmaps, both keyed on the barcode, the first storing product descriptions, the 2nd storing prices.

OR

- Create a simple class called Product which stores both a description and a price : the code then would look roughly like this:
[PHP]
private HashMap<String, Product> food = new HashMap<String, Product>();

...

food.put("1111",new Product("Fish", 199));
food.put("1112",new Product("Dogfood", 49));[/PHP]

sleepyescapade

pH wrote: »

No you're not (using the map correctly), you're attempt the store both a product description and a price directly in the map which won't work.

I'm presuming the 4 digit key is some form of barcode or product ID?

2 options :

- Use 2 hashmaps, both keyed on the barcode, the first storing product descriptions, the 2nd storing prices.

OR

- Create a simple class called Product which stores both a description and a price : the code then would look roughly like this:
[PHP]
private HashMap<String, Product> food = new HashMap<String, Product>();

...

food.put("1111",new Product("Fish", 199));
food.put("1112",new Product("Dogfood", 49));[/PHP]

Thanks very much i'll give it a go