Question

I have to read from a file, so made:

cod_order (int)
cod_cliente (int)
cod_pizza (int)
num_pizza (int)
cod_pizza
num_pizza
...
$FINE

here is an example:

1
1107
02
1
01
5
03
2
$FINE

I created this method to read from this text file:

private void loadOrdini(String fname){

    try{

        BufferedReader reader = new BufferedReader(new FileReader(fname));

        String cod_ordine = reader.readLine();
        while(cod_ordine!=null){

            String cod_cliente=reader.readLine();

            Cliente cl=listaclienti.get(Integer.parseInt(cod_cliente));

            String cod_pizza=reader.readLine();
            while(!cod_pizza.equals("$FINE")){

                String n_pizze=reader.readLine();

                Ordine ord = new Ordine(Integer.parseInt(cod_pizza),Integer.parseInt(n_pizze));

                cl.getListaOrdini().put(Integer.parseInt(cod_ordine), ord);

                cod_pizza=reader.readLine();

            }

            cod_ordine=reader.readLine();
        }

    }
    catch(IOException ioe){

        ioe.printStackTrace();
    }

}

the problem is the method load into the HashMap listaordini only the numbers 03 and 2 while the numbers before aren’t considerer.why?

import java.util.*;

public class Cliente{

private String name;
private String address;

private Map<Integer,Ordine> listaordini;

public Cliente(String n,String addr){

    name=n;
    address=addr;

    listaordini=new HashMap<Integer,Ordine>();
}

public String getName(){

    return name;
}

public String getAddr(){

    return address;
}

public Map<Integer,Ordine> getListaOrdini(){

    return listaordini;
}

public String toString(){

    String temp="";

    temp+="Nome Cliente: "+name;
    temp+="\nIndirizzo: "+address;

    return temp;
}

}

even after this suggets the problem remain the same

Answer 1

I think the other answers have missed the point: you want a mapping from order IDs to pizzas.

The problem is, a map (such as a HashMap) must have a unique mapping for each key. What that means is, you can only map a single Ordine to the order ID, a map doesn’t support having multiple Ordines for the same order ID.

There’s a couple of ways around this. You could make a new object that contains a list of Orders and put that into the map, or you could change your map to map an order ID to a List of orders.

For example, doing it the second way you would have:

// To create your map:
Map<Integer, List<Ordine>> listaordini = new HashMap<Integer, List<Ordine>>( );



// To add an order to it:
Ordine ord = new Ordine(Integer.parseInt(cod_pizza),Integer.parseInt(n_pizze));

List<Ordine> ordineList = cl.getListaOrdini( ).get(Integer.parseInt(cod_ordine));
if (ordineList == null)
{
    ordineList = new ArrayList<Ordine>( );
    cl.getListaOrdini( ).put(Integer.parseInt(cod_ordine), ordineList);
}

ordineList.add(ord);