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javaooparraylistmethods
KicksheepSon
KicksheepSon

Reputation: 67

Java How to handle multiple return Values?

Let's assume I have got a List of Flight Objects

public class Flight {
    private int passengers;
    private int price
    ...

    //getters and Setters
}

List<Flight> flightList = new ArrayList<Flight>();

Now i need to accumulate price per passenger and the Price, because I have to be able to proceed both informations later on. so I would create two methods:

public int calculatePrice(List<Flight> flightList) {
    int price = 0;
    for (Flight flight : flightList) {
        price = price + flight.getPrice();
    }
    return price;
}

public int calculatePricePerPassengers(List<Flight> flightList) {
    int pricePerPassenger = 0;
    for (Flight flight : flightList) {
        pricePerPassenger = (pricePerPassenger) + (flight.getPrice() / flight.getPassgers());
    }
    return pricePerPassenger;
}

I have got like 4-5 methods of the same type. I am not sure whether there is too much redundancy, because I call the for loop 4-5 Times and I could easily do all the operations in one for loop, but that would have the effect of multiple return values. So is this the appropriate way ? (just a dummy example)

Upvotes: 2

Views: 287

Answers (3)

MAV
MAV

Reputation: 26

It all comes down to what are the functionalities that you want to provide to the user. So if the user expects to be able to calculate both prices individually then I do not see any other way around what you have. But if you can present both prices at once, then you can eliminate one of the methods and loop only once trough your Flight list and return a composition of both prices. ex:

public static Pair[] calculatePrices(List<Flight> flightList)
{
     int pricePerFlight= 0;
     int pricePerPassenger = 0;
     for(Flight flight : flightList)
    {
       pricePerFlight = pricePerFlight + flight.getPrice();
       pricePerPassenger =   pricePerPassenger  +(flight.getPrice()/flight.getPassgers());

     }
    return new Pair[] {new Pair<>("pricePerFlight", pricePerFlight), new Pair<>("pricePerPassenger", pricePerPassenger )};
}

Upvotes: 0

Antony H
Antony H

Reputation: 40

You could wrap those two values into a new array:

public int[] calculatePrices(List<Flight> flightList) {

    int totalPrice = 0;
    int pricePerCustomer = 0;

    for (Flight flight : flightList) {
        totalPrice += flight.getPrice();
        pricePerCustomer += (flight.getPrice() / flight.getPassgers());
    }

    return new int[] { totalPrice, pricePerCustomer };
}

Upvotes: 1

Amit Bera
Amit Bera

Reputation: 7325

You can use map for that or also you can warp all the fields you want to return in a class. Here I am giving the example using Map.

public static Map<String, Integer> calculatePrice(List<Flight> flightList) {
    Map<String, Integer> priceMap = new HashMap<>();
    int price = 0;
    int pricePerPassenger = 0;
    for (Flight flight : flightList) {
        price = price + flight.getPrice();
        pricePerPassenger = (pricePerPassenger) + (flight.getPrice() / flight.getPassgers());
    }
    priceMap.put("price", price);
    priceMap.put("pricePerPassenger", pricePerPassenger);
    return priceMap;
}

EDIT: Example using a wrapper class (DTO).

    public static FligtPriceDTO calculatePrice(List<Flight> flightList) {
        FligtPriceDTO dto = new FligtPriceDTO();
        int price = 0;
        int pricePerPassenger = 0;
        for (Flight flight : flightList) {
            price = price + flight.getPrice();
            pricePerPassenger = (pricePerPassenger) + (flight.getPrice() / flight.getPassgers());
        }
        dto.setPrice(price);
        dto.setPricePerPassenger(pricePerPassenger);
        return dto;
    }
}

class FligtPriceDTO {
    private int price;
    private int pricePerPassenger;

    public int getPrice() {
        return price;
    }

    public void setPrice(int price) {
        this.price = price;
    }

    public int getPricePerPassenger() {
        return pricePerPassenger;
    }

    public void setPricePerPassenger(int pricePerPassenger) {
        this.pricePerPassenger = pricePerPassenger;
    }

}

Upvotes: 5

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