Convert stream into a for loop java

Question

I kind of need this stream reverse engineered into a for loop. How would it look?

public Optional<Flight> getFlightByFlightNumber(String flightNumber) {
    return flights.stream()
            .filter(flt -> flt.getFlightNumber().equals(flightNumber))
            .findFirst();
}

just check what it does. That should already show you how to convert it. — Stultuske
– Stultuske, Commented Apr 25, 2022 at 5:55

Shridutt Kothari · Accepted Answer · 2022-04-25 06:04:13Z

2

It will something like this:

public Optional<Flight> getFlightByFlightNumber(String flightNumber) {
    Flight flightByFlightNumber = null;
    for (Flight flight : flights) {
        //You might want to add a null check here before calling equals method, to avoid NullPointerException
        if (flight.getFlightNumber().equals(flightNumber)) {
            flightByFlightNumber = flight;
            // breaking the loop as we found first match
            break;
        }
    }
    return Optional.ofNullable(flightByFlightNumber);
}

edited Apr 25, 2022 at 6:04

answered Apr 25, 2022 at 6:00

Shridutt Kothari

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2 Comments

Stultuske Over a year ago

yet there is one big difference between the original code and this

Shridutt Kothari Over a year ago

@Stultuske Thanks for the hint, added the break statement

WJS · Accepted Answer · 2022-04-25 13:16:04Z

0

Here is one way.

just iterate over the list until the flight is found and return directly in an Optional.
otherwise, return an empty optional when the loop finishes.

public Optional<Flight> getFlightByFlightNumber(String flightNumber) {
    for (Flight flight : flights) {
        if (flight.getFlightNumber.equals(flightNumber)) {
            return Optional.of(flight);
        }
    }
    return Optional.empty();
}

answered Apr 25, 2022 at 13:16

WJS

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