CODEWITHSUNDEEP
javaconditional-operator
TheLovelySausage
TheLovelySausage

Reputation: 4094

Ternary If that includes a functions result

I was just wondering if there's a more efficient way to do something along the lines of this in Java.

Just going to use this dummy function as an example

static int getDivision(int number, int divider) {
    if(divider == 0) { return -1; }
    return (number / divider);
}

If I have a ternary operator that is checking the result of that function like the below

public static void main(String[] args) {

    int result;

    result = getDivision(2, 0);
    System.out.println (
        result == -1 ? "No" : result
    );

}

I have to create a variable to store the result, otherwise I can do it like this

    System.out.println (
        getDivision(2, 0) == -1 ? "No" : getDivision(2, 0)
    );

But I have to call the function twice which is even worse. Is it possible to use the ternary operator but include the result of a function in the conditions?

    System.out.println (
        getDivision(2, 0) == -1 ? "No" : /*returned result*/
    );

Upvotes: 1

Views: 60

Answers (1)

Peter Walser
Peter Walser

Reputation: 15706

Using Optional, you can represent a real result as well as indicate that no result is present:

static Optional<Integer> getDivision(int number, int divider) {
    return divider == 0 ? Optional.empty() : Optional.of(number / divider);
}

Usage:

Optional<Integer> result = getDivision(2, 0);
System.out.println(result.map(String::valueOf).orElse("No"));

Or if you only want to further process the result when it is present:

result.ifPresent( value -> ...);

EDIT: the value -1 is also a valid outcome of some divisions, which works fine with the Optional as well, compared to the original approach:

Optional<Integer> result = getDivision(-5, 5);

Upvotes: 4

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