Java 8 filter based on a boolean

Question

I want to be able to apply a filter based on the boolean passed in.

public static List<Integer> multiplyNumbers(List<Integer> input, boolean ignoreEven){

    return input.stream()
    .filter(number -> !(number%2==0))
    .map(number -> number*2)
    .collect(Collectors.toList());
}

I want to make the filter step based on the ignoreEven flag. If its true, ignore even numbers. How do I go about doing it? I am doing this to avoid code duplication

Answer 1

Sounds like a straightforward or condition to me.

.filter(number -> !ignoreEven || (number % 2 != 0))