组合谓词练习 JAVA hyperskill

Question

I am practicing my java skills on Hyperskill and I cant figure out this excercise about composing predicates.

Write the disjunctAll method that accepts a list of IntPredicate's and returns a single IntPredicate. The result predicate is a disjunction of all input predicates.

If the input list is empty then the result predicate should return false for any integer value (always false).

Important. Pay attention to the provided method template. Do not change it.

public static IntPredicate disjunctAll(List<IntPredicate> predicates) {

}

Answer 1

A simple iteration of the list would do it:

    public static IntPredicate disjunctAll(List<IntPredicate> predicates)
    {
        IntPredicate result = i -> false;
        for (IntPredicate p: predicates) {
            result = p.or(result);
        }
        return result;
    }

or simply with a stream reducer:

    public static IntPredicate disjunctAll(List<IntPredicate> predicates)
    {
        return predicates.stream()
            .reduce(i -> false, IntPredicate::or);
    }