Task01Main.java

package com.example.task01;

import java.io.IOException;
import java.util.Objects;
import java.util.function.Function;
import java.util.function.Predicate;

public class Task01Main
{
    public static void main(String[] args) throws IOException
    {
        Predicate<Object> condition = Objects::isNull;
        Function<Object, Integer> ifTrue = obj -> 0;
        Function<CharSequence, Integer> ifFalse = CharSequence::length;
        Function<String, Integer> safeStringLength = ternaryOperator(condition, ifTrue, ifFalse);
    }

    public static <T, U> Function<T, U> ternaryOperator(
            Predicate<? super T> condition,
            Function<? super T, ? extends U> ifTrue,
            Function<? super T, ? extends U> ifFalse)
    {
        if(condition == null || ifTrue == null || ifFalse == null)
        {
            throw new NullPointerException();
        }

        return obj ->
        {
            if(condition.test(obj))
            {
                return ifTrue.apply(obj);
            }

            return ifFalse.apply(obj);
        };
    }
}