Java Stream: find an element with a min/max value of an attribute

Question

I have a stream of objects and I would like to find the one with a maximal value of some attribute that\'s expensive to calculate.

As a specific simple example, say

Answer 1

Thanks everyone for suggestions. At last I found the solution I like the most at Efficiency of the way comparator works -- the answer from bayou.io:

Have a general purpose cache method:

public static  Function cache(Function f, Map cache)
{
    return k -> cache.computeIfAbsent(k, f);
}

public static  Function cache(Function f)
{
    return cache(f, new IdentityHashMap<>());
}

This could then be used as follows:

String coolestString = stringList
        .stream()
        .max(Comparator.comparing(cache(CoolUtil::coolnessIndex)))
        .orElse(null);