How to compute the hash code for a stream in the same way as List.hashCode()

Question

I just realized that implementing the following algorithm to compute the hash code for a stream is not possible using Stream.reduce(...). The problem is that the initial see

Answer 1

Holger wrote the right solution, if you want a simple way of doing it there are two additional possibilities:

1. collect to List and call hashCode()

Stream stream;
int hashCode = stream.collect(toList()).hashCode();

2. use Stream.iterator()

Stream stream;
Iterator iter = stream.iterator();
int hashCode = 1;
while(iter.hasNext()) {
  hashCode = 31 *hashCode + Objects.hashCode(iter.next());
}

Just as a reminder the algorithm that List.hashCode() uses:

int hashCode = 1;
for (E e : list)
  hashCode = 31*hashCode + (e==null ? 0 : e.hashCode());