Removing the “first” object from a Set

Question

Under certain situations, I need to evict the oldest element in a Java Set. The set is implemented using a LinkedHashSet, which makes this simple: just get rid of t

Answer 1

I think the way you're doing it is fine. Is this something you do often enough to be worth finding a shorter way? You could do basically the same thing with Guava like this:

Iterables.removeIf(Iterables.limit(mySet, 1), Predicates.alwaysTrue());

That adds the small overhead of wrapping the set and its iterator for limiting and then calling the alwaysTrue() predicate once... doesn't seem especially worth it to me though.

Edit: To put what I said in a comment in an answer, you could create a SetMultimap that automatically restricts the number of values it can have per key like this:

SetMultimap multimap = Multimaps.newSetMultimap(map,
    new Supplier>() {
      public Set get() {
        return Sets.newSetFromMap(new LinkedHashMap() {
          @Override protected boolean removeEldestEntry(Entry eldestEntry) {
            return size() > MAX_SIZE;
          }
        });
      }
    });