/**
* Returns an unmodifiable set of all the attribute names.
*
* @return A set of all the attribute names
*/
public Set<String> getAttributeNames() {
return Collections.unmodifiableSet(nameToIndex.keySet());
}
/**
* Returns a view of the items currently being counted. The returned view is read-only; any
* attempts to modify this view will throw an {@link UnsupportedOperationException}.
*/
public Set<T> items() {
return Collections.unmodifiableSet(counts.keySet());
}