public boolean retainAll(ShortIterable source)
{
int oldSize = this.size();
final ShortSet sourceSet = source instanceof ShortSet ? (ShortSet) source : source.toSet();
CharShortHashMap retained = CharShortHashMap.this.select(new CharShortPredicate()
{
public boolean accept(char key, short value)
{
return sourceSet.contains(value);
}