collections - Why java.util.Set does not contain value getter? Are there alternatives to it? -

as set entries distinguished subset of properties (hashcode() + equals()), there need operate on original object contained in set, not possible java.util.set. alternative came is: map<t, t> - not concise solution.

are there other alternatives in collections framework? requirements are: o(1) fetch time , no duplicates based on hashcode() + equals() result.

if 1 more o(1) operation not problem, can simulate absenting method get(object) pair of methods set.remove(object) , set.add(object). otherwise, use map<t,t> mentioned or simple wrapper class underlying map.

edit: reason why set doesn't contain get(object) don't need return object know. need check, if object contained in set or not.