MapValueSet<K, V> constructor

MapValueSet<K, V>(Map<K, V> base, K keyForValue(V value))

Creates a new MapValueSet based on base.

keyForValue returns the key in the map that should be associated with the given value. The set's notion of equality is identical to the equality of the return values of keyForValue.

Implementation 

MapValueSet(Map<K, V> base, K keyForValue(V value))
    : _baseMap = base,
      _keyForValue = keyForValue;