Java8: HashMap to HashMap using Stream / Map-Reduce / Collector

Question

I know how to \"transform\" a simple Java List from Y -> Z, i.e.:

List x;
List y = x.stre         


        

Answer 1

If you don't mind using 3rd party libraries, my cyclops-react lib has extensions for all JDK Collection types, including Map. We can just transform the map directly using the 'map' operator (by default map acts on the values in the map).

   MapX y = MapX.fromMap(HashMaps.of("hello","1"))
                                .map(Integer::parseInt);

bimap can be used to transform the keys and values at the same time

  MapX y = MapX.fromMap(HashMaps.of("hello","1"))
                               .bimap(this::newKey,Integer::parseInt);