package Item37;

import Item37.java.Planet;

import java.util.*;

import static java.util.stream.Collectors.groupingBy;

import static java.util.stream.Collectors.toSet;

public class Usage {

static Planet[] garden = new Planet[0]; // fake

public static void main(String[] args){

// Using ordinal() to index into an array - DON"T DO THIS !!!

Set<Planet>[] planetsByLifeCycle = (Set<Planet>[]) new Set[Planet.LifeCycle.values().length];

for (int i = 0; i < planetsByLifeCycle.length; i++)

planetsByLifeCycle[i] = new HashSet<>();

for (Planet p : garden)

planetsByLifeCycle[p.lifeCycle.ordinal()].add(p);

for (int i = 0; i < planetsByLifeCycle.length; i++)

System.out.printf("%s: %s%n", Planet.LifeCycle.values()[i], planetsByLifeCycle[i]);

//-----------------------------------------

//Using EnumMap to associate data with an enum --1st version--

Map<Planet.LifeCycle, Set<Planet>> plantsByLifeCycle = new EnumMap<Planet.LifeCycle, Set<Planet>>(Planet.LifeCycle.class);

for (Planet.LifeCycle pl: Planet.LifeCycle.values())

plantsByLifeCycle.put(pl, new HashSet<>());

for (Planet p : garden)

plantsByLifeCycle.get(p.lifeCycle).add(p);

System.out.println(plantsByLifeCycle);

//------------------------------------------

// Using Stream with EnumMap --2nd version--

System.out.println(Arrays.stream(garden).collect(groupingBy(p -> p.lifeCycle, () -> new EnumMap<>(Planet.LifeCycle.class), toSet())));

}

}