I want to translate a List of objects into a Map using Java 8's streams and lambdas.
This is how I would write it in Java 7 and below.
private Map<String, Choice> nameMap(List<Choice> choices)
{ final Map<String, Choice> hashMap = new HashMap<>();
for (final Choice choice : choices)
{ hashMap.put(choice.getName(), choice); }
return hashMap; }
I can accomplish this easily using Java 8 and Guava but I would like to know how to do this without Guava.
In Guava:
private Map<String, Choice> nameMap(List<Choice> choices)
{ return Maps.uniqueIndex(choices, new Function<Choice, String>()
{ @Override public String apply(final Choice input)
{ return input.getName(); } });
}
And Guava with Java 8 lambdas.
private Map<String, Choice> nameMap(List<Choice> choices) { return Maps.uniqueIndex(choices, Choice::getName);
}