I have two sets:
val Set<Integer> setA = #{1, 2, 3}
val Set<Integer> setB = #{3, 4, 5} + setA
I would expect setB to contain 1, 2, 3, 4, 5.
However, the + operator returns an instance of Iterable, instead of a Set.
Are there any xtend shortcuts that would allow me to do what I want?
I'm afraid there is no backed in support for a union. You may want to add an operator_plus for two sets and delegate to Guavas Sets.union.
def <T> Set<? extends T> operator_plus(Set<? extends T> left, Set<? extends T> right) {
return Sets.union(left, right)
}
Without redefining operators, you have to convert the Iterable to a Set manually.
val Set<Integer> setA = #{1, 2, 3}
val Set<Integer> setB = (#{3, 4, 5} + setA).toSet
If you have a mutable set, there is one other way: The += operator, which is a shortcut for addAll on any collection.
val Set<Integer> setA = #{1, 2, 3}
val Set<Integer> setB = newHashSet(3, 4, 5)
setB += setA
Neither solution look particularly nice and you probably want to avoid mutability.
As suggested in the other answer, Guava's Sets.union method might come in handy, though I would rather import it as static extension than redefining operators. Then you can use:
val Set<Integer> setA = #{1, 2, 3}
val Set<Integer> setB = #{3, 4, 5}.union(setA)
Be careful though, union returns a view of both sets, which can change if the underlying sets are mutable.
