/**
* @param a
* @param b
* @return
*/
public static <T1, T2, L extends List<? super T1>, R extends List<? super T2>>
Difference<L, R> of(Collection<T1> a, Collection<T2> b) {
List<T1> common = new ArrayList<>();
List<T1> leftOnly = new ArrayList<>();
List<T2> rightOnly = new ArrayList<>();
if (N.isNullOrEmpty(a)) {
if (N.isNullOrEmpty(b)) {
// Do nothing. All empty.
} else {
rightOnly.addAll(b);
}
} else if (N.isNullOrEmpty(b)) {
leftOnly.addAll(a);
} else {
common = N.intersect(a, b);
leftOnly = N.except(a, b);
rightOnly = N.except(b, a);
}
return new Difference<>((L) common, (L) leftOnly, (R) rightOnly);
}
