package betsy.common.util;
import java.util.LinkedList;
import java.util.List;
public class CollectionsUtil {
public static <T> List<T> union(List<List<T>> collections) {
if (collections.size() <= 0) {
return new LinkedList<>();
} else if (collections.size() == 1) {
return collections.get(0);
} else {
List<T> result = new LinkedList<>();
for (List<T> list : collections) {
result.addAll(list);
}
return result;
}
}
}