Java Stream - 如何过滤，然后排序，然后映射和转换为列表

import java.util.*;
import java.util.stream.Collectors;

class DataSet {
        public final String name;
        public final Set<Integer> data;
        public DataSet(final String name, final Integer ... seasons) {
            this.name = name;
            this.data = Collections.unmodifiableSet(new TreeSet<>(Arrays.asList(seasons)));
        }
}
public class Main {
    private static final List<DataSet> CHARACTERS = Collections.unmodifiableList(Arrays.asList(
            new DataSet("A", 1, 2, 3, 4, 5),
            new DataSet("B", 2, 3, 4, 5),
            new DataSet("C", 1, 2, 3),
            new DataSet("D", 3, 4),
            new DataSet("E", 3, 4, 5),
            new DataSet("F", 5),
            new DataSet("G", 2),
            new DataSet("H", 1, 2),
            new DataSet("I", 1, 2, 3)
    ));

    public static void main(final String ... args) {
        final List<String> docks = CHARACTERS.stream()
                        .filter(c -> c.data.contains(2))
                        .sorted((a, b) -> a.data.size() - b.data.size())
                        .map(c -> c.name)
                        .collect(Collectors.toList());

        System.out.println(docks);
    }

}