Sorting a Vector by multiple criteria

Question

Hi,
I am trying to sort a Vector by multiple criteria. For example, the Vector must first be sorted by category 1, then category 2, etc.
This is my code so far:
Vector<Item> temp = new Vector<Item>(items.size());
Collections.sort(temp, new ByFilename());
Collections.sort(temp, new BySong());
Collections.sort(temp, new ByArtist());
     private static class Item
          String CD, track, song, artist, details, filename;
          int row;
          Item(String c, String t, String s, String a, String d, String f, int r)
               CD = c;
               track = t;
               song = s;
               artist = a;
               details = d;
               filename = f;
               row = r;
     private static class ByFilename implements Comparator<Item>
          public int compare (Item one, Item two)
               return  one.filename.compareTo(two.filename);
     private static class BySong implements Comparator<Item>
          public int compare (Item one, Item two)
               return  one.song.compareTo(two.song);
     private static class ByArtist implements Comparator<Item>
          public int compare (Item one, Item two)
               return  one.artist.compareTo(two.artist);
     }Except this sorts the Vector by Filename, then sorts again from scratch by song, then again from scratch by artist. However, I want it sorted by Filename, with the duplicate Filenames sorted by song, and entries with the same Filename and songs, sorted by artist. I hope this makes sense!!
Does anyone have any ideas? I tried sorting by filename, finding the duplicates, sorting these in a separate vector and then adding back in, but it didn't work and was too messy. There has to be an easier way... that is much less fiddly.
Thanks in advance for any help :)

Answer 1

Here's a demo of using chained comparators.
import java.util.*;
public class Item {
    String a, b, c;
    public Item(String a, String b, String c) {
        this.a = a;
        this.b = b;
        this.c = c;
    public String toString() {
        return  a +  b + c;
    public static void main(String[] args) {
        Item[] items = {
            new Item("0","1","1"),
            new Item("1","1","1"),
            new Item("0","1","0"),
            new Item("1","1","0"),
            new Item("0","0","1"),
            new Item("1","0","1"),
            new Item("0","0","0"),
            new Item("1","0","0"),
        Arrays.sort(items, new ByA(new ByB(new ByC(null))));
        System.out.println(Arrays.toString(items));
class ByA implements Comparator<Item> {
    Comparator<Item> tieBreaker;
    ByA(Comparator<Item> tieBreaker) {
        this.tieBreaker = tieBreaker;
    public int compare (Item one, Item two){
        int result = one.a.compareTo(two.a);
        if (result == 0 && tieBreaker != null) {
            result = tieBreaker.compare(one, two);
        return result;
class ByB implements Comparator<Item> {
    Comparator<Item> tieBreaker;
    ByB(Comparator<Item> tieBreaker) {
        this.tieBreaker = tieBreaker;
    public int compare (Item one, Item two){
        int result = one.b.compareTo(two.b);
        if (result == 0 && tieBreaker != null) {
            result = tieBreaker.compare(one, two);
        return result;
class ByC implements Comparator<Item> {
    Comparator<Item> tieBreaker;
    ByC(Comparator<Item> tieBreaker) {
        this.tieBreaker = tieBreaker;
    public int compare (Item one, Item two){
        int result = one.c.compareTo(two.c);
        if (result == 0 && tieBreaker != null) {
            result = tieBreaker.compare(one, two);
        return result;
}