Sort List of Strings with Localization

Question

I want to sort below List of strings as per user locale

List<String> words = Arrays.asList(
      "Äbc", "äbc", "Àbc", "àbc", "Abc", "abc", "ABC"
    );

For different user locale sort output should be different as per there locale.

How to sort above list as per user locale ?

I tried

Collections.sort(words , String.CASE_INSENSITIVE_ORDER);

But this is not working for localization, so how to pass locale parameter to Collections.sort() or is there any other efficient way ?

your output is [Abc, abc, ABC, Àbc, àbc, Äbc, äbc] after sorting. isn't this correct? i think sorting is already based on 1-alphabetical order 2-locale order. — Juvanis, Oct 15 '12 at 05:39
Sorting should consider base char , accent , case , bits. So output should be [abc, Abc, ABC, àbc, Àbc, äbc, Äbc] for FRANCE locale — Rahul Agrawal, Oct 15 '12 at 05:43

score 63 · Accepted Answer · edited Feb 18 '16 at 09:20

63

You can use a sort with a custom Comparator. See the Collator interface

Collator coll = Collator.getInstance(locale);
coll.setStrength(Collator.PRIMARY);
Collections.sort(words, coll);

The collator is a comparator and can be passed directly to the Collections.sort(...) method.

edited Feb 18 '16 at 09:20

Kerem Baydoğan

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answered Oct 15 '12 at 05:40

John Dvorak

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@kerem why did you remove the attribution? – John Dvorak Feb 18 '16 at 09:46
Jan sorry if i did something wrong. Collator.PRIMARY is discussed in the next answer with details, and it is obvious that you get the idea from @Bhesh. – Kerem Baydoğan Feb 18 '16 at 11:54

Bhesh Gurung · Answer 2 · 2012-10-15T05:58:17.687

29

I think this what you should be using - Collator

The Collator class performs locale-sensitive String comparison. You use this class to build searching and sorting routines for natural language text.

Do something as follows in your comparator -

public int compare(String arg1, Sting arg2) {
    Collator usCollator = Collator.getInstance(Locale.US); //Your locale here
    usCollator.setStrength(Collator.PRIMARY);
    return usCollator.compare(arg1, arg2);
}

And pass an instance of the comparator the Collections.sort method.

Update

Like @Jan Dvorak said, it actually is a comparator, so you can just create it's intance with the desired locale, set the strength and pass it the sort method:

Collactor usCollator = Collator.getInstance(Locale.US); //Your locale here
usCollator.setStrength(Collator.PRIMARY); //desired strength
Collections.sort(yourList, usCollator);

edited Oct 15 '12 at 05:58

answered Oct 15 '12 at 05:41

Bhesh Gurung

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What does Collator.PRIMARY will do ? – Rahul Agrawal Oct 15 '12 at 05:46
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@RahulAgrawal: It's the strength of comparision. Please read the documentation, you will find a detailed explanation there. That's where I borrowed the example from. – Bhesh Gurung Oct 15 '12 at 05:50
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The collator IS a comparator. I just found out. – John Dvorak Oct 15 '12 at 05:53
@JanDvorak Ohh Collator is a Comparator, which does support I18N .. :) – Rahul Agrawal Oct 15 '12 at 06:02
@RahulAgrawal I admit I shouldn't be surprised that a Collator is a Comparator :-) – John Dvorak Oct 15 '12 at 06:05
The Comparator with Locale.GERMAN doesn't sort correctly. Our rules are somewhat complicated, but nonetheless. – Holger Jakobs Dec 25 '16 at 19:48

Mehmet Onar · Answer 3 · 2019-04-02T05:32:27.883

9

List<MODEL> ulke = new ArrayList<MODEL>();

    Collections.sort(ulke, new Comparator<MODEL>() {
        Collator collator = Collator.getInstance(new Locale("tr-TR"));
        @Override
        public int compare(MODEL o1, MODEL o2) {
            return collator.compare(o1.getULKEAD(), o2.getULKEAD());
        }
    });

edited Apr 02 '19 at 05:32

answered Apr 01 '19 at 14:11

Mehmet Onar

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While this code may solve the question, [including an explanation](//meta.stackexchange.com/q/114762) of how and why this solves the problem would really help to improve the quality of your post, and probably result in more up-votes. Remember that you are answering the question for readers in the future, not just the person asking now. Please [edit] your answer to add explanations and give an indication of what limitations and assumptions apply. – Suraj Rao Apr 01 '19 at 14:49

Sort List of Strings with Localization

3 Answers3

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