Tree Map Sort & foreign languages

[E Robb]

I have a tree map that I want to sort on the key. Works fine as long as you use english. When you get into other languages that have accents the sort does not work correctly. In java script there is a call you can use for a more natural search called localeCompare.

Is there a way in java to make a TreeMap have a more natural search?

Map<String, String> optList = new HashMap();
     optList.put("ztest", "06");
     optList.put("btest", "01"); 
     optList.put("ctest", "05"); 
      

Map sortedMap = new TreeMap(optList);

sortedMap returns btest, ctest, ztest in the correct order. Now if you add a character like optList.put("ét", "1") to the hashmap ét and run it through the tree map it always returns it at the end of the list instead of between ctest & ztest key.

Can a TreeMap do a natural sort that will understand that order of the keys returned should be btest, ctest, ét, ztest?

Thanks

[Paul Clapham]

Yes, because you can create a TreeMap which uses a Comparator which you define.

If you check out the API documentation for Comparator you will see that one of the standard classes which implements it is Collator. So for example if you wanted to collate strings according to the rules for French (as per your example), you could use

Collator.getInstance(Locale.FRENCH)

to make that happen. Like this:

Map<String, String> optList = new TreeMap(Collator.getInstance(Locale.FRENCH));

[E Robb]

Brilliant thank you!