alphanumeric-comparator

An alphanumeric comparator in Java, for comparing and sorting strings in a more human readable format. It uses a combination of numeric and alphabetic comparisons to compare two strings. This class uses standard Java classes and is independent of any 3rd party libraries.

Additionally this comparator uses java.text.Collator class to correctly sort strings containing special characters like Umlauts or similar alphabet letters in different languages, such as: å, è, ü, ö, ø, or ý.

Example #1

For given list of strings:

file-01.doc, file-2.doc, file-03.doc

A regular lexicographical sort, e.g. java.util.Collections.sort(), sorts the above list in the following order:

file-01.doc, file-03.doc, file-2.doc

However using AlphaNumericComparator, the list will be sorted in a more meaningful and readable way:

file-01.doc, file-2.doc, file-03.doc

Example #2

For the following list of unsorted characters/strings:

b, e, k, ě, f, è, g

A regular lexicographical sort, e.g. java.util.Collections.sort(), sorts the above list in the following order:

b, e, f, g, k, è, ě

Using AlphaNumericComparator, the list is correctly sorted as below:

b, e, è, ě, f, g, k

Example #3

Consider the following unsorted list of words:

sèle, solo, solè, sola, soli, sole, sold, sila, silè, sölo, sulo, sylo, soly

Using Java Collections.sort() we will have:

sila, silè, sola, sold, sole, soli, solo, soly, solè, sulo, sylo, sèle, sölo

However with AlphaNumericComparator sort we will have a more accurate sorted list:

sèle, sila, silè, sola, sold, sole, solè, soli, solo, soly, sölo, sulo, sylo

How To

Simply pass the comparator as a parameter when sorting a list of strings:

List<String> list = new ArrayList<String>();
list.add("some string");
list.add("some other string");
...
list.sort(new AlphaNumericComparator());

or just simply use the compare() method in AlphaNumericComparator if needed to compare two strings.