Question

I’d like some kind of string comparison function that preserves natural sort order¹. Is there anything like this built into Java? I can’t find anything in the String class, and the Comparator class only knows of two implementations.

I can roll my own (it’s not a very hard problem), but I’d rather not re-invent the wheel if I don’t have to.

In my specific case, I have software version strings that I want to sort. So I want “1.2.10.5” to be considered greater than “1.2.9.1”.

---

¹ By “natural” sort order, I mean it compares strings the way a human would compare them, as opposed to “ascii-betical” sort ordering that only makes sense to programmers. In other words, “image9.jpg” is less than “image10.jpg”, and “album1set2page9photo1.jpg” is less than “album1set2page10photo5.jpg”, and “1.2.9.1” is less than “1.2.10.5”

Answer 1

In java the “natural” order meaning is “lexicographical” order, so there is no implementation in the core like the one you’re looking for.

There are open source implementations.

Here’s one:

NaturalOrderComparator.java

Make sure you read the:

Cougaar Open Source License

I hope this helps!