Thread: Regular Expression To Catch Duplicates

I want to know how to use "matches()" to catch when a duplicate appears in my String "xmlString" (which contains an xml file).

So for example the following fragment should return "false":

<Countries>
<Country>BE</Country>
<Country>DE</Country>
<Country>GB</Country>
</Countries>

Whereas the following fragment should return "true":

<Countries>
<Country>BE</Country>
<Country>DE</Country>
<Country>GB</Country>
<Country>DE</Country>
</Countries>

So far my comparison looks like this:

boolean containsDuplicateCountry = xmlString.matches(".*<Country>[A-Z]{2}</Country>.*");

which just returns "true" for any upper case 2 digit territory code. I have no idea how to amend this to check for a duplicate. Any ideas would be really appreciated. Thanks,

Daniel