ant - compare two lists

How to compare two lists in ant? Basically I am gett开发者_开发百科ing all the message_id's from the database for all my id's and want to compare them to the same id's after some messages in database are deleted.

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A very simple one assuming the lists are exactly identical in num of lines, charcters, whitespace etc., this would yield a match, else the property will not be set.

<condition property="comp" value="the files match">   
<filesmatch file1="a.txt" file2="b.txt"/> 
</condition> 

<echo> !!!! </echo>
<echo> ${comp}</echo>
<echo> !!!! </echo>