• From: Philippe Poulard <Philippe.Poulard@s...>
• To: Fraser Goffin <goffinf@g...>
• Date: Thu, 02 Aug 2007 20:28:10 +0200

Fraser Goffin a écrit :
> Has anyone come across a good Java library for comparing XML instances ?
>  

hi,

you should consider XUnit :
http://reflex.gforge.inria.fr/xunit.html

XUnit does the same than JUnit, but if you have to compare 2 XML 
documents, it might help ; usually you do you own stuff that produce 
some datas, and as you have prepared the expected datas, you just have 
to assert that the 2 datas are equals ; this is the same in XUnit, and 
the 2 datas can be 2 nodes

for example :
<xunit:test-case name="myTest" label="Testing purchase order">
     <!--run your own stuff-->
     <acme:transform-purchase-order output="result.xml" id="1234"/>

     <!--retrieve the result and the output expected-->
     <xcl:parse name="po" source="result.xml"/>
     <xcl:parse name="oe" source="output-expected.xml"/>

     <!--check if they are equals-->
     <xunit:assert-node-equals result="{ $po }" expected="{ $oe }" 
recurse="true"/>
</xunit:test-case>

the tool works on the DOM, and it will report each difference found (for 
example when an attribute is missing, or when an attribute is not 
expected, or when the attribute values don't match) ; at a given level, 
if 2 elements don't match, the tool won't look inside their content

exemple of report :
http://reflex.gforge.inria.fr/xunit.html#checkingTheErrorReport
(if you scroll down a little, you'll find an HTML-formatted output)

it is simple, but efficient ; the output report contains the canonical 
path of each node in fault (the canonical path is the XPath expression 
that starts from the root and descend child from child by naming it and 
setting its position regarding its parent : e.g. /root[1]/elem[5]/@attr)
namespace URIs are supplied if you have any, and they don't clash even 
if some have been remapped in the documents

enjoy !

-- 
Cordialement,

               ///
              (. .)
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|      Philippe Poulard       |
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  http://reflex.gforge.inria.fr/
        Have the RefleX !