XPath Problem

Dear All,
  Does any doby tell me how to use xpath. My Domain.xml contains following:-
  <extractors>
  <extractor classname="org.apache.slide.extractor.SimpleXmlExtractor" uri="/files">
  <configuration>
  <instruction property="title" xpath="/article/title/text()" />
  <instruction property="summary" xpath="/article/summary/text()" />
  </configuration>
  </extractor>
  </extractors>
   
  Problem:- I could not understand what is xpath here and where these title, and summary exist.
   
  Actually i have contains many XML files in my slide store. I want to use a extractor that index xml value content as well as the Nodes name also, so that i can search by the Node's Name. Example
   
  sample.xml file
  <Root>
  <Circle extents"90">
          Register,  City, 89, 77
   
  </Circle>
  </Root>
   
  Now I want to search by Circle, extents and root also. Currently it can search only contents like Register, City.
   
  Anydoby help me?
  Thanks...

 				
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