Find duplicated XML Element Names (xPath with variable)

Question

I\'m using XPATH 1.0 parsers alongside CLiXML in my JAVA project, I\'m trying to setup a CLiXML constraint rules file.

I would like to show an error if there are duplica

Answer 1

Just try to get list of subnodes with appropriate path expression and check for duplicates in that list:

   XPathExpression xPathExpression = xPath.compile("//parentNode/*");
   NodeList children = (NodeList) xPathExpression.evaluate(config, XPathConstants.NODESET);

   for (int i = 0; i < children.getLength(); i++) {
   // maintain hashset of clients here and check if element is already there
   }

Answer 2

This cannot be done with a single XPath 1.0 expression (see this similar question I answered today).

Here is a single XPath 2.0 expression (in case you can use XPath 2.0):

/*/*[(for $n in name() 
      return count(/*/*[name()=$n]) 
      )
     >1
     ]

This selects all elements that are children of the top element of the XML document and that occur more than once.