XPathGen

Simple Java utility class for generating a unique XPath for a given DOM node.

E.g.

        Document testDoc = createDocument(
                "<a>aa<b attr='test'>b<!-- comment -->c<c/></b>d</a>");
                
        //Grab text node "aa"
        Node aa = testDoc.getDocumentElement().getFirstChild(); 
        
        System.out.println(XPathGen.getXPath(aa));
        
        //Should print "/node()[1]/node()[1]"

This code has been taken from diffxml (http://diffxml.sourceforge.net), slightly simplified and relicensed under the Apache licence V2. (Note that diffxml was released under a GPL license which I've relicensed here to allow for commercial use.)

There are also a few extra methods you might find useful:

- copyNodeToDoc   which copies an element with any attributes but no children
                  from one document to another
- getLocalName    which just returns the local name of the node, falling back
                  to the node name if this is null
- isNamespaceAttr which returns true if the node is a namespace declaration
- isText          which returns true if the node is a CDATA or text node

The code has been simplified slightly by removing support for ignoring nodes and calculating text offsets (in DOM it is possible to have two adjacent text nodes but these are seen as a single node in XPath, which requires the use of offsets and length attributes to work around). The ChildNumber class is still more complicated than it needs to be however.

For more usage details see "Example.java" and the JUnit tests.

XPathGen has been tested with Java SE 6. If you want to run the tests you will need JUnit 4.

Possible improvements:

• Using node names rather than numbers
• Simplify ChildNumber class (subsume into XPathGen?)
• Add an interface class to hide details

Adrian Mouat