JDK1.5 Xpath problem

[abcd_68]

Hi there,

I'm using, for the first time, the JDK1.5 Xpath API. I need to find
elements in a Hibernate-generated .hbm.xml file. These files come with
a <!DOCTYPE header mentioning a remote URL. The Xpath parser fetches
the URL from the hibernate.sourceforge site. So far so good.

However, if I unplug the network, I get (after a *long* timeout) a
java.net.SocketException. I looked around and I found out that I have
to define a class implementing EntityResolver to change the default
behaviour (i.e., fetch the DTD over the net) and obtain an InputSource
from it. Something along the lines of:

public class UriTransform implements EntityResolver {
public InputSource resolveEntity(String publicId, String systemId) {
return new InputSource(new StringReader(""));
}
}

Now my problem is: How do I do it? Neither in javax.xml.xpath.XPath nor
in javax.xml.xpath.XPathFactory did I find an appropriate place nor did
I find a method to gain access to the underlying SAX parser. Here's my
code:

XPath xpath = XPathFactory.newInstance().newXPath();
final String expression = "//property";
final String completePath = ... //file path
InputSource inputSource = new InputSource(completePath);
DTMNodeList nodes = (DTMNodeList) xpath.evaluate(expression,
inputSource, XPathConstants.NODESET);

Any ideas?
TIA
andy

[Martin Honnen]

ab*****@yahoo.co.uk wrote:

However, if I unplug the network, I get (after a *long* timeout) a
java.net.SocketException. I looked around and I found out that I have
to define a class implementing EntityResolver to change the default
behaviour (i.e., fetch the DTD over the net) and obtain an InputSource
from it.

Now my problem is: How do I do it? Neither in javax.xml.xpath.XPath nor
in javax.xml.xpath.XPathFactory did I find an appropriate place nor did
I find a method to gain access to the underlying SAX parser.

I don't know how to do it if you pass an InputSource to the evaluate
method. You can however also pass in an object where the object is a W3C
DOM Node. And if you look at DocumentBuilder it has a method
setEntityResolver. That should allow you to create a DOM Document
without fetching the DTD from the remote host, and you can then pass in
the Document to the evaluate method. I am not sure a DOM Node/Document
is the most efficient data structure to do XPath on but at least that
approach might work for your problem.

--

Martin Honnen
http://JavaScript.FAQTs.com/

[Joseph Kesselman]

One way around this is to instantiate the parser yourself, configure it
appropriately, then pass it to the transformer wrapped in a SAXSource.

(There ought to be a way to pass an entity resolver/URI resolver through
the XPath APIs, but I'm having trouble finding it.)

[abcd_68]

Martin Honnen wrote:

You can however also pass in an object where the object is a W3C
DOM Node.

Thank you so much Martin, that actually fixed my problem! The following
code now works with and without a network connection:
---------------------------------
DocumentBuilder db =
DocumentBuilderFactory.newInstance().newDocumentBu ilder();
db.setEntityResolver(new UriTransform());
final String completePath = //file path
Document doc = db.parse(new File(completePath));
XPath xpath = XPathFactory.newInstance().newXPath();
final String expression = "//property";
DTMNodeList nodes = (DTMNodeList) xpath.evaluate(expression, doc,
XPathConstants.NODESET);
---------------------------------