I am trying to get an Element via the XPathExpression option from JDOM.
My code looks like this:
public static Element getElement(Document doc)
{
XPathFactory xpfac = XPathFactory.instance();
XPathExpression<Element> xp = xpfac.compile("//uml:Model/packagedElement[@name='Content']", Filters.element());
return xp.evaluateFirst(doc);
}
Sadly i get the following error:
java.lang.IllegalArgumentException: Namespace with prefix 'uml' has not been declared.
My document starts like this:
<?xml version='1.0' encoding='UTF-8'?>
<xmi:XMI xmi:version='2.1' xmlns:uml='http://www.omg.org/spec/UML/20090901'...
So in my opinion the namespace is declared. If i check the xpath expression with a tool for the given document, the element is found.
Thats how i created the document:
public static Document readXML(File file)
{
Document doc = null;
try {
doc = new SAXBuilder().build(file);
} catch (JDOMException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return doc;
}
So, wheres the error? How can the XpathExpression find the element "//uml:Model/packagedElement[@name='Content']" ?
Best regards
The namespace is declared in the XML, but you also have to register it for the XPath query .
XPathExpression<Element> xp =
xpfac.compile("//uml:Model/packagedElement[@name='Content']",
Filters.element(),
null,
Namespace.getNamespace("uml", "http://www.omg.org/spec/UML/20090901"));
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