/**
* Returns the number value of the first item selected by applying the wrapped XPath expression to
* the given context.
*
* @param context the element to use as context for evaluating the XPath expression.
* @return the number value of the first item selected by applying the wrapped XPath expression to
* the given context, <code>null</code> if no node was selected or the special value {@link
* java.lang.Double#NaN} (Not-a-Number) if the selected value can not be converted into a
* number value.
* @throws JDOMException if the XPath expression is invalid or its evaluation on the specified
* context failed.
*/
@Override
public Number numberValueOf(Object context) throws JDOMException {
try {
navigator.setContext(context);
return xPath.numberValueOf(context);
} catch (JaxenException ex1) {
throw new JDOMException(
"XPath error while evaluating \"" + xPath.toString() + "\": " + ex1.getMessage(), ex1);
} finally {
navigator.reset();
}
}
/**
* Evaluates the wrapped XPath expression and returns the first entry in the list of selected
* nodes (or atomics).
*
* @param context the node to use as context for evaluating the XPath expression.
* @return the first selected item, which may be of types: {@link Element}, {@link Attribute},
* {@link Text}, {@link CDATA}, {@link Comment}, {@link ProcessingInstruction}, Boolean,
* Double, String, or <code>null</code> if no item was selected.
* @throws JDOMException if the evaluation of the XPath expression on the specified context
* failed.
*/
@Override
public Object selectSingleNode(Object context) throws JDOMException {
try {
navigator.setContext(context);
return unWrapNS(xPath.selectSingleNode(context));
} catch (JaxenException ex1) {
throw new JDOMException(
"XPath error while evaluating \"" + xPath.toString() + "\": " + ex1.getMessage(), ex1);
} finally {
navigator.reset();
}
}
/**
* Adds a namespace definition to the list of namespaces known of this XPath expression.
*
* <p><strong>Note</strong>: In XPath, there is no such thing as a 'default namespace'. The empty
* prefix <b>always</b> resolves to the empty namespace URI.
*
* @param namespace the namespace.
*/
@Override
public void addNamespace(Namespace namespace) {
navigator.includeNamespace(namespace);
}