/**
* Return the XPathContext to be used for evaluating expressions.
*
* <p>If the child is nested withing a forEach tag its iteration context is used. Otherwise, a new
* context is created based on an empty Document.
*
* @param child the tag whose context should be returned
* @param pageContext the current page context
* @return the XPath evaluation context
*/
public static XPathContext getContext(Tag child, PageContext pageContext) {
// if within a forEach tag, use its context
ForEachTag forEachTag = (ForEachTag) TagSupport.findAncestorWithClass(child, ForEachTag.class);
if (forEachTag != null) {
return forEachTag.getContext();
}
// otherwise, create a new context referring to an empty document
XPathContext context = new XPathContext(false);
VariableStack variableStack = new JSTLVariableStack(pageContext);
context.setVarStack(variableStack);
int dtm = context.getDTMHandleFromNode(newEmptyDocument());
context.pushCurrentNodeAndExpression(dtm, dtm);
return context;
}
