David Bertoni wrote: > >> 1. Can I use an XPath after its XPathConstructionContext is deleted? if >> not, >> can i use one global XPathConstructionContext to construct all my XPath >> objects? > > No. You can use a global XPathConstructionContext, but you will need to > serialize access to it if you are using multiple threads. > So I reckon I can have a global XPathConstructionContext and a global XPathProcessorImpl, and protect initXPath() with a mutex; destroy the XPaths only in the end.
David Bertoni wrote: > > > >> 2. What is the difference between XPathProcessor::initXPath and >> XPathProcessor::initMatchPattern ? > One creates an XPath instance from an XPath expression, and the other > creates an XPath instance from a match pattern, which is a limited > subset of XPath. > Thanks. I'll use initXPath(), then. David Bertoni wrote: > >> 3. Why does XPathEvaluator::evaluate calls reset() for its >> executionContext >> and XObjectFactory, and why does it sets the executionContext's >> EnvSupport, >> DOMSupport and XObjectFactory? What happens if I set it only once? >> (assuming there is one evaluator for each input document) > > It resets these for various reasons: > > 1. It resets the XPathExecutionContext and the XPathEnvSupport instance > because it doesn't make sense for state from one evaluation to leak into > another one. > Makes sense. David Bertoni wrote: > > > 2. It resets the XObjectFactory to prevent a large number of XObject > instances from accumulating. You can certainly change this if you want > to. For example, you might want to reset only after a certain number of > XPath expressions have been evaluated. This would mean you could keep a > number of evaluation results around between evaluations. The current > model forces the user to copy the result of the evaluation before > evaluating another expression. > > Let me rephrase to make sure I understand: XObjectFactory is one-per-thread, and when I reset it, it deletes all the XObject instances it had created. If I want to keep the instance after the reset, i need to copy it (using copy constructor, i presume) and keep it in another place. I guess I can use two factories: one for temporary results (which I reset frequently) and one for the results I need to keep. David Bertoni wrote: > > > Dave > > Thank you. -- View this message in context: http://www.nabble.com/Questions-about-XPATH-API-tp22303292p22323531.html Sent from the Xalan - C - Users mailing list archive at Nabble.com.
