Hi Dmitri, will open the bug, try to solve it and commit the patch if i manage to :)
Simone Dmitri Plotnikov wrote: >Simone, > >Feel free to try out the proposed change. If it works (and does not break >anything else), let me know and I will be happy to incorporate it in the >JXPath codebase. > >Unfortunately, I am currently very busy on several other projects and don't >have time to investigate the issue myself. > >Thank you very much for your help. > >- Dmitri > >----- Original Message ---- >From: Simone Gianni <[EMAIL PROTECTED]> >To: Jakarta Commons Developers List <commons-dev@jakarta.apache.org> >Sent: Friday, July 28, 2006 6:03:29 AM >Subject: Re: JXPath, beans and the count function > >Hi Dmitri, >thanks for your answer. > >We currently made a work around to check ourselves if the path is >actually pointing to a collection (invoking the getValue() ) before >invoking the evaluation of a count(path). > >Amyway, we think this could be a bug in JXPath. In fact the count >function calls the expression.compute(context) which states in its >javadoc "Evaluates the expression. If the result is a node set, returns >the first element of the node set." .. so IIUC it will never actually >return a java.util.Collection. > >Wouldn't it be better to try to retrieve the simple value before, check >if it is a Collection, and if it's not proceed with the rest of the >actual code? It's not a suggestion, is a real question :) I've been >using JXPath for long time inside cocoon, but never examined the code in >depth. > >Regards, > >Simone > >Dmitri Plotnikov wrote: > > > >>Simone, >> >>Perhaps a custom extension function could be used instead of >>"count(list)" to resolve the issue. >> >>- Dmitri >> >>----- Original Message ----- From: "Simone Gianni" <[EMAIL PROTECTED]> >>To: <commons-dev@jakarta.apache.org> >>Sent: Thursday, July 27, 2006 1:47 PM >>Subject: JXPath, beans and the count function >> >> >> >> >>>Hi there, >>>we are developing paginated repeater for Cocoon. The cocoon repeaters >>>uses JXPath in their binding so that they can work on beans and XML >>>documents. >>> >>>The goal for us is to display a very long list of elements from a >>>collection not fetching the entire content of the collection. This is >>>expecially useful when the collection is backed by a persistence layer >>>like hibernate or similar, and you have a very big rowset (we are >>>testing on an application with a list with 11000 elements in it). >>> >>>Now, one key element for every pagination system is to retrieve the >>>total amount of items in the list. We tried to accomplish this with a >>>count(pathToList). Actually we have a bean having a getList method >>>returning a java.util.List instance, so we try count(list/*) , >>>count(list), count(list/something), and we would expect JXPath to call >>>getList().size(). This is quite critical, because the list >>>implementation knows how to retrieve the number of rows without actually >>>fetching all the rows from the underlying dataset. >>> >>>Unfortunately, what hapens is different. The >>>CoreFunction.functionCount() method does not recognize it as a >>>Collection, but as a EvalContext instead, and iterates on all the lines >>>to count the items (actually is the EvalContext.hasNext() method that >>>iterates on the entire collection). >>> >>>What's strange is that there is a check in CoreFunction.functionCount() >>>to see if a Collection is in place and eventually call the >>>Collection.size() method, but this seems like it's never happening. >>> >>>Could you please help us? Is it a JXPath bug or are we completely >>>missing something? >>> >>>TIA, regards, >>>Simone Gianni, >>>Matthias Epheser >>> >>>--------------------------------------------------------------------- >>>To unsubscribe, e-mail: [EMAIL PROTECTED] >>>For additional commands, e-mail: [EMAIL PROTECTED] >>> >>> >>> >>> >>> >>--------------------------------------------------------------------- >>To unsubscribe, e-mail: [EMAIL PROTECTED] >>For additional commands, e-mail: [EMAIL PROTECTED] >> >> >> -- Simone Gianni --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
