Yes it throws.
It is handled by your fatalError which then re-throws it to .. your "unknown
error" catch.
I don't know much about exception handling- in fact I avoid using them when I
can.
Instead, I install a DOMErrorHandler and then gather messages until after the
parse. But that's me.
I use a single DOMLSParser which lasts for the duration of the process, and
then I let it manage the documents as it likes.
So my normal approach is to use my own 'loadDocument' method which deals with
the parsing and returns a DOMDocument, or a NULL
Here is a simple example, which actually comes from a bug report.
#include <iostream>
#include <sstream>
#include <xercesc/dom/DOM.hpp>
using namespace xercesc;
using namespace std;
class myErrorHandler : public DOMErrorHandler {
ostringstream errors;
public:
bool handleError(const xercesc::DOMError& domError) {
char* msg = XMLString::transcode(domError.getMessage());
errors << "[" << msg << "]";
XMLString::release(&msg);
return true;
}
void errs(string& result) {
result = errors.str();
errors.str("");
}
myErrorHandler() : DOMErrorHandler() {}
};
int main(int argc, char *argv[]) {
const XMLCh ls_id [] = {chLatin_L, chLatin_S, chNull};
XMLPlatformUtils::Initialize();
myErrorHandler* errorHandler = new myErrorHandler();
DOMImplementation* impl
(DOMImplementationRegistry::getDOMImplementation (ls_id));
DOMLSParser* xmlParser = impl->createLSParser
(DOMImplementationLS::MODE_SYNCHRONOUS,NULL);
DOMConfiguration* conf (xmlParser->getDomConfig ());
conf->setParameter(XMLUni::fgDOMErrorHandler,errorHandler);
conf->setParameter(XMLUni::fgXercesCacheGrammarFromParse,true);
conf->setParameter(XMLUni::fgXercesUseCachedGrammarInParse,true);
conf->setParameter(XMLUni::fgXercesSchema,true);
conf->setParameter(XMLUni::fgXercesIgnoreCachedDTD,false);
conf->setParameter(XMLUni::fgDOMValidate,true);
DOMDocument *foo = NULL;
xmlParser->loadGrammar("foo.xsd",Grammar::SchemaGrammarType,true);
foo = xmlParser->parseURI("foo.xml");
string err;
errorHandler->errs(err);
cout << "Errors for foo.xml:" << err << endl;
XMLPlatformUtils::Terminate();
return 0;
}
Adding memory inputsource is a bit more tricky - but I do it something like
this:
const XMLCh *mem = {chLatin_M, chLatin_E, chLatin_M, chNull};
std::string xmlfile = "<? xml version="1.0" ?><bla bla bla />" ;
DOMDocument *foo = NULL;
DOMLSInput *input = ((DOMImplementationLS*)impl)->createLSInput();
XMLByte *xmlraw = (XMLByte*)(xmlfile.c_str());
MemBufInputSource *mbis = new MemBufInputSource(xmlraw,xmlfile.size(),mem);
mbis->setCopyBufToStream(false);
input->setByteStream(mbis);
input->setEncoding(XMLUni::fgUTF8EncodingString);
try {
foo = parser->parse(input);
} catch (...); //deal with parser throws here!
input->release();
I cannot say that eny of this is the right way to do things, but maybe it's of
some use to you?
Lots of people use SAX instead of DOM, which depends upon your purpose of
course.
Not really sure that any of this helps.
I am really STILL LEARNING xercesc after five years. Just ask Alberto how
annoying I can be at times :D
> Well, yeah, I am just learning the basics :-)
>
> But I figured that deleting the XercesDOMParser and returning the DOMDocument
> would be wrong, because the XercesDOMParser owns the DOMDocument, no?
>
> -Patrick
>
> P.S.
> Did running my "broken" code on your machine trigger the catch(...) or the
> catch(const SAXException& e)?
>
> On May 18, 2010, at 7:08 AM, Ben Griffin wrote:
>
>> I had a look at your 'broken' source.
>> There was no main function, so I added one in as follows:
>>
>> int main() {
>> XMLPlatformUtils::Initialize();
>> XercesDOMParser* parser = ParseXML("input");
>> return 0;
>> }
>>
>> I commented out the QK:: push stuff, because it's not part of the library
>> (that I know of).
>>
>> I added
>> #include <xercesc/parsers/XercesDOMParser.hpp>
>>
>> I don't have / don't use util.hpp so I added
>> namespace {
>> typedef std::basic_string<XMLCh> XercesString;
>> }
>>
>> Regardless, I have sent you the source code directly.
>> It compiles and runs.
>>
>> I don't really know why you would want to return the parser having parsed a
>> file. Normally one wants the document from the parse.
>> Maybe you are just getting the basics up first...!
>>
>>
>> On 18 May 2010, at 12:01, Patrick Rutkowski wrote:
>>
>>> If any of you Xerces-C devs are up for it, I would be willing to go as far
>>> as doing a screen-sharing session to debug this, since it seems to be
>>> impossible to reproduce. I have my version of xerces already built with -g
>>> -O0 even.
>>>
>>> Of course, that might amount to you helping me find a silly big in my code
>>> somewhere, free of charge, which might seem unfair. Then again, maybe it
>>> really is an obscure bug in Xerces, which would make it worth it.
>>>
>>> I dunno, I just don't know what to do anymore :-/
>>>
>>> -Patrick
>>>
>>> On May 18, 2010, at 2:47 AM, Vitaly Prapirny wrote:
>>>
>>>> Patrick Rutkowski wrote:
>>>>> I have verified with test prints and gdb that fatalError()
>>>>> in ThrowErrorHandler is indeed triggered like it's supposed
>>>>> to be, so we're good so far.
>>>>
>>>> So the parser->setErrorHandler() is not broken actually, your subject
>>>> line misleads. I could assume your toolchain or project is
>>>> somewhat broken. If you could prepare a minimal self-contained test case
>>>> it would be very helpfull to someone who wished to look at it.
>>>>
>>>> Good luck!
>>>> Vitaly
>>>
>>
>
