Comments by Andy Rama (Top 5 by date)

Hi Aescleal and all,

Thanks for reply.

Considering that my question is not understandable, below I am explaining it again.
I wanted to design a class or library for parsing any xml-file, named as CXmlParser. This class will have a function ParseXml() to perform actual xml-file parsing. Along with it another class, CXmlTag, to store every xml-tag data.

An external module/application, class name as CExternalCaller, will use above mentioned class/library to parse any xml-file.

CExternalCaller will call ParseXml() of CXmlParser.
Then CXmlParser will do the parsing. But code/action for start-tag and end-tag will not be residing in CXmlParser class.
Instead of that external module i.e. CExternalCaller should decide that behaviour. So any other module/application using same parsing (CXmlParser) can have different behaviour.

This was my problem definition. Interface implementation for CXmlParser (CXmlParser class with pure virtual function) can be one of the solution for it.
But I was trying to implement it using member-function-pointers (for StartTag & EndTag indication) in CXmlParser class which will store addresses of respective functions of caller, i.e. CExternalCaller. There were many problems when I was trying to implement this solution.

Thanks Aescleal, I took help from your post & implement it using template and function-pointer as follows.

//XmlParser
class CXmlParser
{
public :
template<class caller="">
void ParseXml(const string& rsXmlFile, CALLER* pCaller, void (CALLER::*pfStartTag)(CXmlTag* pTag), void (CALLER::*pfEndTag)(CXmlTag* pTag) );
};

template<class caller="">
void CXmlReader::ParseXml(const string& rsXmlFile, CALLER* pCaller, void (CALLER::*pfStartTag)(CXmlTag* pTag), void (CALLER::*pfEndTag)(CXmlTag* pTag) )
{
.....
CXmlTag* pXmlTag = new CXmlTag();
.....
//START OF XML-TAG
if( pCaller && pfStartTag )
(pCaller->*pfStartTag)(pXmlTag);
.....
//END OF XML-TAG
if( pCaller && pfEndTag )
(pCaller->*pfEndTag)(pXmlTag);
.....
}



//ExternalCaller
class CExternalCaller
{
public :
void GetData()
{
....
//READ DATA FROM XML
CXmlParser xmlParser;
xmlParser.ParseXml("<xml-file-path>", this, &CExternalCaller::StartTag, &CExternalCaller::EndTag);
....
}

private :
void StartTag(CXmlTag* pTag) {}
void EndTag(CXmlTag* pTag) {}
};


Atleast now its working as per my requirement. Please let me know if I am wrong anywhere in problem definition or approach.

Thanks & Regards,
Aniket