c++ dom parser problem - c++

Question

I want to change an XML file. I'm using DOM Parser. My XML file is the following:
<?xml version="1.0"?>
<?xml-stylesheet type="text/xsl" href="configuration.xsl"?>
<!-- Put site-specific property overrides in this file. -->
<configuration>
<property>
<name>fs.default.name</name>
<value> name</value>
</property>
</configuration>
I just want to remove the <value>name</name> node and put a new node <value>next</value>. How can I do this?
I wrote code in C++ also, but I'm stuck in the middle. What should I do? My code is the following:
#include<string.h>
#include<iostream>
#include<sstream>
#include<sys/types.h>
#include<unistd.h>
#include<errno.h>
#include<sys/stat.h>
#include "parser.hpp"
using namespace xercesc ;
using namespace std;
GetConfig::GetConfig()
{
XMLPlatformUtils::Initialize();
TAG_configuration =XMLString::transcode("configuration");
TAG_property = XMLString::transcode("property");
TAG_value=XMLString::transcode("value");
Tag_name=XMLString::transcode("name");
m_ConfigFileParser=new XercesDOMParser;
}
GetConfig::~GetConfig()
{
delete m_ConfigFileParser;
XMLString::release( &TAG_configuration );
XMLString::release( &TAG_property );
XMLString::release( &TAG_value );
XMLPlatformUtils::Terminate();
}
void GetConfig :: readConfigFile(string& configFile)
{
struct stat fileStatus;
int iretStat = stat(configFile.c_str(), &fileStatus);
if( iretStat == ENOENT )
throw ( std::runtime_error("Path file_name does not exist, or path is an empty string.") );
else if( iretStat == ENOTDIR )
throw ( std::runtime_error("A component of the path is not a directory."));
else if( iretStat == ELOOP )
throw ( std::runtime_error("Too many symbolic links encountered while traversing the path."));
else if( iretStat == EACCES )
throw ( std::runtime_error("Permission denied."));
else if( iretStat == ENAMETOOLONG )
throw ( std::runtime_error("File can not be read\n"));
// Configure DOM parser.
m_ConfigFileParser->setValidationScheme( XercesDOMParser::Val_Never );
m_ConfigFileParser->setDoNamespaces( false );
m_ConfigFileParser->setDoSchema( false );
m_ConfigFileParser->setLoadExternalDTD( false );
m_ConfigFileParser->parse( configFile.c_str() );
DOMDocument* xmlDoc = m_ConfigFileParser->getDocument();
DOMElement* elementRoot = xmlDoc->getDocumentElement();
DOMNodeList* children = elementRoot->getChildNodes();
int main()
{
string configFile="/home/manish.yadav/Desktop/simple.xml";
GetConfig appConfig;
appConfig.readConfigFile(configFile);
return 0;
}
Now I don't know how to traverse this document. Here are my questions:
How can I reach to <value>?
How can I change value of <value> name</value> to <value> next</value>?
My idea is to remove the entity and then add it again with different value, but I don't know how to do this, either. Please explain with example code, or suggest any other ideas on how to do this.

Answer 1

After m_ConfigFileParser->parse( configFile.c_str() ); do the following (considering "configuration" is the root element):
DOMDocument* doc = m_ConfigFileParser.getDocument();
DOMElement* root = dynamic_cast<DOMElement*>( doc->getFirstChild() );
if ( root ) {
DOMElement* property = dynamic_cast<DOMElement*>( root->getElementsByTagName( "property" )->item( 0 ) );
if ( property ) {
DOMElement* value = dynamic_cast<DOMElement*>( property->getElementsByTagName( "value" )->item( 0 ) );
if ( value ) {
value->setTextContent( " next" ); // this will update the element named "value"
}
}
}