Serialization arbitary data types

[amiref]

Hi
I wrote a program ( that will come below ) that has 2 class with names : keyNode and valueNode and every class has 2 private member . now I create QMap<keyNode , valueNode > and I want to serialize this QMap with QDataStream and I know that I must override operator<<() and operator>>() but I dont know how . please help me .
thanks

#include <QMap>
#include <QString>
#include <conio.h>
#include <QFile>
#include <QDataStream>
#include <QIODevice>
#include <QtCore/QCoreApplication>
 
 
class valueNode
{
public:
	valueNode() 
	{
		docId = 0 ;
		termFreq = 0 ;
	}
	valueNode( qint32 doc , qint32 term )
	{
		docId = doc ;
		termFreq = term ;
	}
	void setDocId( qint32 newDocId ) 
	{
		docId = newDocId ;
	}
	void setTermFreq( qint32 newTermFreq ) 
	{
		termFreq = newTermFreq ;
	}
	qint32 getDocId() const
	{	
		return docId ;
	}
	qint32 getTermFreq() const 
	{
		return termFreq ;
	}
 
private:
	qint32 docId ;
	qint32 termFreq ;
};
 
 
class keyNode
{
public:
	keyNode() 
	{
 
		docFreq = 0 ;
	}
	keyNode( QString k , qint32 doc )
	{
		key = k ;
		docFreq = doc ;
	}
	void setKey( QString newKey ) 
	{
		key = newKey ;
	}
	void setDFreocq( qint32 newDocFreq ) 
	{
		docFreq = newDocFreq ;
	}
	QString  getKey() const 
	{	
		return key ;
	}
	qint32 getDocFreq() const 
	{
		return docFreq ;
	}
 
private:
	QString key ;
	qint32 docFreq ;
};
 
 
 
inline bool operator<(const keyNode &e1, const keyNode &e2)
 {
	 return e1.getKey() < e2.getKey() ;
 }
 
 
 
int main(int argc, char *argv[])
{
	QCoreApplication a(argc, argv);
 
	QMap< keyNode , valueNode >  map ;
	QMap< QString , valueNode > mmap ;
 
	map[ keyNode( "school" , 18 ) ] = valueNode( 12 , 17 ) ;
	map[ keyNode( "class" , 45 ) ] = valueNode( 122 , 76 ) ;
	map[ keyNode( "student" , 23 ) ] = valueNode( 1 , 5 ) ;
	map[ keyNode( "amir" , 32 ) ] = valueNode( 187 , 58 ) ;
	map[ keyNode( "xoom" , 179 ) ] = valueNode( 139 , 25 ) ;
	map[ keyNode( "class" , 1115 ) ] = valueNode( 1002 , 876 ) ;
 
	mmap[ "v" ] = valueNode( 11 , 12 ) ;
	mmap[ "a" ] = valueNode( 112 , 3022 ) ;
	mmap[ "c" ] = valueNode( 91 , 762 ) ;
	mmap[ "x" ] = valueNode( 654 , 102 ) ;
 
	 QFile file("file.dat");
	 file.open(QIODevice::WriteOnly);
	 QDataStream out(&file);   // we will serialize the data into the file
	 out << map  ;   // serialize a string
	 file.close() ;
	 map.clear() ;
 
 
	file.open(QIODevice::ReadOnly);
	QDataStream in(&file);    // read the data serialized from the file
	in >> map;  
	file.close() ;
	getch() ;
	return a.exec();
}

#include <QMap>
#include <QString>
#include <conio.h>
#include <QFile>
#include <QDataStream>
#include <QIODevice>
#include <QtCore/QCoreApplication>


class valueNode
{
public:
	valueNode() 
	{
		docId = 0 ;
		termFreq = 0 ;
	}
	valueNode( qint32 doc , qint32 term )
	{
		docId = doc ;
		termFreq = term ;
	}
	void setDocId( qint32 newDocId ) 
	{
		docId = newDocId ;
	}
	void setTermFreq( qint32 newTermFreq ) 
	{
		termFreq = newTermFreq ;
	}
	qint32 getDocId() const
	{	
		return docId ;
	}
	qint32 getTermFreq() const 
	{
		return termFreq ;
	}

private:
	qint32 docId ;
	qint32 termFreq ;
};


class keyNode
{
public:
	keyNode() 
	{
		
		docFreq = 0 ;
	}
	keyNode( QString k , qint32 doc )
	{
		key = k ;
		docFreq = doc ;
	}
	void setKey( QString newKey ) 
	{
		key = newKey ;
	}
	void setDFreocq( qint32 newDocFreq ) 
	{
		docFreq = newDocFreq ;
	}
	QString  getKey() const 
	{	
		return key ;
	}
	qint32 getDocFreq() const 
	{
		return docFreq ;
	}

private:
	QString key ;
	qint32 docFreq ;
};



inline bool operator<(const keyNode &e1, const keyNode &e2)
 {
	 return e1.getKey() < e2.getKey() ;
 }



int main(int argc, char *argv[])
{
	QCoreApplication a(argc, argv);

	QMap< keyNode , valueNode >  map ;
	QMap< QString , valueNode > mmap ;

	map[ keyNode( "school" , 18 ) ] = valueNode( 12 , 17 ) ;
	map[ keyNode( "class" , 45 ) ] = valueNode( 122 , 76 ) ;
	map[ keyNode( "student" , 23 ) ] = valueNode( 1 , 5 ) ;
	map[ keyNode( "amir" , 32 ) ] = valueNode( 187 , 58 ) ;
	map[ keyNode( "xoom" , 179 ) ] = valueNode( 139 , 25 ) ;
	map[ keyNode( "class" , 1115 ) ] = valueNode( 1002 , 876 ) ;
	
	mmap[ "v" ] = valueNode( 11 , 12 ) ;
	mmap[ "a" ] = valueNode( 112 , 3022 ) ;
	mmap[ "c" ] = valueNode( 91 , 762 ) ;
	mmap[ "x" ] = valueNode( 654 , 102 ) ;

	 QFile file("file.dat");
	 file.open(QIODevice::WriteOnly);
	 QDataStream out(&file);   // we will serialize the data into the file
	 out << map  ;   // serialize a string
	 file.close() ;
	 map.clear() ;


	file.open(QIODevice::ReadOnly);
	QDataStream in(&file);    // read the data serialized from the file
	in >> map;  
	file.close() ;
	getch() ;
	return a.exec();
}

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[JohannesMunk]

Hi!

You will have to implement these functions (see http://doc.qt.nokia.com/4.7/qdatastr...her-qt-classes)

QDataStream & operator<< (QDataStream& stream, const keyNode& key)
{
  // break down the composite class to primitives and stream it..
  stream << key.getKey() << key.getDocFreq();
  return stream;
}
QDataStream & operator>> (QDataStream& stream, keyNode& key)
{
  QString keyS;qint32 docFreq;
  stream >> keyS >> docFreq;
  key.setKey(keyS);
  key.setDFreocq(docFreq);
  return stream;
}
QDataStream & operator<< (QDataStream& stream, const valueNode& value);
QDataStream & operator>> (QDataStream& stream, valueNode& value);

QDataStream & operator<< (QDataStream& stream, const keyNode& key)
{
  // break down the composite class to primitives and stream it..
  stream << key.getKey() << key.getDocFreq();
  return stream;
}
QDataStream & operator>> (QDataStream& stream, keyNode& key)
{
  QString keyS;qint32 docFreq;
  stream >> keyS >> docFreq;
  key.setKey(keyS);
  key.setDFreocq(docFreq);
  return stream;
}
QDataStream & operator<< (QDataStream& stream, const valueNode& value);
QDataStream & operator>> (QDataStream& stream, valueNode& value);

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You could also use the private fields instead of the accessor-functions but then you need to declare the operators as friends to the class.

HIH

Joh