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#include "Singleton.hpp"
#include <string>
#include <iostream>
using namespace std;
class Logger : public Singleton< Logger >
{
public:
DECLARE_SINGLETON( Logger )
void log( string s )
{
cout << s << endl;
}
friend class Singleton< Logger >;
protected:
Logger( )
{
cout << "Logger created" << endl;
}
public:
~Logger( )
{
cout << "Logger destroyed" << endl;
}
};
/* this works, and two loggers can coexist, but they have different type
class DerivedLogger : public Logger
{
public:
void log( string s )
{
cout << "derived " << s << endl;
}
};
*/
class X : public Singleton< X >
{
public:
void doSomething( )
{
logger.log( "X is doing something" );
}
friend class Singleton< X >;
protected:
X ( ) : logger( Singleton< Logger >::instance( ) )
{
logger.log( "Creating singleton X" );
}
public:
~X( )
{
logger.log( "Destroying singleton X" );
}
private:
Logger &logger;
};
void f( )
{
Logger &logger = Singleton< Logger >::instance( );
logger.log( "bla" );
}
int main( void )
{
f( );
X &x = Singleton< X >::instance( );
x.doSomething( );
// this would copy the object, noncopyable ensure we have
// only a private copy cnostructor
//Logger l1 = Singleton< Logger >::instance( );
// Logger anotherOne; this doesn't work, as expected
// DerivedLogger anotherOne; the same here
// see explanation above
//DerivedLogger &l2 = Singleton< DerivedLogger >::instance( );
//l2.log( "blu" );
// we can't accidently destroy the logger
//delete &logger;
return 0;
}
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