PreFactory.hh

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#ifndef  PRE_FACTORY_HH
#define  PRE_FACTORY_HH

#include <map>
#include <string>

using namespace std;

//adapted from Terralib to OM Pre-analysis ( Missae DPI/INPE )

template <class T, class Arg>
class PreFactory
{
public:

    // Dictionary of factories (indexed by name)
  typedef map<string, PreFactory<T,Arg>* > PreFactoryMap; 

    // Returns the single instance of the factory dictionay
  static PreFactoryMap& instance ()
  { 
    static PreFactoryMap Fmap_;
    return Fmap_;
    
  } 
  
  // Normal Constructor
  PreFactory (const string& factoryName);

  virtual ~PreFactory() {}

  // Virtual constructor using name
  static T* make  ( string name, const Arg& arg );

protected:

  // Builds a new type (should be implemented by descendants)
    virtual T* build ( const Arg& arg ) = 0;

private:
  string  Fname_;
};

// Constructor 
template <class T, class Arg>
PreFactory<T,Arg>::PreFactory(const string& name):
  Fname_(name)
{
  PreFactory<T,Arg>::instance()[name] = this;
}
  
// Builds an object, based on the input parameters
template <class T, class Arg> 
T*
PreFactory<T,Arg>::make ( string name, const Arg& arg )
{
  // try to find the name on the factory dictionary
  typename PreFactoryMap::iterator i = PreFactory<T,Arg>::instance().find ( name );

  // Not found ?  
  if ( i == PreFactory<T,Arg>::instance().end() )
  {
    std::string msg = "PreFactory<T,Arg>::make( string name, const Arg& arg ): Not found the name on the factory\n";
    Log::instance()->error( msg.c_str() );
    throw InvalidParameterException( msg );
  }

  // Create an object, based on the input parameters
  return (*i).second->build ( arg );
  return 0;

} 

#endif