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  1. #include <iostream>
  2. #include <string>
  3. #include <map>
  4.  
  5. template<class ID,class Base,class ... Args> class GenericObjectFactory{
  6. private:
  7.     typedef Base* (*fInstantiator)(Args ...);
  8.     template<class Derived> static Base* instantiator(Args ... args){
  9.         return new Derived(args ...);
  10.     }
  11.     std::map<ID,fInstantiator> classes;
  12.  
  13. public:
  14.     GenericObjectFactory(){}
  15.     template<class Derived> void add(ID id){
  16.         classes[id]=&instantiator<Derived>;
  17.     }
  18.     fInstantiator get(ID id){
  19.         return classes[id];
  20.     }
  21.  
  22. };
  23.  
  24. using namespace std;
  25.  
  26. class Animal{
  27. public:
  28.     Animal(bool isAlive,string name) : isAlive(isAlive),name(name){};
  29.     bool isAlive;
  30.     string name;
  31.     virtual string voice() const=0;
  32. };
  33. class Dog : public Animal{
  34. public:
  35.     using Animal::Animal;
  36.     string voice() const{
  37.         return this->isAlive?
  38.             "Woof! I'm "+this->name+"\n":
  39.             "";
  40.     }
  41. };
  42. class Cat : public Animal{
  43. public:
  44.     using Animal::Animal;
  45.     string voice() const{
  46.     	return this->isAlive?
  47.             "Meow, I'm "+this->name+"\n":
  48.             "";
  49.     }
  50. };
  51.  
  52. int main(void){
  53.     GenericObjectFactory<string,Animal,bool,string> animalFactory;
  54.  
  55.     animalFactory.add<Dog>("man's friend");
  56.     animalFactory.add<Cat>("^_^");
  57.  
  58.     Animal *dog1=animalFactory.get("man's friend")(true,"charlie");
  59.     Animal *dog2=animalFactory.get("man's friend")(false,"fido");
  60.     Animal *cat =animalFactory.get("^_^")(true,"begemoth");
  61.  
  62.     cout << dog1->voice()
  63.          << dog2->voice()
  64.          << cat ->voice();
  65.     return 0;
  66. }
  67.  
Success #stdin #stdout 0s 3436KB
comments (?)
stdin 
Standard input is empty
stdout 
Woof! I'm charlie
Meow, I'm begemoth
https://ideone.com/5D5Fz1
A cool factory boilerplate with usage example. (ru: http://h...content-available-to-author-only...r.ru/post/229993/)
language:
C++14 (gcc 8.3)
created:
10 years ago
visibility:
public

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