text: /* -*- mode: c++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
  
  /*
   Copyright (C) 2002, 2003 Ferdinando Ametrano
   Copyright (C) 2000, 2001, 2002, 2003 RiskMap srl
   Copyright (C) 2007 StatPro Italia srl
  
   This file is part of QuantLib, a free-software/open-source library
   for financial quantitative analysts and developers - http://quantlib.org/
  
   QuantLib is free software: you can redistribute it and/or modify it
   under the terms of the QuantLib license.  You should have received a
   copy of the license along with this program; if not, please email
   <quantlib-dev@lists.sf.net>. The license is also available online at
   <http://quantlib.org/license.shtml>.
  
   This program is distributed in the hope that it will be useful, but WITHOUT
   ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
   FOR A PARTICULAR PURPOSE.  See the license for more details.
  */
  
  /*! \file pricingengine.hpp
      \brief Base class for pricing engines
  */
  
  #ifndef quantlib_pricing_engine_hpp
  #define quantlib_pricing_engine_hpp
  
  #include <ql/patterns/observable.hpp>
  
  namespace QuantLib {
  
      //! interface for pricing engines
      class PricingEngine : public Observable {
        public:
          class arguments;
          class results;
          ~PricingEngine() override {}
          virtual arguments* getArguments() const = 0;
          virtual const results* getResults() const = 0;
          virtual void reset() = 0;
          virtual void calculate() const = 0;
      };
  
      class PricingEngine::arguments {
        public:
          virtual ~arguments() {}
          virtual void validate() const = 0;
      };
  
      class PricingEngine::results {
        public:
          virtual ~results() {}
          virtual void reset() = 0;
      };
  
  
      //! template base class for option pricing engines
      /*! Derived engines only need to implement
          the <tt>calculate()</tt> method.
      */
      template<class ArgumentsType, class ResultsType>
      class GenericEngine : public PricingEngine,
                            public Observer {
        public:
          PricingEngine::arguments* getArguments() const override { return &arguments_; }
          const PricingEngine::results* getResults() const override { return &results_; }
          void reset() override { results_.reset(); }
          void update() override { notifyObservers(); }
  
        protected:
          mutable ArgumentsType arguments_;
          mutable ResultsType results_;
      };
  
  }
  
  
  #endif
  