text: /****************************************************************************
  **
  ** This file is part of the Ponder library, formerly CAMP.
  **
  ** The MIT License (MIT)
  **
  ** Copyright (C) 2009-2014 TEGESO/TEGESOFT and/or its subsidiary(-ies) and mother company.
  ** Copyright (C) 2015-2018 Nick Trout.
  **
  ** Permission is hereby granted, free of charge, to any person obtaining a copy
  ** of this software and associated documentation files (the "Software"), to deal
  ** in the Software without restriction, including without limitation the rights
  ** to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  ** copies of the Software, and to permit persons to whom the Software is
  ** furnished to do so, subject to the following conditions:
  ** 
  ** The above copyright notice and this permission notice shall be included in
  ** all copies or substantial portions of the Software.
  ** 
  ** THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  ** IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  ** FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  ** AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  ** LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  ** OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  ** THE SOFTWARE.
  **
  ****************************************************************************/
  
  #pragma once
  #ifndef PONDER_PROPERTY_HPP
  #define PONDER_PROPERTY_HPP
  
  
  #include <ponder/value.hpp>
  
  namespace ponder
  {
  
  class ClassVisitor;
  
  /**
   * \brief Abstract representation of a property
   *
   * Properties are members of metaclasses. Their main purpose is to be get and/or set;
   * They also provide detailed informations about their type.
   *
   * \sa SimpleProperty, ArrayProperty, EnumProperty, ObjectProperty
   */
  class PONDER_API Property : public Type
  {
      PONDER__NON_COPYABLE(Property);
  public:
  
      /**
       * \brief Destructor
       */
      virtual ~Property();
  
      /**
       * \brief Get the name of the property
       *
       * \return Name of the property
       */
      IdReturn name() const;
  
      /**
       * \brief Get the type of the property
       *
       * \return Type of the property
       */
      ValueKind kind() const;
  
      /**
       * \brief Check if the property can be read
       *
       * \return True if the property can be read, false otherwise
       */
      virtual bool isReadable() const;
      
      /**
       * \brief Check if the property can be written
       *
       * \return True if the property can be written, false otherwise
       */
      virtual bool isWritable() const;
  
      /**
       * \brief Get the current value of the property for a given object
       *
       * \param object Object
       *
       * \return Value of the property
       *
       * \throw NullObject object is invalid
       * \throw ForbiddenRead property is not readable
       */
      Value get(const UserObject& object) const;
  
      /**
       * \brief Set the current value of the property for a given object
       *
       * \param object Object
       * \param value New value to assign to the property
       *
       * \throw NullObject \a object is invalid
       * \throw ForbiddenWrite property is not writable
       * \throw BadType \a value can't be converted to the property's type
       */
      void set(const UserObject& object, const Value& value) const;
  
      /**
       * \brief Accept the visitation of a ClassVisitor
       *
       * \param visitor Visitor to accept
       */
      virtual void accept(ClassVisitor& visitor) const;
  
  protected:
  
      template <typename T> friend class ClassBuilder;
      friend class UserObject;
  
      /**
       * \brief Construct the property from its description
       *
       * \param name Name of the property
       * \param type Type of the property
       */
      Property(IdRef name, ValueKind type);
  
      /**
       * \brief Do the actual reading of the value
       *
       * This function is a pure virtual which has to be implemented in derived classes.
       *
       * \param object Object
       *
       * \return Value of the property
       */
      virtual Value getValue(const UserObject& object) const = 0;
  
      /**
       * \brief Do the actual writing of the value
       *
       * This function is a pure virtual which has to be implemented in derived classes.
       *
       * \param object Object
       * \param value New value to assign to the property
       */
      virtual void setValue(const UserObject& object, const Value& value) const = 0;
  
  private:
  
      Id m_name; // Name of the property
      ValueKind m_type; // Type of the property
  };
  
  } // namespace ponder
  
  
  #endif // PONDER_PROPERTY_HPP
  