Observer.hh

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#ifndef INCLUDED_ObjexxFCL_Observer_hh
#define INCLUDED_ObjexxFCL_Observer_hh


// Observer: Combined Subject + Observer Abstract Base Class
//
// Project: Objexx Fortran Compatibility Library (ObjexxFCL)
//
// Version: 3.0.0
//
// Language: C++
//
// Copyright (c) 2000-2009 Objexx Engineering, Inc. All Rights Reserved.
// Use of this source code or any derivative of it is restricted by license.
// Licensing is available from Objexx Engineering, Inc.:  http://objexx.com  Objexx@objexx.com


// ObjexxFCL Headers
#include <ObjexxFCL/Observer.fwd.hh>


namespace ObjexxFCL {


/// @brief Observer: Combined Subject + Observer Abstract Base Class
class Observer
{


protected: // Creation


  /// @brief Default Constructor
  inline
  Observer()
  {}


  /// @brief Copy Constructor
  inline
  Observer( Observer const & )
  {}


public: // Creation


  /// @brief Destructor
  inline
  virtual
  ~Observer()
  {}


protected: // Assignment


  /// @brief Copy Assignment
  inline
  Observer &
  operator =( Observer const & )
  {
    return *this;
  }


public: // Subject Inspector


  /// @brief Insert an Observer
  virtual
  void
  insert_observer( Observer & ) const = 0;


  /// @brief Remove an Observer
  virtual
  void
  remove_observer( Observer & ) const = 0;


  /// @brief Has At Least One Observer?
  virtual
  bool
  has_observer() const = 0;


  /// @brief Notify Observers That This Subject Has Changed
  void
  notify() const;


  /// @brief Acyclic After Adding an Observer of This Subject?
  bool
  acyclic( Observer & ) const;


public: // Observer Modifier


  /// @brief Update
  virtual
  void
  update() = 0;


  /// @brief Update for Destruction of a Subject
  virtual
  void
  destructed( Subject const & ) = 0;


}; // Observer


} // namespace ObjexxFCL


#endif // INCLUDED_ObjexxFCL_Observer_HH