listen.h

[詳解]

/*************************************************************************//*
 *  (c) 2001-2018 oZ/acy. ALL RIGHTS RESERVED.
 */
#ifndef INC_THEMIS_LISTENER_H___
#define INC_THEMIS_LISTENER_H___

#include <list>
#include <algorithm>
#include <boost/utility.hpp>

namespace themis
{
  template<class E_> class Listener;
  template<class E_> class Talker;
}


template<class E_>
class themis::Listener : boost::noncopyable
{
  friend class themis::Talker<E_>;

private:
  themis::Talker<E_>* tkr_;

public:
  constexpr Listener() noexcept : tkr_(nullptr) {}

  virtual ~Listener()
  {
    if (tkr_)
      tkr_->remove(this);
  }

  virtual void update(const E_&) =0;

private:
  void setTalker__(themis::Talker<E_>* t)
  {
    if (tkr_)
      tkr_->remove(this);
    tkr_ = t;
  }

  void removeFromTalker__()
  {
    tkr_ = nullptr;
  }
};


template<class E_>
class themis::Talker : boost::noncopyable
{
private:
  std::list<themis::Listener<E_>*> lsns_; 

public:
  constexpr Talker() noexcept {}

  virtual ~Talker()
  {
    for (auto it = lsns_.begin(); it != lsns_.end(); it++)
      (*it)->removeFromTalker__();
  }


  void add(themis::Listener<E_>* lsn)
  {
    auto it = std::find(lsns_.begin(), lsns_.end(), lsn);
    if (it == lsns_.end()) {
      lsns_.push_back(lsn);
      lsn->addToTalker__(this);
    }
  }


  void remove(themis::Listener<E_>* lsn)
  {
    auto it = std::find(lsns_.begin(), lsns_.end(), lsn);
    if (it != lsns_.end())
    {
      (*it)->removeFromTalker__();
      lsns_.erase(it);
    }
  }

  void notify(const E_& e)
  {
    for (auto it = lsns_.begin(); it != lsns_.end(); it++)
      (*it)->update(e);
  }
};




#endif // INC_THEMIS_LISTENER_H___