observer.h

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/******************************************************************************
The MIT License(MIT)

Embedded Template Library.

Copyright(c) 2014 jwellbelove

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******************************************************************************/

#ifndef __ETL_OBSERVER__
#define __ETL_OBSERVER__

//*****************************************************************************
//*****************************************************************************

#include <algorithm>
#include "vector.h"
#include "exception.h"

namespace etl
{
#ifdef ETL_THROW_EXCEPTIONS
  //***************************************************************************
  //***************************************************************************
  class observer_exception : public exception
  {
  public:

    observer_exception(const char* what)
      : exception(what)
    {
    }
  };

  //***************************************************************************
  //***************************************************************************
  class observer_list_full : public observer_exception
  {
  public:

    observer_list_full()
      : observer_exception("observer: list full")
    {
    }
  };
#endif

  //*********************************************************************
  //*********************************************************************
  template <typename TObserver, const size_t MAX_OBSERVERS>
  class observable
  {
  public:

    typedef size_t size_type;

    typedef etl::vector<TObserver*, MAX_OBSERVERS> Observer_List;

    //*****************************************************************
    //*****************************************************************
    void add_observer(TObserver& observer)
    {
          // See if we already have it in our list.
      typename Observer_List::const_iterator i_observer = std::find(observer_list.begin(),
                                                                    observer_list.end(),
                                                                    &observer);

          // Not there?
      if (i_observer == observer_list.end())
      {
        // Is there enough room?
        if (!observer_list.full())
        {
          // Add it.
          observer_list.push_back(&observer);
        }
#ifdef ETL_THROW_EXCEPTIONS
        else
        {
          throw observer_list_full();
        }
#endif
      }
    }

    //*****************************************************************
    //*****************************************************************
    void remove_observer(TObserver& observer)
    {
      // See if we have it in our list.
      typename Observer_List::iterator i_observer = std::find(observer_list.begin(),
                                                              observer_list.end(),
                                                              &observer);

      // Found it?
      if (i_observer != observer_list.end())
      {
        // Erase it.
        observer_list.erase(i_observer);
      }
    }

    //*****************************************************************
    //*****************************************************************
    void clear_observers()
    {
      observer_list.clear();
    }

    //*****************************************************************
    //*****************************************************************
    size_type number_of_observers() const
    {
      return observer_list.size();
    }

    //*****************************************************************
    //*****************************************************************
    template <typename TNotification>
    void notify_observers(TNotification n)
    {
      for (size_t i = 0; i < observer_list.size(); ++i)
      {
        observer_list[i]->notification(n);
      }
    }

  private:

    Observer_List observer_list;
  };

  //*********************************************************************
  //*********************************************************************
  template <typename T1,
            typename T2  = void,
            typename T3  = void,
            typename T4  = void,
            typename T5  = void,
            typename T6  = void,
            typename T7  = void,
            typename T8  = void>
  class observer
  {
  public:
    virtual ~observer() {}
    virtual void notification(T1) = 0;
    virtual void notification(T2) = 0;
    virtual void notification(T3) = 0;
    virtual void notification(T4) = 0;
    virtual void notification(T5) = 0;
    virtual void notification(T6) = 0;
    virtual void notification(T7) = 0;
    virtual void notification(T8) = 0;
  };

  //*********************************************************************
  //*********************************************************************
  template <typename T1,
            typename T2,
            typename T3,
            typename T4,
            typename T5,
            typename T6,
            typename T7>
  class observer<T1, T2, T3, T4, T5, T6, T7>
  {
  public:

    virtual ~observer() {}
    virtual void notification(T1) = 0;
    virtual void notification(T2) = 0;
    virtual void notification(T3) = 0;
    virtual void notification(T4) = 0;
    virtual void notification(T5) = 0;
    virtual void notification(T6) = 0;
    virtual void notification(T7) = 0;
  };

  //*********************************************************************
  //*********************************************************************
  template <typename T1,
            typename T2,
            typename T3,
            typename T4,
            typename T5,
            typename T6>
  class observer<T1, T2, T3, T4, T5, T6>
  {
  public:

    virtual ~observer() {}
    virtual void notification(T1) = 0;
    virtual void notification(T2) = 0;
    virtual void notification(T3) = 0;
    virtual void notification(T4) = 0;
    virtual void notification(T5) = 0;
    virtual void notification(T6) = 0;
  };

  //*********************************************************************
  //*********************************************************************
  template <typename T1,
            typename T2,
            typename T3,
            typename T4,
            typename T5>
  class observer<T1, T2, T3, T4, T5>
  {
  public:

    virtual ~observer() {}
    virtual void notification(T1) = 0;
    virtual void notification(T2) = 0;
    virtual void notification(T3) = 0;
    virtual void notification(T4) = 0;
    virtual void notification(T5) = 0;
  };

  //*********************************************************************
  //*********************************************************************
  template <typename T1,
            typename T2,
            typename T3,
            typename T4>
  class observer<T1, T2, T3, T4>
  {
  public:

    virtual ~observer() {}
    virtual void notification(T1) = 0;
    virtual void notification(T2) = 0;
    virtual void notification(T3) = 0;
    virtual void notification(T4) = 0;
  };

  //*********************************************************************
  //*********************************************************************
  template <typename T1,
            typename T2,
            typename T3>
  class observer<T1, T2, T3>
  {
  public:

    virtual ~observer() {}
    virtual void notification(T1) = 0;
    virtual void notification(T2) = 0;
    virtual void notification(T3) = 0;
  };

  //*********************************************************************
  //*********************************************************************
  template <typename T1,
            typename T2>
  class observer<T1, T2>
  {
  public:

    virtual ~observer() {}
    virtual void notification(T1) = 0;
    virtual void notification(T2) = 0;
  };

  //*********************************************************************
  //*********************************************************************
  template <typename T1>
  class observer<T1>
  {
  public:

    virtual ~observer() {}
    virtual void notification(T1) = 0;
  };
}

#endif