//
  // FIFOStrategy.h
  //
  // $Id:\; //poco/1.3/Foundation/include/Poco/FIFOStrategy.h\#5$
  //
  // Library: Foundation
  // Package: Events
  // Module:  FIFOStragegy
  //
  // Implementation of the FIFOStrategy template.
  //
  // Copyright (c) 2006, Applied Informatics Software Engineering GmbH.
  // and Contributors.
  //
  // Permission is hereby granted, free of charge, to any person or organization
  // obtaining a copy of the software and accompanying documentation covered by
  // this license (the "Software") to use, reproduce, display, distribute,
  // execute, and transmit the Software, and to prepare derivative works of the
  // Software, and to permit third-parties to whom the Software is furnished to
  // do so, all subject to the following:
  // 
  // The copyright notices in the Software and this entire statement, including
  // the above license grant, this restriction and the following disclaimer,
  // must be included in all copies of the Software, in whole or in part, and
  // all derivative works of the Software, unless such copies or derivative
  // works are solely in the form of machine-executable object code generated by
  // a source language processor.
  // 
  // 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, TITLE AND NON-INFRINGEMENT. IN NO EVENT
  // SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
  // FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
  // ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  // DEALINGS IN THE SOFTWARE.
  //
  
  ifndef  Foundation_FIFOStrategy_INCLUDED
  define  Foundation_FIFOStrategy_INCLUDED
  
  include "Poco/NotificationStrategy.h"
  include <map>
  include <list>
  include <memory>
  
  namespace Poco {
  
  template <class TArgs, class TDelegate, class TCompare> 
  class FIFOStrategy: public NotificationStrategy<TArgs, TDelegate>
  {
  public:
          typedef std::list<TDelegate*>                    Delegates;
          typedef typename Delegates::iterator             Iterator;
          typedef typename Delegates::const_iterator       ConstIterator;
          typedef std::map<TDelegate*, Iterator, TCompare> DelegateIndex;
          typedef typename DelegateIndex::iterator         IndexIterator;
          typedef typename DelegateIndex::const_iterator   ConstIndexIterator;
  
          FIFOStrategy()
          {
          }
  
          FIFOStrategy(const FIFOStrategy& s)
          {
                  operator = (s);
          }
  
          ~FIFOStrategy()
          {
                  clear();
          }
  
          void notify(const void* sender, TArgs& arguments)
          {
                  std::vector<Iterator> delMe;
                  Iterator it    = _observers.begin();
                  Iterator itEnd = _observers.end();
  
                  for (; it != itEnd; ++it)
                  {
                          if (!(*it)->notify(sender, arguments))
                          {
                                  // schedule for deletion
                                  delMe.push_back(it);
                          }
                  }
                  
                  while (!delMe.empty())
                  {
                          typename std::vector<Iterator>::iterator vit = delMe.end();
                          --vit;
                          delete **vit;
                          _observers.erase(*vit);
                          delMe.pop_back();
                  }
          }
  
          void add(const TDelegate& delegate)
          {
                  IndexIterator it = _observerIndex.find(const_cast<TDelegate*>(&delegate));
                  if (it != _observerIndex.end())
                  {
                          delete *it->second;
                          _observers.erase(it->second);
                          _observerIndex.erase(it);
                  }
                  std::auto_ptr<TDelegate> pDelegate(delegate.clone());
                  _observers.push_back(pDelegate.get());
                  bool tmp = _observerIndex.insert(std::make_pair(pDelegate.get(), --_observers.end())).second;
                  poco_assert (tmp);
                  pDelegate.release();
          }
  
          void remove(const TDelegate& delegate)
          {
                  IndexIterator it = _observerIndex.find(const_cast<TDelegate*>(&delegate));
  
                  if (it != _observerIndex.end())
                  {
                          delete *it->second;
                          _observers.erase(it->second);
                          _observerIndex.erase(it);
                  }
          }
  
          FIFOStrategy& operator = (const FIFOStrategy& s)
          {
                  if (this != &s)
                  {
                          for (ConstIterator it = s._observers.begin(); it != s._observers.end(); ++it)
                          {
                                  add(**it);
                          }
                  }
                  return *this;
          }
  
          void clear()
          {
                  for (Iterator it = _observers.begin(); it != _observers.end(); ++it)
                  {
                          delete *it;
                  }
  
                  _observers.clear();
                  _observerIndex.clear();
          }
  
          bool empty() const
          {
                  return _observers.empty();
          }
  
  protected:
          Delegates     _observers;     
 Stores the delegates in the order they were added.
          DelegateIndex _observerIndex; 
 For faster lookup when add/remove is used.
  };
  
  } // namespace Poco
  
  endif