berryListenerList.h

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/*============================================================================
 
The Medical Imaging Interaction Toolkit (MITK)
 
Copyright (c) German Cancer Research Center (DKFZ)
All rights reserved.
 
Use of this source code is governed by a 3-clause BSD license that can be
found in the LICENSE file.
 
============================================================================*/
 
#ifndef BERRYLISTENERLIST_H
#define BERRYLISTENERLIST_H
 
#include <QMutex>
#include <QList>
#include <QReadWriteLock>
 
namespace berry {
 
struct ListenerListEquals
{
  template<class T>
  bool operator()(const T& l1, const T& l2) const
  {
    return l1 == l2;
  }
};
 
template<class T, typename C = ListenerListEquals>
class ListenerList
{
 
public:
 
  void Add(const T& listener)
  {
    // This method is synchronized to protect against multiple threads adding
    // or removing listeners concurrently.
 
    // check for duplicates
    QWriteLocker l(&mutex);
    const int oldSize = listeners.size();
    for (int i = 0; i < oldSize; ++i)
    {
      T& listener2 = listeners[i];
      if (comparator(listener, listener2))
        return;
    }
 
    listeners.push_back(listener);
  }
 
  QList<T> GetListeners() const
  {
    QReadLocker l(&mutex);
    return listeners;
  }
 
  bool IsEmpty() const
  {
    QReadLocker l(&mutex);
    return listeners.empty();
  }
 
  void Remove(const T &listener)
  {
    QWriteLocker l(&mutex);
    // This method is synchronized to protect against multiple threads adding
    // or removing listeners concurrently.
    const int oldSize = listeners.size();
    for (int i = 0; i < oldSize; ++i)
    {
      T& listener2 = listeners[i];
      if (comparator(listener, listener2))
      {
        listeners.removeAt(i);
        return;
      }
    }
  }
 
  int Size() const
  {
    QReadLocker l(&mutex);
    return listeners.size();
  }
 
  void Clear()
  {
    QWriteLocker l(&mutex);
    listeners.clear();
  }
 
private:
 
  QList<T> listeners;
 
  mutable QReadWriteLock mutex;
 
  C comparator;
};
 
}
 
#endif // BERRYLISTENERLIST_H