berryListenerList.h

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/*===================================================================

BlueBerry Platform

Copyright (c) German Cancer Research Center,
Division of Medical and Biological Informatics.
All rights reserved.

This software is distributed WITHOUT ANY WARRANTY; without
even the implied warranty of MERCHANTABILITY or FITNESS FOR
A PARTICULAR PURPOSE.

See LICENSE.txt or http://www.mitk.org for details.

===================================================================*/

#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