template <typename T>
class Queue
{
public:

  using Type = T;
  using OptionalType = boost::optional<T>;

  ~Queue()
  {
    std::lock_guard<std::mutex> l(mMutex);
  }

  void push(const T& obj)
  {
    std::lock_guard<std::mutex> l(mMutex);

    mData.push_back(obj);
  }

  void push(T&& obj)
  {
    std::lock_guard<std::mutex> l(mMutex);

    mData.push_back(std::move(obj));
  }

  bool pop(T& obj)
  {
    std::lock_guard<std::mutex> l(mMutex);

    if (mData.empty())
    {
      return false;
    }
    else
    {
      obj = std::move(mData.front());
      mData.pop_front();
      return true;
    }
  }

  OptionalType pop()
  {
    std::lock_guard<std::mutex> l(mMutex);
    OptionalType result;

    if (!mData.empty())
    {
      result = std::move(mData.front());
      mData.pop_front();
    }

    return result;
  }

private:

  std::deque<T> mData;
  std::mutex mMutex;
};