+ virtual QModelIndex index(int row, int col, const QModelIndex &parent) const;
+ virtual QModelIndex parent(const QModelIndex &index) const;
+ virtual int rowCount(const QModelIndex &) const;
+ virtual int columnCount(const QModelIndex &) const;
+ virtual QVariant data(const QModelIndex &, int role) const;
+ virtual QVariant headerData(int section, Qt::Orientation orientation, int role = Qt::DisplayRole) const;