@Override
    public final Object getValueAt(final int rowIndex, final int columnIndex) {
        final Vector<Entry<Program, Integer>> entries = data;

        if (rowIndex >= entries.size()) {
            return null;
        }

        final Entry<Program, Integer> entry = entries.get(rowIndex);

        if (columnIndex == 0) {
            return entry.getValue();
        } else {
            return entry.getKey();
        }
    }