--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/doc/src/snippets/persistentindexes/model.cpp	Mon Jan 11 14:00:40 2010 +0000
@@ -0,0 +1,169 @@
+/****************************************************************************
+**
+** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
+** All rights reserved.
+** Contact: Nokia Corporation (qt-info@nokia.com)
+**
+** This file is part of the documentation of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** No Commercial Usage
+** This file contains pre-release code and may not be distributed.
+** You may use this file in accordance with the terms and conditions
+** contained in the Technology Preview License Agreement accompanying
+** this package.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU Lesser General Public License version 2.1 requirements
+** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Nokia gives you certain additional
+** rights.  These rights are described in the Nokia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** If you have questions regarding the use of this file, please contact
+** Nokia at qt-info@nokia.com.
+**
+**
+**
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+/*
+  model.cpp
+
+  A simple model that uses a QStringList as its data source.
+*/
+
+#include <qdebug.h>
+
+#include "model.h"
+
+/*!
+    Returns the number of items in the string list as the number of rows
+    in the model.
+*/
+
+int StringListModel::rowCount(const QModelIndex &parent) const
+{
+    return stringList.count();
+}
+
+/*!
+    Returns an appropriate value for the requested data.
+    If the view requests an invalid index, an invalid variant is returned.
+    If a header is requested then we just return the column or row number,
+    depending on the orientation of the header.
+    Any valid index that corresponds to a string in the list causes that
+    string to be returned.
+*/
+
+QVariant StringListModel::data(const QModelIndex &index, int role) const
+{
+    if (!index.isValid())
+        return QVariant();
+
+    if (index.row() < 0 || index.row() >= stringList.size())
+        return QVariant();
+
+    if (role == Qt::DisplayRole)
+        return stringList.at(index.row());
+    else
+        return QVariant();
+}
+
+/*!
+    Returns the appropriate header string depending on the orientation of
+    the header and the section. If anything other than the display role is
+    requested, we return an invalid variant.
+*/
+
+QVariant StringListModel::headerData(int section, Qt::Orientation orientation,
+                                     int role) const
+{
+    if (role != Qt::DisplayRole)
+        return QVariant();
+
+    if (orientation == Qt::Horizontal)
+        return QString("Column %1").arg(section);
+    else
+        return QString("Row %1").arg(section);
+}
+
+/*!
+    Returns an appropriate value for the item's flags. Valid items are
+    enabled, selectable, and editable.
+*/
+
+Qt::ItemFlags StringListModel::flags(const QModelIndex &index) const
+{
+    if (!index.isValid())
+        return Qt::ItemIsEnabled;
+
+    return QAbstractItemModel::flags(index) | Qt::ItemIsEditable;
+}
+
+/*!
+    Changes an item in the string list, but only if the following conditions
+    are met:
+
+    * The index supplied is valid.
+    * The index corresponds to an item to be shown in a view.
+    * The role associated with editing text is specified.
+
+    The dataChanged() signal is emitted if the item is changed.
+*/
+
+bool StringListModel::setData(const QModelIndex &index,
+                              const QVariant &value, int role)
+{
+    if (index.isValid() && role == Qt::EditRole) {
+
+        stringList.replace(index.row(), value.toString());
+        emit dataChanged(index, index);
+        return true;
+    }
+    return false;
+}
+
+/*!
+    Inserts a number of rows into the model at the specified position.
+*/
+
+bool StringListModel::insertRows(int position, int rows, const QModelIndex &parent)
+{
+    beginInsertRows(parent, position, position + rows - 1);
+
+    for (int row = 0; row < rows; ++row) {
+        stringList.insert(position, "");
+    }
+
+    endInsertRows();
+    return true;
+}
+
+/*!
+    Removes a number of rows from the model at the specified position.
+*/
+
+bool StringListModel::removeRows(int position, int rows, const QModelIndex &parent)
+{
+    beginRemoveRows(parent, position, position + rows - 1);
+
+    for (int row = 0; row < rows; ++row) {
+        stringList.removeAt(position);
+    }
+
+    endRemoveRows();
+    return true;
+}