Qt 5.9 | Qt XML Patterns | Recipes Example | querymainwindow.cpp Example File

Qt 5.9.3 Reference Documentation

# querymainwindow.cpp Example File

recipes/querymainwindow.cpp

      /****************************************************************************
      **
      ** Copyright (C) 2017 The Qt Company Ltd.
      ** Contact: https://www.qt.io/licensing/
      **
      ** This file is part of the examples of the Qt Toolkit.
      **
      ** $QT_BEGIN_LICENSE:BSD$
      ** Commercial License Usage
      ** Licensees holding valid commercial Qt licenses may use this file in
      ** accordance with the commercial license agreement provided with the
      ** Software or, alternatively, in accordance with the terms contained in
      ** a written agreement between you and The Qt Company. For licensing terms
      ** and conditions see https://www.qt.io/terms-conditions. For further
      ** information use the contact form at https://www.qt.io/contact-us.
      **
      ** BSD License Usage
      ** Alternatively, you may use this file under the terms of the BSD license
      ** as follows:
      **
      ** "Redistribution and use in source and binary forms, with or without
      ** modification, are permitted provided that the following conditions are
      ** met:
      **   * Redistributions of source code must retain the above copyright
      **     notice, this list of conditions and the following disclaimer.
      **   * Redistributions in binary form must reproduce the above copyright
      **     notice, this list of conditions and the following disclaimer in
      **     the documentation and/or other materials provided with the
      **     distribution.
      **   * Neither the name of The Qt Company Ltd nor the names of its
      **     contributors may be used to endorse or promote products derived
      **     from this software without specific prior written permission.
      **
      **
      ** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
      ** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
      ** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
      ** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
      ** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
      ** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
      ** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
      ** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
      ** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
      ** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
      ** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
      **
      ** $QT_END_LICENSE$
      **
      ****************************************************************************/

      #include <QMessageBox>
      #include <QFileDialog>
      #include <QtXmlPatterns>

      #include "querymainwindow.h"
      #include "xmlsyntaxhighlighter.h"

      QueryMainWindow::QueryMainWindow() : ui_defaultQueries(0)
      {
          setupUi(this);

          new XmlSyntaxHighlighter(findChild<QTextEdit*>("inputTextEdit")->document());
          new XmlSyntaxHighlighter(findChild<QTextEdit*>("outputTextEdit")->document());

          ui_defaultQueries = findChild<QComboBox*>("defaultQueries");
          QMetaObject::connectSlotsByName(this);
          connect(ui_defaultQueries, SIGNAL(currentIndexChanged(int)), SLOT(displayQuery(int)));

          loadInputFile();
          const QStringList queries(QDir(":/files/", "*.xq").entryList());
          int len = queries.count();
          for(int i = 0; i < len; ++i)
              ui_defaultQueries->addItem(queries.at(i));
          if (len > 0)
              displayQuery(0);
      }

      void QueryMainWindow::displayQuery(int index)
      {
          QFile queryFile(QString(":files/") + ui_defaultQueries->itemText(index));
          queryFile.open(QIODevice::ReadOnly);
          const QString query(QString::fromLatin1(queryFile.readAll()));
          findChild<QTextEdit*>("queryTextEdit")->setPlainText(query);

          evaluate(query);
      }

      void QueryMainWindow::loadInputFile()
      {
          QFile forView;
          forView.setFileName(":/files/cookbook.xml");
          if (!forView.open(QIODevice::ReadOnly)) {
              QMessageBox::information(this,
                  tr("Unable to open file"), forView.errorString());
              return;
          }

          QTextStream in(&forView);
          QString inputDocument = in.readAll();
          findChild<QTextEdit*>("inputTextEdit")->setPlainText(inputDocument);
      }

      void QueryMainWindow::evaluate(const QString &str)
      {
          QFile sourceDocument;
          sourceDocument.setFileName(":/files/cookbook.xml");
          sourceDocument.open(QIODevice::ReadOnly);

          QByteArray outArray;
          QBuffer buffer(&outArray);
          buffer.open(QIODevice::ReadWrite);

          QXmlQuery query;
          query.bindVariable("inputDocument", &sourceDocument);
          query.setQuery(str);
          if (!query.isValid())
              return;

          QXmlFormatter formatter(query, &buffer);
          if (!query.evaluateTo(&formatter))
              return;

          buffer.close();
          findChild<QTextEdit*>("outputTextEdit")->setPlainText(QString::fromUtf8(outArray.constData()));

      }