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/*
SPDX-FileCopyrightText: 2011 Aaron Seigo <aseigo@kde.org>
SPDX-License-Identifier: BSD-2-Clause
*/
#include "sourcesOnRequest.h"
#include <Plasma/DataContainer>
#include <QStandardItemModel>
/*
This DataEngine shows how to created sources on demand as they are requested
and update them on visualization-requested update intervals.
It also shows how to bind and arbitrary QAbstractItemModel to a source
*/
SourcesOnRequestEngine::SourcesOnRequestEngine(QObject *parent, const QVariantList &args)
: Plasma::DataEngine(parent, args)
{
// We've passed the constructor's args to our parent class.
// We're done for now!
}
bool SourcesOnRequestEngine::sourceRequestEvent(const QString &source)
{
// When this method is called we can assume that:
// * the source does not exist yet
// * the source name parameter passed in is not an empty string
// * we are free to reject creating the source if we wish
// We're going to reject any sources that start with the letter 'a'
// to demonstrate how to reject a request in a DataEngine.
if (source.startsWith(QLatin1Char('a')) || source.startsWith(QLatin1Char('A'))) {
return false;
}
// For every other source, we're going to start an update count for it.
// Critically, we create a source before returning that has the exact
// same key as the source string. We MUST NOT create a source of a different
// name as that will cause unexpected results for the visualization.
// In such a case the DataEngine will remain happy and Do The Right Thing(tm)
// but the visualization will not get the source connected to it as it
// expects. So ALWAYS key the new data by the source string as below:
setData(source, QStringLiteral("Update Count"), 0);
if (!modelForSource(source)) {
QStandardItemModel *m = new QStandardItemModel;
m->appendRow(new QStandardItem(QStringLiteral("Item1, first update")));
m->appendRow(new QStandardItem(QStringLiteral("Item2, first update")));
m->appendRow(new QStandardItem(QStringLiteral("Item3, first update")));
setModel(source, m);
}
// as we successfully set up the source, return true
return true;
}
bool SourcesOnRequestEngine::updateSourceEvent(const QString &source)
{
// Whenever a visualization has requested an update, such as when passing
// an update interval to DataEngine::connectSource, this method will be called.
// When this method is called we can assume that:
// * the source exists
// * it hasn't been updated more frequently than the minimum update interval
//
// If not data is set in this method, then the update is skipped for the visualiation
// and that is just fine.
//
// We can also set data for other sources here if we wish, but as with
// sourceRequestEvent this may not be what the visualization expects. Unlike in
// sourceRequestEvent, however, this will result in expected behavior: visualizations
// connected to the sources which have setData called for them will be notified
// of these changes.
const int updateCount = containerForSource(source)->data().value(QStringLiteral("Update Count")).toInt() + 1;
setData(source, QStringLiteral("Update Count"), updateCount);
QStandardItemModel *m = qobject_cast<QStandardItemModel *>(modelForSource(source));
if (m) {
m->clear();
m->appendRow(new QStandardItem(QStringLiteral("Item1, update %1").arg(updateCount)));
m->appendRow(new QStandardItem(QStringLiteral("Item2, update %1").arg(updateCount)));
m->appendRow(new QStandardItem(QStringLiteral("Item3, update %1").arg(updateCount)));
}
// Since we updated the source immediately here, we need to return true so the DataEngine
// knows to continue with the update notification for visualizations.
return true;
}
// export the plugin; use the plugin name and the class name
K_PLUGIN_CLASS_WITH_JSON(SourcesOnRequestEngine, "plasma-dataengine-example-sourcesOnRequest.json")
// include the moc file so the build system makes it for us
#include "sourcesOnRequest.moc"
#include "moc_sourcesOnRequest.cpp"
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