97 lines
4.3 KiB
C++
97 lines
4.3 KiB
C++
/*
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* Copyright 2011 Aaron Seigo <aseigo@kde.org>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include "sourcesOnRequest.h"
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#include <Plasma/DataContainer>
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/*
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This DataEngine shows how to created sources on demand as they are requested
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and update them on visualization-requested update intervals.
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*/
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SourcesOnRequestEngine::SourcesOnRequestEngine(QObject *parent, const QVariantList &args)
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: Plasma::DataEngine(parent, args)
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{
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// We've passed the constructor's args to our parent class.
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// We're done for now!
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}
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bool SourcesOnRequestEngine::sourceRequestEvent(const QString &source)
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{
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// When this method is called we can assume that:
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// * the source does not exist yet
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// * the source name parameter passed in is not an empty string
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// * we are free to reject creating the source if we wish
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// We're going to reject any sources that start with the letter 'a'
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// to demonstrate how to reject a request in a DataEngine.
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if (source.startsWith('a') || source.startsWith('A')) {
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return false;
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}
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// For every other source, we're going to start an update count for it.
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// Critically, we create a source before returning that has the exact
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// same key as the source string. We MUST NOT create a source of a different
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// name as that will cause unexpected results for the visualization.
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// In such a case the DataEngine will remain happy and Do The Right Thing(tm)
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// but the visualization will not get the source connected to it as it
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// expects. So ALWAYS key the new data by the source string as below:
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setData(source, "Update Count", 0);
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// as we successfully set up the source, return true
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return true;
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}
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bool SourcesOnRequestEngine::updateSourceEvent(const QString &source)
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{
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// Whenever a visualization has requested an update, such as when passing
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// an update interval to DataEngine::connectSource, this method will be called.
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// When this method is called we can assume that:
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// * the source exists
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// * it hasn't been updated more frequently than the minimum update interval
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//
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// If not data is set in this method, then the update is skipped for the visualiation
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// and that is just fine.
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//
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// We can also set data for other sources here if we wish, but as with
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// sourceRequestEvent this may not be what the visualization expects. Unlike in
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// sourceRequestEvent, however, this will result in expected behavior: visualizations
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// connected to the sources which have setData called for them will be notified
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// of these changes.
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setData(source, "Update Count", containerForSource(source)->data().value("Update Count").toInt() + 1);
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// Since we updated the source immediately here, we need to return true so the DataEngine
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// knows to continue with the update notification for visualizations.
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return true;
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}
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// export the plugin; use the plugin name and the class name
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K_EXPORT_PLASMA_DATAENGINE_WITH_JSON(org.kde.examples.sourcesOnRequest, SourcesOnRequestEngine, "plasma-dataengine-example-sourcesOnRequest.json")
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// include the moc file so the build system makes it for us
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#include "sourcesOnRequest.moc"
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