Plasma::DataEngine

#include <Plasma/DataEngine>

Inheritance diagram for Plasma::DataEngine:

Public Types
typedef QMap< QString, QVariant >	Data

typedef QMapIterator< QString, QVariant >	DataIterator

typedef QHash< QString, DataEngine * >	Dict

typedef QHash< QString, DataContainer * >	SourceDict

Signals
void	sourceAdded (const QString &source)

void	sourceRemoved (const QString &source)

Public Member Functions
	DataEngine (const KPluginInfo &plugin, QObject *parent=nullptr)

	DataEngine (const KPluginMetaData &plugin, QObject *parent=nullptr)

	DataEngine (QObject *parent=nullptr, const QVariantList &args=QVariantList())

Q_INVOKABLE void	connectAllSources (QObject *visualization, uint pollingInterval=0, Plasma::Types::IntervalAlignment intervalAlignment=Types::NoAlignment) const

Q_INVOKABLE void	connectSource (const QString &source, QObject *visualization, uint pollingInterval=0, Plasma::Types::IntervalAlignment intervalAlignment=Types::NoAlignment) const

Q_INVOKABLE DataContainer *	containerForSource (const QString &source)

Q_INVOKABLE void	disconnectSource (const QString &source, QObject *visualization) const

bool	isEmpty () const

bool	isValid () const

KPluginMetaData	metadata () const

QAbstractItemModel *	modelForSource (const QString &source)

Package	package () const

KPluginInfo	pluginInfo () const

virtual Q_INVOKABLE Service *	serviceForSource (const QString &source)

virtual QStringList	sources () const

Public Member Functions inherited from QObject
	QObject (QObject *parent)

bool	blockSignals (bool block)

const QObjectList &	children () const const

QMetaObject::Connection	connect (const QObject sender, const char signal, const char *method, Qt::ConnectionType type) const const

void	deleteLater ()

void	destroyed (QObject *obj)

bool	disconnect (const char signal, const QObject receiver, const char *method) const const

bool	disconnect (const QObject receiver, const char method) const const

void	dumpObjectInfo ()

void	dumpObjectInfo () const const

void	dumpObjectTree ()

void	dumpObjectTree () const const

QList< QByteArray >	dynamicPropertyNames () const const

virtual bool	event (QEvent *e)

virtual bool	eventFilter (QObject watched, QEvent event)

T	findChild (const QString &name, Qt::FindChildOptions options) const const

QList< T >	findChildren (const QRegExp &regExp, Qt::FindChildOptions options) const const

QList< T >	findChildren (const QRegularExpression &re, Qt::FindChildOptions options) const const

QList< T >	findChildren (const QString &name, Qt::FindChildOptions options) const const

bool	inherits (const char *className) const const

void	installEventFilter (QObject *filterObj)

bool	isWidgetType () const const

bool	isWindowType () const const

void	killTimer (int id)

virtual const QMetaObject *	metaObject () const const

void	moveToThread (QThread *targetThread)

QString	objectName () const const

void	objectNameChanged (const QString &objectName)

QObject *	parent () const const

QVariant	property (const char *name) const const

	Q_CLASSINFO (Name, Value)

	Q_DISABLE_COPY (Class)

	Q_DISABLE_COPY_MOVE (Class)

	Q_DISABLE_MOVE (Class)

	Q_EMIT Q_EMIT

	Q_ENUM (...)

	Q_ENUM_NS (...)

	Q_ENUMS (...)

	Q_FLAG (...)

	Q_FLAG_NS (...)

	Q_FLAGS (...)

	Q_GADGET Q_GADGET

	Q_INTERFACES (...)

	Q_INVOKABLE Q_INVOKABLE

	Q_NAMESPACE Q_NAMESPACE

	Q_NAMESPACE_EXPORT (EXPORT_MACRO)

	Q_OBJECT Q_OBJECT

	Q_PROPERTY (...)

	Q_REVISION Q_REVISION

	Q_SET_OBJECT_NAME (Object)

	Q_SIGNAL Q_SIGNAL

	Q_SIGNALS Q_SIGNALS

	Q_SLOT Q_SLOT

	Q_SLOTS Q_SLOTS

T	qFindChild (const QObject *obj, const QString &name)

QList< T >	qFindChildren (const QObject *obj, const QRegExp &regExp)

QList< T >	qFindChildren (const QObject *obj, const QString &name)

T	qobject_cast (const QObject *object)

T	qobject_cast (QObject *object)

	QT_NO_NARROWING_CONVERSIONS_IN_CONNECT QT_NO_NARROWING_CONVERSIONS_IN_CONNECT

void	removeEventFilter (QObject *obj)

void	setObjectName (const QString &name)

void	setParent (QObject *parent)

bool	setProperty (const char *name, const QVariant &value)

bool	signalsBlocked () const const

int	startTimer (int interval, Qt::TimerType timerType)

int	startTimer (std::chrono::milliseconds time, Qt::TimerType timerType)

QThread *	thread () const const

Protected Slots
void	forceImmediateUpdateOfAllVisualizations ()

void	removeSource (const QString &source)

void	updateAllSources ()

Protected Member Functions
void	addSource (DataContainer *source)

QHash< QString, DataContainer * >	containerDict () const

int	minimumPollingInterval () const

void	removeAllData (const QString &source)

void	removeAllSources ()

void	removeData (const QString &source, const QString &key)

void	setData (const QString &source, const QString &key, const QVariant &value)

void	setData (const QString &source, const QVariant &value)

void	setData (const QString &source, const QVariantMap &data)

void	setMinimumPollingInterval (int minimumMs)

void	setModel (const QString &source, QAbstractItemModel *model)

void	setPollingInterval (uint frequency)

void	setStorageEnabled (const QString &source, bool store)

void	setValid (bool valid)

virtual bool	sourceRequestEvent (const QString &source)

void	timerEvent (QTimerEvent *event) override

virtual bool	updateSourceEvent (const QString &source)

Protected Member Functions inherited from QObject
virtual void	childEvent (QChildEvent *event)

virtual void	connectNotify (const QMetaMethod &signal)

virtual void	customEvent (QEvent *event)

virtual void	disconnectNotify (const QMetaMethod &signal)

bool	isSignalConnected (const QMetaMethod &signal) const const

int	receivers (const char *signal) const const

QObject *	sender () const const

int	senderSignalIndex () const const

Additional Inherited Members
Properties inherited from QObject
	objectName

Static Public Member Functions inherited from QObject
QMetaObject::Connection	connect (const QObject sender, const char signal, const QObject receiver, const char method, Qt::ConnectionType type)

QMetaObject::Connection	connect (const QObject sender, const QMetaMethod &signal, const QObject receiver, const QMetaMethod &method, Qt::ConnectionType type)

QMetaObject::Connection	connect (const QObject sender, PointerToMemberFunction signal, const QObject context, Functor functor, Qt::ConnectionType type)

QMetaObject::Connection	connect (const QObject sender, PointerToMemberFunction signal, const QObject receiver, PointerToMemberFunction method, Qt::ConnectionType type)

QMetaObject::Connection	connect (const QObject *sender, PointerToMemberFunction signal, Functor functor)

bool	disconnect (const QMetaObject::Connection &connection)

bool	disconnect (const QObject sender, const char signal, const QObject receiver, const char method)

bool	disconnect (const QObject sender, const QMetaMethod &signal, const QObject receiver, const QMetaMethod &method)

bool	disconnect (const QObject sender, PointerToMemberFunction signal, const QObject receiver, PointerToMemberFunction method)

QString	tr (const char sourceText, const char disambiguation, int n)

QString	trUtf8 (const char sourceText, const char disambiguation, int n)

Public Attributes inherited from QObject
typedef	QObjectList

Detailed Description

Data provider for plasmoids (Plasma plugins)

This is the base class for DataEngines, which provide access to bodies of data via a common and consistent interface. The common use of a DataEngine is to provide data to a widget for display. This allows a user interface element to show all sorts of data: as long as there is a DataEngine, the data is retrievable.

DataEngines are loaded as plugins on demand and provide zero, one or more data sources which are identified by name. For instance, a network DataEngine might provide a data source for each network interface.

Definition at line 50 of file dataengine.h.

Constructor & Destructor Documentation

◆ DataEngine() [1/2]

Plasma::DataEngine::DataEngine	(	const KPluginInfo &	plugin,
		QObject *	parent = `nullptr`
	)

explicit

Constructor.

Parameters

parent	The parent object.
plugin	plugin info that describes the engine

Deprecated:: since 5.67

Definition at line 36 of file dataengine.cpp.

◆ DataEngine() [2/2]

Plasma::DataEngine::DataEngine	(	const KPluginMetaData &	plugin,
		QObject *	parent = `nullptr`
	)

explicit

Constructor.

Parameters

parent	The parent object.
plugin	metadata that describes the engine

Since: 5.67

Definition at line 42 of file dataengine.cpp.

Member Function Documentation

◆ addSource()

void Plasma::DataEngine::addSource ( DataContainer * source )

protected

Adds an already constructed data source.

The DataEngine takes ownership of the DataContainer object. The objectName of the source is used for the source name.

Parameters

source the DataContainer to add to the DataEngine

Definition at line 256 of file dataengine.cpp.

◆ connectAllSources()

void Plasma::DataEngine::connectAllSources	(	QObject *	visualization,
		uint	pollingInterval = `0`,
		Plasma::Types::IntervalAlignment	intervalAlignment = `Types::NoAlignment`
	)		const

Connects all currently existing sources to an object for data updates.

The object must have a slot with the following signature:

void dataUpdated(const QString &sourceName, const Plasma::DataEngine::Data &data);

The data is a QHash of QVariants keyed by QString names, allowing one data source to provide sets of related data.

This method may be called multiple times for the same visualization without side-effects. This can be useful to change the pollingInterval.

Note that this method does not automatically connect sources that may appear later on. Connecting and responding to the sourceAdded signal is still required to achieve that.

Parameters

visualization	the object to connect the data source to
pollingInterval	the frequency, in milliseconds, with which to check for updates; a value of 0 (the default) means to update only when there is new data spontaneously generated (e.g. by the engine); any other value results in periodic updates from this source. This value is per-visualization and can be handy for items that require constant updates such as scrolling graphs or clocks. If the data has not changed, no update will be sent.
intervalAlignment	the number of ms to align the interval to

Definition at line 127 of file dataengine.cpp.

◆ connectSource()

void Plasma::DataEngine::connectSource	(	const QString &	source,
		QObject *	visualization,
		uint	pollingInterval = `0`,
		Plasma::Types::IntervalAlignment	intervalAlignment = `Types::NoAlignment`
	)		const

Connects a source to an object for data updates.

The object must have a slot with the following signature:

void dataUpdated(const QString &sourceName, const Plasma::DataEngine::Data &data);

The data is a QHash of QVariants keyed by QString names, allowing one data source to provide sets of related data.

Parameters

source	the name of the data source
visualization	the object to connect the data source to
pollingInterval	the frequency, in milliseconds, with which to check for updates; a value of 0 (the default) means to update only when there is new data spontaneously generated (e.g. by the engine); any other value results in periodic updates from this source. This value is per-visualization and can be handy for items that require constant updates such as scrolling graphs or clocks. If the data has not changed, no update will be sent.
intervalAlignment	the number of ms to align the interval to

Definition at line 108 of file dataengine.cpp.

◆ containerDict()

QHash< QString, DataContainer * > Plasma::DataEngine::containerDict ( ) const

protected

Returns: the list of active DataContainers.

Definition at line 334 of file dataengine.cpp.

◆ containerForSource()

DataContainer * Plasma::DataEngine::containerForSource ( const QString & source )

Retrieves a pointer to the DataContainer for a given source.

This method should not be used if possible. An exception is for script engines that can not provide a QMetaObject as required by connectSource for the initial call to dataUpdated. Using this method, such engines can provide their own connectSource API.

Parameters

source the name of the source.

Returns: pointer to a DataContainer, or zero on failure

Definition at line 143 of file dataengine.cpp.

◆ disconnectSource()

void Plasma::DataEngine::disconnectSource	(	const QString &	source,
		QObject *	visualization
	)		const

Disconnects a source from an object that was receiving data updates.

Parameters

source	the name of the data source
visualization	the object to connect the data source to

Definition at line 134 of file dataengine.cpp.

◆ forceImmediateUpdateOfAllVisualizations

void Plasma::DataEngine::forceImmediateUpdateOfAllVisualizations ( )

protectedslot

Forces an immediate update to all connected sources, even those with timeouts that haven't yet expired.

This should only be used when there was no data available, e.g. due to network non-availability, and then it becomes available. Normal changes in data values due to calls to updateSource or in the natural progression of the monitored object (e.g. CPU heat) should not result in a call to this method!

Since: 4.4

Definition at line 385 of file dataengine.cpp.

◆ isEmpty()

bool Plasma::DataEngine::isEmpty ( ) const

Returns true if the data engine is empty, which is to say that it has no data sources currently.

Returns: true if the engine has no sources currently

Definition at line 324 of file dataengine.cpp.

◆ isValid()

bool Plasma::DataEngine::isValid ( ) const

Returns true if this engine is valid, otherwise returns false.

Returns: true if the engine is valid

Definition at line 319 of file dataengine.cpp.

◆ metadata()

KPluginMetaData Plasma::DataEngine::metadata ( ) const

Returns: description of the plugin that implements this DataEngine

Since: 5.67

Definition at line 103 of file dataengine.cpp.

◆ minimumPollingInterval()

int Plasma::DataEngine::minimumPollingInterval ( ) const

protected

Returns: the minimum time between updates.

See also: setMinimumPollingInterval

Definition at line 277 of file dataengine.cpp.

◆ modelForSource()

QAbstractItemModel * Plasma::DataEngine::modelForSource ( const QString & source )

Returns: The model associated to a source if any. The ownership of the model stays with the DataContainer. Returns 0 if there isn't any model associated or if the source doesn't exists.

Definition at line 245 of file dataengine.cpp.

◆ package()

Package Plasma::DataEngine::package ( ) const

Accessor for the associated Package object if any.

Returns: the Package object, or 0 if none

Definition at line 394 of file dataengine.cpp.

◆ pluginInfo()

KPluginInfo Plasma::DataEngine::pluginInfo ( ) const

Returns: description of the plugin that implements this DataEngine

Deprecated:: since 5.67, use metadata

Definition at line 97 of file dataengine.cpp.

◆ removeAllData()

void Plasma::DataEngine::removeAllData ( const QString & source )

protected

Removes all the data associated with a data source.

Parameters

source the name of the data source

Definition at line 212 of file dataengine.cpp.

◆ removeAllSources()

void Plasma::DataEngine::removeAllSources ( )

protected

Removes all data sources.

Definition at line 305 of file dataengine.cpp.

◆ removeData()

void Plasma::DataEngine::removeData	(	const QString &	source,
		const QString &	key
	)

protected

Removes a data entry from a source.

Parameters

source	the name of the data source
key	the data entry to remove

Definition at line 221 of file dataengine.cpp.

◆ removeSource

void Plasma::DataEngine::removeSource ( const QString & source )

protectedslot

Removes a data source.

Parameters

source the name of the data source to remove

Definition at line 292 of file dataengine.cpp.

◆ serviceForSource()

Service * Plasma::DataEngine::serviceForSource ( const QString & source )

virtual

Parameters

source the source to target the Service at

Returns: a Service that has the source as a destination. The service is parented to the DataEngine, but should be deleted by the caller when finished with it

Definition at line 84 of file dataengine.cpp.

◆ setData() [1/3]

void Plasma::DataEngine::setData	(	const QString &	source,
		const QString &	key,
		const QVariant &	value
	)

protected

Sets a value for a data source.

If the source doesn't exist then it is created.

Parameters

source	the name of the data source
key	the key to use for the data
value	the data to associated with the source

Definition at line 172 of file dataengine.cpp.

◆ setData() [2/3]

void Plasma::DataEngine::setData	(	const QString &	source,
		const QVariant &	value
	)

protected

Sets a value for a data source.

If the source doesn't exist then it is created.

Parameters

source	the name of the data source
value	the data to associated with the source

Definition at line 167 of file dataengine.cpp.

◆ setData() [3/3]

void Plasma::DataEngine::setData	(	const QString &	source,
		const QVariantMap &	data
	)

protected

Adds a set of data to a data source.

If the source doesn't exist then it is created.

Parameters

source	the name of the data source
data	the data to add to the source

Definition at line 190 of file dataengine.cpp.

◆ setMinimumPollingInterval()

void Plasma::DataEngine::setMinimumPollingInterval ( int minimumMs )

protected

Sets the minimum amount of time, in milliseconds, that must pass between successive updates of data.

This can help prevent too many updates happening due to multiple update requests coming in, which can be useful for expensive (time- or resource-wise) update mechanisms.

The default minimumPollingInterval is -1, or "never perform automatic updates"

Parameters

minimumMs the minimum time lapse, in milliseconds, between updates. A value less than 0 means to never perform automatic updates, a value of 0 means update immediately on every update request, a value >0 will result in a minimum time lapse being enforced.

Definition at line 272 of file dataengine.cpp.

◆ setModel()

void Plasma::DataEngine::setModel	(	const QString &	source,
		QAbstractItemModel *	model
	)

protected

Associates a model to a data source.

If the source doesn't exist then it is created. The source will have the key "HasModel" to easily indicate there is a model present.

The ownership of the model is transferred to the DataContainer, so the model will be deleted when a new one is set or when the DataContainer itself is deleted. As the DataContainer, it will be deleted when there won't be any visualization associated to this source.

Parameters

source	the name of the data source
model	the model instance

Definition at line 230 of file dataengine.cpp.

◆ setPollingInterval()

void Plasma::DataEngine::setPollingInterval ( uint frequency )

protected

Sets up an internal update tick for all data sources.

On every update, updateSourceEvent will be called for each applicable source.

See also: updateSourceEvent

Parameters

frequency the time, in milliseconds, between updates. A value of 0 will stop internally triggered updates.

Definition at line 282 of file dataengine.cpp.

◆ setStorageEnabled()

void Plasma::DataEngine::setStorageEnabled	(	const QString &	source,
		bool	store
	)

protected

Sets a source to be stored for easy retrieval when the real source of the data (usually a network connection) is unavailable.

Parameters

source	the name of the source
store	if source should be stored

Since: 4.6

Definition at line 400 of file dataengine.cpp.

◆ setValid()

void Plasma::DataEngine::setValid ( bool valid )

protected

Sets whether or not this engine is valid, e.g.

can be used. In practice, only the internal fall-back engine, the NullEngine should have need for this.

Parameters

valid whether or not the engine is valid

Definition at line 329 of file dataengine.cpp.

◆ sourceAdded

void Plasma::DataEngine::sourceAdded ( const QString & source )

signal

Emitted when a new data source is created.

Note that you do not need to emit this yourself unless you are reimplementing sources() and want to advertise that a new source is available (but hasn't been created yet).

Parameters

source the name of the new data source

◆ sourceRemoved

void Plasma::DataEngine::sourceRemoved ( const QString & source )

signal

Emitted when a data source is removed.

Note that you do not need to emit this yourself unless you have reimplemented sources() and want to signal that a source that was available but was never created is no longer available.

Parameters

source the name of the data source that was removed

◆ sourceRequestEvent()

bool Plasma::DataEngine::sourceRequestEvent ( const QString & source )

protectedvirtual

When a source that does not currently exist is requested by the consumer, this method is called to give the DataEngine the opportunity to create one.

The name of the data source (e.g. the source parameter passed into setData) must be the same as the name passed to sourceRequestEvent otherwise the requesting visualization may not receive notice of a data update.

If the source can not be populated with data immediately (e.g. due to an asynchronous data acquisition method such as an HTTP request) the source must still be created, even if it is empty. This can be accomplished in these cases with the follow line:

 setData(name, DataEngine::Data());

Parameters

source the name of the source that has been requested

Returns: true if a DataContainer was set up, false otherwise

Definition at line 148 of file dataengine.cpp.

◆ sources()

QStringList Plasma::DataEngine::sources ( ) const

virtual

Returns: a list of all the data sources available via this DataEngine Whether these sources are currently available (which is what the default implementation provides) or not is up to the DataEngine to decide.

Definition at line 75 of file dataengine.cpp.

◆ timerEvent()

void Plasma::DataEngine::timerEvent ( QTimerEvent * event )

overrideprotectedvirtual

Reimplemented from QObject.

Definition at line 339 of file dataengine.cpp.

◆ updateAllSources

void Plasma::DataEngine::updateAllSources ( )

protectedslot

Immediately updates all existing sources when called.

Definition at line 371 of file dataengine.cpp.

◆ updateSourceEvent()

bool Plasma::DataEngine::updateSourceEvent ( const QString & source )

protectedvirtual

Called by internal updating mechanisms to trigger the engine to refresh the data contained in a given source.

Reimplement this method when using facilities such as setPollingInterval.

See also: setPollingInterval

Parameters

source the name of the source that should be updated

Returns: true if the data was changed, or false if there was no change or if the change will occur later

Definition at line 157 of file dataengine.cpp.

The documentation for this class was generated from the following files:

QString

QMap

KDE's Doxygen guidelines are available online.

Class Picker

Quick Links

About Plasma

Plasma::DataEngine

Public Types

Signals

Public Member Functions

Protected Slots

Protected Member Functions

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ DataEngine() [1/2]

◆ DataEngine() [2/2]

Member Function Documentation

◆ addSource()

◆ connectAllSources()

◆ connectSource()

◆ containerDict()

◆ containerForSource()

◆ disconnectSource()

◆ forceImmediateUpdateOfAllVisualizations

◆ isEmpty()

◆ isValid()

◆ metadata()

◆ minimumPollingInterval()

◆ modelForSource()

◆ package()

◆ pluginInfo()

◆ removeAllData()

◆ removeAllSources()

◆ removeData()

◆ removeSource

◆ serviceForSource()

◆ setData() [1/3]

◆ setData() [2/3]

◆ setData() [3/3]

◆ setMinimumPollingInterval()

◆ setModel()

◆ setPollingInterval()

◆ setStorageEnabled()

◆ setValid()

◆ sourceAdded

◆ sourceRemoved

◆ sourceRequestEvent()

◆ sources()

◆ timerEvent()

◆ updateAllSources

◆ updateSourceEvent()