#include <Plasma/DataContainer>

Inheritance diagram for Plasma::DataContainer:

Public Slots
void	disconnectVisualization (QObject *visualization)

void	forceImmediateUpdate ()

Signals
void	becameUnused (const QString &source)

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

void	updateRequested (DataContainer *source)

Public Member Functions
	DataContainer (QObject *parent=0)

virtual	~DataContainer ()

void	connectVisualization (QObject *visualization, uint pollingInterval, Plasma::IntervalAlignment alignment)

const DataEngine::Data	data () const

DataEngine *	getDataEngine ()

bool	isStorageEnabled () const

bool	needsToBeStored () const

void	removeAllData ()

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

void	setNeedsToBeStored (bool store)

void	setStorageEnabled (bool store)

bool	visualizationIsConnected (QObject *visualization) const

Protected Slots
void	checkUsage ()

void	timerEvent (QTimerEvent *event)

Protected Member Functions
void	checkForUpdate ()

void	setNeedsUpdate (bool update=true)

uint	timeSinceLastUpdate () const

Detailed Description

A set of data exported via a DataEngine.

Plasma::DataContainer wraps the data exported by a DataEngine implementation, providing a generic wrapper for the data.

A DataContainer may have zero or more associated pieces of data which are keyed by strings. The data itself is stored as QVariants. This allows easy and flexible retrieval of the information associated with this object without writing DataContainer or DataEngine specific code in visualizations.

If you are creating your own DataContainer objects (and are passing them to DataEngine::addSource()), you normally just need to listen to the updateRequested() signal (as well as any other methods you might have of being notified of new data) and call setData() to actually update the data. Then you need to either trigger the scheduleSourcesUpdated signal of the parent DataEngine or call checkForUpdate() on the DataContainer.

You also need to set a suitable name for the source with setObjectName(). See DataEngine::addSource() for more information.

Note that there is normally no need to subclass DataContainer, except as a way of encapsulating the data retrieval for a source, since all notifications are done via signals rather than virtual methods.

Definition at line 63 of file datacontainer.h.

Constructor & Destructor Documentation

Plasma::DataContainer::DataContainer ( QObject * parent = 0 )

explicit

Constructs a default DataContainer that has no name or data associated with it.

Definition at line 30 of file datacontainer.cpp.

Plasma::DataContainer::~DataContainer ( )

virtual

Definition at line 36 of file datacontainer.cpp.

Member Function Documentation

void Plasma::DataContainer::becameUnused ( const QString & source )

signal

Emitted when the last visualization is disconnected.

Note that if this source was created by DataEngine::sourceRequestEvent(), it will be deleted by DataEngine once control returns to the event loop after this signal is emitted.

Parameters

source the name of the source that became unused

void Plasma::DataContainer::checkForUpdate ( )

protected

Checks whether any data has changed and, if so, emits dataUpdated().

Definition at line 290 of file datacontainer.cpp.

void Plasma::DataContainer::checkUsage ( )

protectedslot

Check if the DataContainer is still in use.

If not the signal "becameUnused" will be emitted.

Warning: The DataContainer may be invalid after calling this function, because a listener to becameUnused() may have deleted it.

Definition at line 328 of file datacontainer.cpp.

void Plasma::DataContainer::connectVisualization	(	QObject *	visualization,
		uint	pollingInterval,
		Plasma::IntervalAlignment	alignment
	)

Connects an object to this DataContainer.

May be called repeatedly for the same visualization without side effects

Parameters

visualization	the object to connect to this DataContainer
pollingInterval	the time in milliseconds between updates
alignment	the clock position to align updates to

Definition at line 85 of file datacontainer.cpp.

const DataEngine::Data Plasma::DataContainer::data ( ) const

Returns the data for this DataContainer.

Definition at line 41 of file datacontainer.cpp.

void Plasma::DataContainer::dataUpdated	(	const QString &	source,
		const Plasma::DataEngine::Data &	data
	)

signal

Emitted when the data has been updated, allowing visualizations to reflect the new data.

Note that you should not normally emit this directly. Instead, use checkForUpdate() or the DataEngine::scheduleSourcesUpdated() slot.

Parameters

source	the objectName() of the DataContainer (and hence the name of the source) that updated its data
data	the updated data

void Plasma::DataContainer::disconnectVisualization ( QObject * visualization )

slot

Disconnects an object from this DataContainer.

Note that if this source was created by DataEngine::sourceRequestEvent(), it will be deleted by DataEngine once control returns to the event loop.

Definition at line 264 of file datacontainer.cpp.

void Plasma::DataContainer::forceImmediateUpdate ( )

slot

Forces immediate update signals to all visualizations.

Since: 4.4

Definition at line 304 of file datacontainer.cpp.

DataEngine * Plasma::DataContainer::getDataEngine ( )

Returns: the DataEngine that the DataContainer is a child of.

Definition at line 172 of file datacontainer.cpp.

bool Plasma::DataContainer::isStorageEnabled ( ) const

Returns: true if the data container has been marked for storage

Since: 4.6

Definition at line 157 of file datacontainer.cpp.

bool Plasma::DataContainer::needsToBeStored ( ) const

Returns: true if the data container has been updated, but not stored

Definition at line 162 of file datacontainer.cpp.

void Plasma::DataContainer::removeAllData ( )

Removes all data currently associated with this source.

If you call removeAllData() on a DataContainer, you need to either trigger the scheduleSourcesUpdated() slot for the data engine it belongs to or call checkForUpdate() on the DataContainer.

Definition at line 68 of file datacontainer.cpp.

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

Set a value for a key.

This also marks this source as needing to signal an update.

If you call setData() directly on a DataContainer, you need to either trigger the scheduleSourcesUpdated() slot for the data engine it belongs to or call checkForUpdate() on the DataContainer.

Parameters

key	a string used as the key for the data
value	a QVariant holding the actual data. If a invalid QVariant is passed in and the key currently exists in the data, then the data entry is removed

Definition at line 46 of file datacontainer.cpp.

void Plasma::DataContainer::setNeedsToBeStored ( bool store )

sets that the data container needs to be stored or not.

Parameters

whether the data container needs to be stored

Definition at line 167 of file datacontainer.cpp.

void Plasma::DataContainer::setNeedsUpdate ( bool update = true )

protected

Indicates that the data should be treated as dirty the next time hasUpdates() is called.

This is needed for the case where updateRequested() is triggered but we don't want to update the data immediately because it has just been updated. The second request won't be fulfilled in this case, because we never updated the data and so never called checkForUpdate(). So we claim it needs an update anyway.

Definition at line 323 of file datacontainer.cpp.

void Plasma::DataContainer::setStorageEnabled ( bool store )

sets this data container to be automatically stored.

Parameters

whether this data container should be stored

Since: 4.6

Definition at line 147 of file datacontainer.cpp.

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

protectedslot

Reimplemented from superclass. from QObject

Definition at line 335 of file datacontainer.cpp.

uint Plasma::DataContainer::timeSinceLastUpdate ( ) const

protected

Returns how long ago, in msecs, that the data in this container was last updated.

This is used by DataEngine to compress updates that happen more quickly than the minimum polling interval by calling setNeedsUpdate() instead of calling updateSourceEvent() immediately.

Definition at line 316 of file datacontainer.cpp.

void Plasma::DataContainer::updateRequested ( DataContainer * source )

signal

Emitted when an update is requested.

If a polling interval was passed connectVisualization(), this signal will be emitted every time the interval expires.

Note that if you create your own DataContainer (and pass it to DataEngine::addSource()), you will need to listen to this signal and refresh the data when it is triggered.

Parameters

source the datacontainer the update was requested for. Useful for classes that update the data for several containers.

bool Plasma::DataContainer::visualizationIsConnected ( QObject * visualization ) const

Returns: true if the visualization is currently connected

Definition at line 80 of file datacontainer.cpp.

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

Plasma

Public Slots

Signals

Public Member Functions

Protected Slots

Protected Member Functions

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation

Plasma

kdelibs API Reference

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