Plasma/libplasma2/API Review/DataEngine

API

Status	Action	Method
DONE	Remove	explicit DataEngine(QObject *parent , KService::Ptr service);
DONE	Add	explicit DataEngine(QObject *parent, const KPluginInfo &info);
DONE	Remove	DataEngine(QObject *parent, const QVariantList &args);
DONE	Keep	~DataEngine();
DONE	Remove?	virtual void init(); can be removed is there will be only one constructor
DONE	Keep	virtual QStringList sources() const;
DONE	Keep	virtual Service *serviceForSource(const QString &source);
DONE	Add	KPluginInfo pluginInfo() const;
DONE	Remove	QString name() const;
DONE	Remove	QString icon() const;
DONE	Remove	QString pluginName() const;
DONE	Keep	void connectSource(const QString &source, QObject *visualization, uint pollingInterval, Plasma::IntervalAlignment intervalAlignment ) const;
DONE	Keep	void connectAllSources(QObject *visualization, uint pollingInterval, Plasma::IntervalAlignment intervalAlignment) const;
DONE	Keep	void disconnectSource(const QString &source, QObject *visualization) const;
DONE	Keep	DataContainer *containerForSource(const QString &source);
DONE	Remove	DataEngine::Data query(const QString &source) const;
DONE	Keep	bool isValid() const;
DONE	Keep	bool isEmpty() const;
DONE	Keep	Package package() const;
DONE	Remove	Service* createDefaultService(QObject *parent );
DONE	Move	static QStringList listAllEngines(const QString &parentApp); -> in PluginLoader
DONE	Move	static KPluginInfo::List listEngineInfo(const QString &parentApp); -> in PluginLoader
DONE	Move	static KPluginInfo::List listEngineInfoByCategory(const QString &category, const QString &parentApp);
DONE	Keep	void sourceAdded(const QString &source);
DONE	Keep	void sourceRemoved(const QString &source);
DONE	Keep	virtual bool sourceRequestEvent(const QString &source);
DONE	Keep	virtual bool updateSourceEvent(const QString &source);
DONE	Keep	void setData(const QString &source, const QVariant &value);
DONE	Keep	void setData(const QString &source, const QString &key, const QVariant &value);
DONE	Signature	void setData(const QString &source, const Data ->QHash<QString, QVariant> &data); -> Data becomes QHash<QString, QVariant>
DONE	Keep	void removeAllData(const QString &source);
DONE	Keep	void removeData(const QString &source, const QString &key);
DONE	Keep	void addSource(DataContainer *source);
DONE	Keep	void setMinimumPollingInterval(int minimumMs);
DONE	Keep	int minimumPollingInterval() const;
DONE	Keep	void setPollingInterval(uint frequency);
DONE	Keep	void removeAllSources();
DONE	Keep	void setValid(bool valid);
DONE	Signature	SourceDict -> QHash<QString, DataContainer*> containerDict() const;
DONE	Keep	void timerEvent(QTimerEvent *event);
DONE	Remove	void setName(const QString &name);
DONE	Remove	void setIcon(const QString &icon);
DONE	Remove	void setDefaultService(const QString &serviceName);
DONE	Keep	void setStorageEnabled(const QString &source, bool store);
DONE	Move	slot void scheduleSourcesUpdated(); -> to private class
DONE	Keep	slot void removeSource(const QString &source);
DONE	Keep	slot void updateAllSources();
DONE	Keep	slot void forceImmediateUpdateOfAllVisualizations();

DataEngine functionality currently:

   * Timed updates
   * Ease of item creation and update
   * Item destruction when not used
   * Service integration

DataEngine functionality missing:

   * Introspection / self-documenting structures
   * Ability to represent as model internally

Open Questions

These questions have come up during review-review, and should be clarified to users of our API:

   * When to write a DataEngine, when to use an import? (In a world, where we have import security)
   * Add possibility to expose QObject*s in the API, much like QAIM*s
   * Why have QVariant(Map,Hash) *and* models, why not deprecate one?
   * Should we deprecate the QVariant*, now we have models?

QML Access

   * Can haz a model?

DataEngine {
public:
	QAbstractItemModel *model() const;
}

DataSource {
	engine: “keystate”
	sources: “*Button”
	fields: {“Pressed”}
}

Example of source types of twitter engine

Twitter			tweets		posting
identi.ca 1		dents		posting
identi.ca 2 		dents		posting
avatars		model { name : picture }

TwitterModel *model = new TwitterModel(“twitter account foo”); setData(“twitter account foo”, model);

bool pressedState = false; setData(“key”, “pressed”, pressedState);

DataContainer -> model, or contains a model …

What do we want?

• lifecycle management
• ondemand creation
• keep existing API (setData, service-related stuff)
• make it easy to use “3rd party models” (e.g. some akonadi model)

Current dataengines

• akonadi - Akonadi PIM data engine
• applicationjobs - Application job updates (via kuiserver)
• apps - Information and launching of all applications in * the app menu.
• calendar - Calendar data engine
• comic - Online comic strips
• devicenotifications - Passive device notifications for the user.
• dict - Look up word meanings
• executable - Run Executable Data Engine
• favicons - Data Engine for getting favicons of web sites
• filebrowser - Information about files and directories.
• geolocation - Geolocation Data Engine
• hotplug - Tracks hot-pluggable devices as they appear and disappear.
• kdeobservatory - A Data Engine for acquiring consolidated data about KDE projects
• keystate - Keyboard modifier and mouse buttons states
• kget - No description available
• kimpanel - DataEngine for Kimpanel
• kremotecontrol - Data engine for kremotecontrol
• ktorrent - KTorrent data engine, for getting information from KTorrent
• metadata - No description available
• microblog - identi.ca and twitter micro-blogging services
• mixer - No description available
• mouse - Mouse position and cursor
• mpris2 - Provides information from and control over media players via MPRIS2
• network - Network interface information
• networkmanagement - Network Manager data engine
• notifications - Passive visual notifications for the user.
• nowplaying - Lists currently playing music
• obsdataengine - DataEngine to make API Calls to the Open Build Service
• ocs - No description available
• openstreetmap - The OpenStreetMap data engine can be used to query things near the user.
• org.kde.active.apps - Information and launching of all applications in the app menu.
• org.kde.active.bookmarks - Bookmarks from Nepomuk
• org.kde.active.capabilities - Provides information and services for device-specific aspects
• org.kde.active.customsearch - Provides metadata for custom searches in semantic resources
• org.kde.active.metadata - Provides metadata for semantic resources
• org.kde.active.persons - Provides metadata for custom searches in semantic resources
• org.kde.activities - Information on Plasma Activities
• org.kde.alarms - List and set Akonadi Alarms
• org.kde.devicecapabilities - Provides information and services for device-specific aspects
• org.kde.examples.customDataContainers - A demonstration of how to subclass DataContainer
• org.kde.examples.simpleEngine - A very basic DataEngine implementation
• org.kde.examples.sourcesOnRequest - A DataEngine example showing how to respond to requests for source creation and updates
• org.kde.konqprofiles - List and launch Konqueror profiles
• org.kde.konsoleprofiles - List and launch Konsole profiles
• org.kde.mobilenetworkengine - Mobile network engine
• org.kde.mobileprofileengine - No description available
• org.kde.plasma.dataengine.share - Engine to share content using different services
• org.kde.preview - Shows previews for webpages
• org.kde.printers - No description available
• org.kde.printjobs - No description available
• org.kde.runner - Query KRunner and execute the results
• org.kde.sharelikeconnect - Provider of actions for sharing resources
• parley - Vocabulary data for Plasmoids
• places - Places, as seen in the file manager and in file dialogs.
• potd - Data Engine for getting various online Pictures of The Day.
• powermanagement - Battery, AC, sleep and PowerDevil information.
• publictransport - Plasma data engine for public transport
• rss - RSS News Data Engine
• rtm - An engine to work with Remember the Milk.
• searchlaunch - Engine to handle queries to SAL containment
• soliddevice - Device data via Solid
• statusnotifieritem - Engine for applications' status information, based on the Status Notifier protocol.
• systemmonitor - System status information
• tasks - Information and management services for all available windows.
• time - Date and time by timezone
• weather - Weather data from multiple online sources
• workareas - Workareas Data Engine, as described in the WorkFlow Project