KCoreAddons - KPluginFactory Class Reference

View on LXR

#include <KPluginFactory>

Inheritance diagram for KPluginFactory:

[legend]

Classes
struct	InheritanceChecker

Signals
void	objectCreated (QObject *object)

Public Member Functions
	KPluginFactory ()

	~KPluginFactory () override

template<typename T >
T *	create (QObject *parent=nullptr, const QVariantList &args=QVariantList())

template<typename T >
T *	create (const QString &keyword, QObject *parent=nullptr, const QVariantList &args=QVariantList())

template<typename T >
T *	create (QWidget parentWidget, QObject parent, const QString &keyword=QString(), const QVariantList &args=QVariantList())

template<typename T >
T *	create (QObject *parent, const QStringList &args)

QObject *	create (QObject parent=nullptr, const char classname="QObject", const QStringList &args=QStringList())

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

bool	blockSignals (bool block)

const QObjectList &	children () const

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

void	deleteLater ()

void	destroyed (QObject *obj)

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

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

void	dumpObjectInfo ()

void	dumpObjectTree ()

QList< QByteArray >	dynamicPropertyNames () const

virtual bool	event (QEvent *e)

virtual bool	eventFilter (QObject watched, QEvent event)

T	findChild (const QString &name, QFlags< Qt::FindChildOption > options) const

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

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

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

bool	inherits (const char *className) const

void	installEventFilter (QObject *filterObj)

bool	isWidgetType () const

bool	isWindowType () const

void	killTimer (int id)

virtual const QMetaObject *	metaObject () const

void	moveToThread (QThread *targetThread)

QString	objectName () const

void	objectNameChanged (const QString &objectName)

QObject *	parent () const

QVariant	property (const char *name) const

void	removeEventFilter (QObject *obj)

void	setObjectName (const QString &name)

void	setParent (QObject *parent)

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

bool	signalsBlocked () const

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

QThread *	thread () const

Static Public Member Functions
static QVariantList	stringListToVariantList (const QStringList &list)

static QStringList	variantListToStringList (const QVariantList &list)

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 receiver, PointerToMemberFunction method, Qt::ConnectionType type)

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

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

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, PointerToMemberFunction signal, const QObject receiver, PointerToMemberFunction method)

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

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

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

Protected Types
typedef QObject (	CreateInstanceFunction) (QWidget , QObject , const QVariantList &)

Protected Member Functions
	KPluginFactory (KPluginFactoryPrivate &dd)

virtual QObject *	create (const char iface, QWidget parentWidget, QObject *parent, const QVariantList &args, const QString &keyword)

virtual QObject *	createObject (QObject parent, const char className, const QStringList &args)

virtual KParts::Part *	createPartObject (QWidget parentWidget, QObject parent, const char *classname, const QStringList &args)

template<class T >
void	registerPlugin (const QString &keyword=QString(), CreateInstanceFunction instanceFunction=InheritanceChecker< T >().createInstanceFunction(static_cast< T * >(nullptr)))

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

int	receivers (const char *signal) const

QObject *	sender () const

int	senderSignalIndex () const

virtual void	timerEvent (QTimerEvent *event)

Static Protected Member Functions
template<class impl , class ParentType >
static QObject *	createInstance (QWidget parentWidget, QObject parent, const QVariantList &args)

template<class impl >
static QObject *	createPartInstance (QWidget parentWidget, QObject parent, const QVariantList &args)

Protected Attributes
KPluginFactoryPrivate *const	d_ptr

Related Functions
(Note that these are not member functions.)
#define	K_PLUGIN_CLASS_WITH_JSON(classname, jsonFile) K_PLUGIN_FACTORY_WITH_JSON(classname ## Factory, jsonFile, registerPlugin<classname >();)

#define	K_PLUGIN_FACTORY(name, pluginRegistrations) K_PLUGIN_FACTORY_WITH_BASEFACTORY(name, KPluginFactory, pluginRegistrations)

#define	K_PLUGIN_FACTORY_DECLARATION(name) K_PLUGIN_FACTORY_DECLARATION_WITH_BASEFACTORY(name, KPluginFactory)

#define	K_PLUGIN_FACTORY_DEFINITION(name, pluginRegistrations) K_PLUGIN_FACTORY_DEFINITION_WITH_BASEFACTORY(name, KPluginFactory, pluginRegistrations)

#define	K_PLUGIN_FACTORY_WITH_JSON(name, jsonFile, pluginRegistrations) K_PLUGIN_FACTORY_WITH_BASEFACTORY_JSON(name, KPluginFactory, jsonFile, pluginRegistrations)

Additional Inherited Members
Properties inherited from QObject
	objectName

Detailed Description

KPluginFactory provides a convenient way to provide factory-style plugins.

Qt plugins provide a singleton object, but a common pattern is for plugins to generate as many objects of a particular type as the application requires. By using KPluginFactory, you can avoid implementing the factory pattern yourself.

KPluginFactory also allows plugins to provide multiple different object types, indexed by keywords.

The objects created by KPluginFactory must inherit QObject, and must have a standard constructor pattern:

if the object is a KPart::Part, it must be of the form
T(QWidget *parentWidget, QObject *parent, const QVariantList &args)
if it is a QWidget, it must be of the form
T(QWidget *parent, const QVariantList &args)
otherwise it must be of the form
T(QObject *parent, const QVariantList &args)

You should typically use either K_PLUGIN_FACTORY() or K_PLUGIN_FACTORY_WITH_JSON() in your plugin code to create the factory. The typical pattern is

#include <KPluginFactory>
#include <plugininterface.h>
class MyPlugin : public PluginInterface
{
public:
    MyPlugin(QObject *parent, const QVariantList &args)
        : PluginInterface(parent)
    {}
};
K_PLUGIN_FACTORY(MyPluginFactory,
                 registerPlugin<MyPlugin>();
                )
#include <myplugin.moc>

If you want to write a custom KPluginFactory not using the standard macro(s) you can reimplement the create(const char *iface, QWidget *parentWidget, QObject *parent, const QVariantList &args, const QString &keyword) method.

Example:

class SomeScriptLanguageFactory : public KPluginFactory
{
    Q_OBJECT
public:
    SomeScriptLanguageFactory()
    {}
protected:
    virtual QObject *create(const char *iface, QWidget *parentWidget, QObject *parent, const QVariantList &args, const QString &keyword)
    {
        const QString identifier = QLatin1String(iface) + QLatin1Char('_') + keyword;
        // load scripting language module from the information in identifier
        // and return it:
        return object;
    }
};

If you want to load a library use KPluginLoader. The application that wants to instantiate plugin classes can do the following:

KPluginFactory *factory = KPluginLoader("libraryname").factory();
if (factory) {
    PluginInterface *p1 = factory->create<PluginInterface>(parent);
    OtherInterface *p2  = factory->create<OtherInterface>(parent);
    NextInterface *p3   = factory->create<NextInterface>("keyword1", parent);
    NextInterface *p3   = factory->create<NextInterface>("keyword2", parent);
}

Author: Matthias Kretz kretz[email protected]@kde[email protected].org; Bernhard Loos nhuh.[email protected][email protected][email protected]web.d[email protected]e

Definition at line 330 of file kpluginfactory.h.

Member Typedef Documentation

typedef QObject*(* KPluginFactory::CreateInstanceFunction) (QWidget *, QObject *, const QVariantList &)

protected

Function pointer type to a function that instantiates a plugin.

Definition at line 429 of file kpluginfactory.h.

Constructor & Destructor Documentation

KPluginFactory::KPluginFactory ( )

explicit

This constructor creates a factory for a plugin.

Definition at line 32 of file kpluginfactory.cpp.

KPluginFactory::~KPluginFactory ( )

override

This destroys the PluginFactory.

Definition at line 47 of file kpluginfactory.cpp.

Member Function Documentation

template<typename T >

T * KPluginFactory::create	(	QObject *	parent = `nullptr`,
		const QVariantList &	args = `QVariantList()`
	)

inline

Use this method to create an object.

It will try to create an object which inherits T. If it has multiple choices it's not defined which object will be returned, so be careful to request a unique interface or use keywords.

Template Parameters

T	The interface for which an object should be created. The object will inherit `T`.

Parameters

parent	The parent of the object. If `parent` is a widget type, it will also passed to the parentWidget argument of the CreateInstanceFunction for the object.
args	Additional arguments which will be passed to the object.

Returns: A pointer to the created object is returned, or nullptr if an error occurred.

Definition at line 548 of file kpluginfactory.h.

template<typename T >

T * KPluginFactory::create	(	const QString &	keyword,
		QObject *	parent = `nullptr`,
		const QVariantList &	args = `QVariantList()`
	)

inline

Use this method to create an object.

It will try to create an object which inherits T and was registered with keyword.

Template Parameters

T	The interface for which an object should be created. The object will inherit `T`.

Parameters

keyword	The keyword of the object.
parent	The parent of the object. If `parent` is a widget type, it will also passed to the parentWidget argument of the CreateInstanceFunction for the object.
args	Additional arguments which will be passed to the object.

Returns: A pointer to the created object is returned, or nullptr if an error occurred.

Definition at line 560 of file kpluginfactory.h.

template<typename T >

T * KPluginFactory::create	(	QWidget *	parentWidget,
		QObject *	parent,
		const QString &	keyword = `QString()`,
		const QVariantList &	args = `QVariantList()`
	)

inline

Use this method to create an object.

It will try to create an object which inherits T and was registered with keyword. This overload has an additional parentWidget argument, which is used by some plugins (e.g. Parts).

Template Parameters

T	The interface for which an object should be created. The object will inherit `T`.

Parameters

parentWidget	An additional parent widget.
parent	The parent of the object. If `parent` is a widget type, it will also passed to the parentWidget argument of the CreateInstanceFunction for the object.
keyword	The keyword of the object.
args	Additional arguments which will be passed to the object.

Returns: A pointer to the created object is returned, or nullptr if an error occurred.

Definition at line 572 of file kpluginfactory.h.

template<typename T >

T* KPluginFactory::create	(	QObject *	parent,
		const QStringList &	args
	)

inline

Deprecated:: since 4.0 use create<T>(QObject *parent, const QVariantList &args)

Definition at line 395 of file kpluginfactory.h.

QObject* KPluginFactory::create	(	QObject *	parent = `nullptr`,
		const char *	classname = `"QObject"`,
		const QStringList &	args = `QStringList()`
	)

inline

Deprecated:: since 4.0 use create<T>(QObject *parent, const QVariantList &args)

Definition at line 404 of file kpluginfactory.h.

QObject * KPluginFactory::create	(	const char *	iface,
		QWidget *	parentWidget,
		QObject *	parent,
		const QVariantList &	args,
		const QString &	keyword
	)

protectedvirtual

This function is called when the factory asked to create an Object.

You may reimplement it to provide a very flexible factory. This is especially useful to provide generic factories for plugins implemented using a scripting language.

Parameters

iface	The staticMetaObject::className() string identifying the plugin interface that was requested. E.g. for KCModule plugins this string will be "KCModule".
parentWidget	Only used if the requested plugin is a KPart.
parent	The parent object for the plugin object.
args	A plugin specific list of arbitrary arguments.
keyword	A string that uniquely identifies the plugin. If a KService is used this keyword is read from the X-KDE-PluginKeyword entry in the .desktop file.

Definition at line 113 of file kpluginfactory.cpp.

QObject * KPluginFactory::createObject	(	QObject *	parent,
		const char *	className,
		const QStringList &	args
	)

protectedvirtual

Deprecated:: since 4.0 use create<T>(QObject *parent, const QVariantList &args)

Reimplemented in KParts::Factory.

Definition at line 93 of file kpluginfactory.cpp.

KParts::Part * KPluginFactory::createPartObject	(	QWidget *	parentWidget,
		QObject *	parent,
		const char *	classname,
		const QStringList &	args
	)

protectedvirtual

Deprecated:: since 4.0 use create<T>(QWidget *parentWidget, QObject *parent, const QString &keyword, const QVariantList &args)

Reimplemented in KParts::Factory, and KParts::GenericFactory< class >.

Definition at line 103 of file kpluginfactory.cpp.

template<class T >

void KPluginFactory::registerPlugin	(	const QString &	keyword = `QString()`,
		CreateInstanceFunction	instanceFunction = `InheritanceChecker<T>().createInstanceFunction(static_cast<T *>(nullptr))`
	)

inlineprotected

Registers a plugin with the factory.

Call this function from the constructor of the KPluginFactory subclass to make the create function able to instantiate the plugin when asked for an interface the plugin implements.

You can register as many plugin classes as you want as long as either the plugin interface or the keyword makes it unique. E.g. it is possible to register a KCModule and a KParts::Part without having to specify keywords since their interfaces differ.

Template Parameters

T	the name of the plugin class

Parameters

keyword An optional keyword as unique identifier for the plugin. This allows you to put more than one plugin with the same interface into the same library using the same factory. X-KDE-PluginKeyword is a convenient way to specify the keyword in a desktop file.

instanceFunction

A function pointer to a function that creates an instance of the plugin. The default function that will be used depends on the type of interface. If the interface inherits from

KParts::Part the function will call
new T(QWidget *parentWidget, QObject *parent, const QVariantList &args)
QWidget the function will call
new T(QWidget *parent, const QVariantList &args)
else the function will call
new T(QObject *parent, const QVariantList &args)

Definition at line 485 of file kpluginfactory.h.

QVariantList KPluginFactory::stringListToVariantList ( const QStringList & list )

static

Converts a QStringList to a QVariantList

Definition at line 166 of file kpluginfactory.cpp.

QStringList KPluginFactory::variantListToStringList ( const QVariantList & list )

static

Converts a QVariantList of strings to a QStringList

Definition at line 157 of file kpluginfactory.cpp.

Friends And Related Function Documentation

#define K_PLUGIN_CLASS_WITH_JSON	(	classname,
		jsonFile
	)	K_PLUGIN_FACTORY_WITH_JSON(classname ## Factory, jsonFile, registerPlugin<classname >();)

Create a KPluginFactory subclass and export it as the root plugin object with JSON metadata.

This macro does the same as K_PLUGIN_FACTORY_WITH_JSON, but you only have to pass the class name and the json file. The factory name and registerPlugin call are deduced from the class name.

#include <myplugin.moc>

in the same source file when that one has the name "myplugin.cpp".

Example:

#include <KPluginFactory>
#include <plugininterface.h>
class MyPlugin : public PluginInterface
{
public:
    MyPlugin(QObject *parent, const QVariantList &args)
        : PluginInterface(parent)
    {}
};
K_PLUGIN_CLASS_WITH_JSON(MyPlugin, "metadata.json")
#include <myplugin.moc>

See also: K_PLUGIN_FACTORY_WITH_JSON

Since: 5.44

Definition at line 211 of file kpluginfactory.h.

#define K_PLUGIN_FACTORY	(	name,
		pluginRegistrations
	)	K_PLUGIN_FACTORY_WITH_BASEFACTORY(name, KPluginFactory, pluginRegistrations)

Create a KPluginFactory subclass and export it as the root plugin object.

Parameters

name	The name of the KPluginFactory derived class.
pluginRegistrations	Code to be inserted into the constructor of the class. Usually a series of registerPlugin() calls.

Note: K_PLUGIN_FACTORY declares the subclass including a Q_OBJECT macro. So you need to make sure to have Qt's moc run also for the source file where you use the macro. E.g. in projects using CMake and it's automoc feature, as usual you need to have a line
#include <myplugin.moc>
in the same source file when that one has the name "myplugin.cpp".

Example:

#include <KPluginFactory>
#include <plugininterface.h>
class MyPlugin : public PluginInterface
{
public:
    MyPlugin(QObject *parent, const QVariantList &args)
        : PluginInterface(parent)
    {}
};
K_PLUGIN_FACTORY(MyPluginFactory,
                 registerPlugin<MyPlugin>();
                )
#include <myplugin.moc>

If you want to compile a .json file into the plugin, use K_PLUGIN_FACTORY_WITH_JSON.

See also: K_PLUGIN_FACTORY_WITH_JSON; K_PLUGIN_FACTORY_DECLARATION; K_PLUGIN_FACTORY_DEFINITION

Definition at line 119 of file kpluginfactory.h.

#define K_PLUGIN_FACTORY_DECLARATION ( name ) K_PLUGIN_FACTORY_DECLARATION_WITH_BASEFACTORY(name, KPluginFactory)

K_PLUGIN_FACTORY_DECLARATION declares the KPluginFactory subclass. This macro can be used in a header file.

Parameters

name	The name of the KPluginFactory derived class.

See also: K_PLUGIN_FACTORY; K_PLUGIN_FACTORY_DEFINITION

Definition at line 224 of file kpluginfactory.h.

#define K_PLUGIN_FACTORY_DEFINITION	(	name,
		pluginRegistrations
	)	K_PLUGIN_FACTORY_DEFINITION_WITH_BASEFACTORY(name, KPluginFactory, pluginRegistrations)

K_PLUGIN_FACTORY_DEFINITION defines the KPluginFactory subclass. This macro can not be used in a header file.

Parameters

name	The name of the KPluginFactory derived class.
pluginRegistrations	Code to be inserted into the constructor of the class. Usually a series of registerPlugin() calls.

See also: K_PLUGIN_FACTORY; K_PLUGIN_FACTORY_DECLARATION

Definition at line 239 of file kpluginfactory.h.

#define K_PLUGIN_FACTORY_WITH_JSON	(	name,
		jsonFile,
		pluginRegistrations
	)	K_PLUGIN_FACTORY_WITH_BASEFACTORY_JSON(name, KPluginFactory, jsonFile, pluginRegistrations)

Create a KPluginFactory subclass and export it as the root plugin object with JSON metadata.

This macro does the same as K_PLUGIN_FACTORY, but adds a JSON file as plugin metadata. See Q_PLUGIN_METADATA() for more information.

Parameters

name	The name of the KPluginFactory derived class.
pluginRegistrations	Code to be inserted into the constructor of the class. Usually a series of registerPlugin() calls.
jsonFile	Name of the json file to be compiled into the plugin as metadata

Note: K_PLUGIN_FACTORY_WITH_JSON declares the subclass including a Q_OBJECT macro. So you need to make sure to have Qt's moc run also for the source file where you use the macro. E.g. in projects using CMake and it's automoc feature, as usual you need to have a line
#include <myplugin.moc>
in the same source file when that one has the name "myplugin.cpp".

Example:

#include <KPluginFactory>
#include <plugininterface.h>
class MyPlugin : public PluginInterface
{
public:
    MyPlugin(QObject *parent, const QVariantList &args)
        : PluginInterface(parent)
    {}
};
K_PLUGIN_FACTORY_WITH_JSON(MyPluginFactory,
                 "metadata.json",
                 registerPlugin<MyPlugin>();
                )
#include <myplugin.moc>

See also: K_PLUGIN_FACTORY; K_PLUGIN_FACTORY_DECLARATION; K_PLUGIN_FACTORY_DEFINITION

Since: 5.0

Definition at line 173 of file kpluginfactory.h.

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

KDE's Doxygen guidelines are available online.

Quick Links

Class Picker

About

KPluginFactory

Classes

Signals

Public Member Functions

Static Public Member Functions

Protected Types

Protected Member Functions

Static Protected Member Functions

Protected Attributes

Related Functions

Additional Inherited Members

Detailed Description

Member Typedef Documentation

Constructor & Destructor Documentation

Member Function Documentation

Friends And Related Function Documentation