QScxmlStateMachine Class

The QScxmlStateMachine class provides an interface to the state machines created from SCXML files. More...

Header:	#include <QScxmlStateMachine>
qmake:	QT += scxml
Since:	Qt 5.7
Instantiated By:	ScxmlStateMachine
Inherits:	QObject

This class was introduced in Qt 5.7.

• List of all members, including inherited members

Properties

dataModel : QScxmlDataModel* initialValues : QVariantMap initialized : const bool invoked : const bool invokedServices : QVector<QScxmlInvokableService*> const loader : QScxmlCompiler::Loader*

name : const QString parseErrors : const QVector<QScxmlError> running : bool sessionId : const QString tableData : QScxmlTableData*

Public Functions

QStringList	activeStateNames(bool compress = true) const
void	cancelDelayedEvent(const QString &sendId)
QMetaObject::Connection	connectToEvent(const QString &scxmlEventSpec, const QObject *receiver, const char *method, Qt::ConnectionType type = Qt::AutoConnection)
QMetaObject::Connection	connectToEvent(const QString &scxmlEventSpec, const typename QtPrivate::FunctionPointer<PointerToMemberFunction>::Object *receiver, PointerToMemberFunction method, Qt::ConnectionType type = Qt::AutoConnection)
typename QtPrivate::QEnableIf<!QtPrivate::FunctionPointer<Functor>::IsPointerToMemberFunction && !std::is_same<const char *, Functor>::value, QMetaObject::Connection>::Type	connectToEvent(const QString &scxmlEventSpec, Functor functor, Qt::ConnectionType type = Qt::AutoConnection)
typename QtPrivate::QEnableIf<!QtPrivate::FunctionPointer<Functor>::IsPointerToMemberFunction && !std::is_same<const char *, Functor>::value, QMetaObject::Connection>::Type	connectToEvent(const QString &scxmlEventSpec, const QObject *context, Functor functor, Qt::ConnectionType type = Qt::AutoConnection)
QMetaObject::Connection	connectToState(const QString &scxmlStateName, const QObject *receiver, const char *method, Qt::ConnectionType type = Qt::AutoConnection)
QMetaObject::Connection	connectToState(const QString &scxmlStateName, const typename QtPrivate::FunctionPointer<PointerToMemberFunction>::Object *receiver, PointerToMemberFunction method, Qt::ConnectionType type = Qt::AutoConnection)
typename QtPrivate::QEnableIf<!QtPrivate::FunctionPointer<Functor>::IsPointerToMemberFunction && !std::is_same<const char *, Functor>::value, QMetaObject::Connection>::Type	connectToState(const QString &scxmlStateName, Functor functor, Qt::ConnectionType type = Qt::AutoConnection)
typename QtPrivate::QEnableIf<!QtPrivate::FunctionPointer<Functor>::IsPointerToMemberFunction && !std::is_same<const char *, Functor>::value, QMetaObject::Connection>::Type	connectToState(const QString &scxmlStateName, const QObject *context, Functor functor, Qt::ConnectionType type = Qt::AutoConnection)
QScxmlDataModel *	dataModel() const
QVariantMap	initialValues()
QVector<QScxmlInvokableService *>	invokedServices() const
bool	isActive(const QString &scxmlStateName) const
bool	isDispatchableTarget(const QString &target) const
bool	isInitialized() const
bool	isInvoked() const
bool	isRunning() const
QScxmlCompiler::Loader *	loader() const
QString	name() const
QVector<QScxmlError>	parseErrors() const
QString	sessionId() const
void	setDataModel(QScxmlDataModel *model)
void	setInitialValues(const QVariantMap &initialValues)
void	setLoader(QScxmlCompiler::Loader *loader)
void	setRunning(bool running)
void	setTableData(QScxmlTableData *tableData)
QStringList	stateNames(bool compress = true) const
void	submitEvent(QScxmlEvent *event)
void	submitEvent(const QString &eventName)
void	submitEvent(const QString &eventName, const QVariant &data)
QScxmlTableData *	tableData() const

Public Slots

bool	init()
void	start()
void	stop()

Signals

void	dataModelChanged(QScxmlDataModel *model)
void	finished()
void	initialValuesChanged(const QVariantMap &initialValues)
void	initializedChanged(bool initialized)
void	invokedServicesChanged(const QVector<QScxmlInvokableService *> &invokedServices)
void	loaderChanged(QScxmlCompiler::Loader *loader)
void	log(const QString &label, const QString &msg)
void	reachedStableState()
void	runningChanged(bool running)
void	tableDataChanged(QScxmlTableData *tableData)

Static Public Members

QScxmlStateMachine *	fromData(QIODevice *data, const QString &fileName = QString())
QScxmlStateMachine *	fromFile(const QString &fileName)
std::function<void (bool)>	onEntry(const QObject *, const char *receiver)
std::function<void (bool)>	onEntry(Functor)
std::function<void (bool)>	onEntry(const typename QtPrivate::FunctionPointer<PointerToMemberFunction>::Object *, PointerToMemberFunction receiver)
std::function<void (bool)>	onExit(const QObject *, const char *receiver)
std::function<void (bool)>	onExit(Functor)
std::function<void (bool)>	onExit(const typename QtPrivate::FunctionPointer<PointerToMemberFunction>::Object *, PointerToMemberFunction receiver)

Protected Functions

bool	isActive(int stateIndex) const

Detailed Description

QScxmlStateMachine is an implementation of the State Chart XML (SCXML).

All states that are defined in the SCXML file are accessible as properties of QScxmlStateMachine. These properties are boolean values and indicate whether the state is active or inactive.

Note: The QScxmlStateMachine needs a QEventLoop to work correctly. The event loop is used to implement the delay attribute for events and to schedule the processing of a state machine when events are received from nested (or parent) state machines.

Member Function Documentation

[signal] void QScxmlStateMachine::finished()

This signal is emitted when the state machine reaches a top-level final state.

See also running.

[slot] bool QScxmlStateMachine::init()

Initializes the state machine.

State machine initialization consists of calling QScxmlDataModel::setup(), setting the initial values for <data> elements, and executing any <script> tags of the <scxml> tag. The initial data values are taken from the initialValues property.

Returns false if parse errors occur or if any of the initialization steps fail. Returns true otherwise.

[signal] void QScxmlStateMachine::log(const QString &label, const QString &msg)

This signal is emitted if a <log> tag is used in the SCXML. label is the value of the label attribute of the <log> tag. msg is the value of the evaluated expr attribute of the <log> tag. If there is no expr attribute, a null string will be returned.

[signal] void QScxmlStateMachine::reachedStableState()

This signal is emitted when the event queue is empty at the end of a macro step or when a final state is reached.

[signal] void QScxmlStateMachine::runningChanged(bool running)

This signal is emitted when the running property is changed with running as argument.

Note: Notifier signal for property running.

[slot] void QScxmlStateMachine::start()

Starts this state machine. The machine will reset its configuration and transition to the initial state. When a final top-level state is entered, the machine will emit the finished() signal.

Note: A state machine will not run without a running event loop, such as the main application event loop started with QCoreApplication::exec() or QApplication::exec().

See also runningChanged(), setRunning(), stop(), and finished().

[slot] void QScxmlStateMachine::stop()

Stops this state machine. The machine will not execute any further state transitions. Its running property is set to false.

See also runningChanged(), start(), and setRunning().

QStringList QScxmlStateMachine::activeStateNames(bool compress = true) const

Retrieves a list of state names of all active states.

When a state is active, all its parent states are active by definition. When compress is true (the default), the parent states will be filtered out and only the leaf states will be returned. When it is false, the full list of active states will be returned.

Note: This function can be invoked via the meta-object system and from QML. See Q_INVOKABLE.

void QScxmlStateMachine::cancelDelayedEvent(const QString &sendId)

Cancels a delayed event with the specified sendId.

Note: This function can be invoked via the meta-object system and from QML. See Q_INVOKABLE.

QMetaObject::Connection QScxmlStateMachine::connectToEvent(const QString &scxmlEventSpec, const QObject *receiver, const char *method, Qt::ConnectionType type = Qt::AutoConnection)

Creates a connection of the specified type from the event specified by scxmlEventSpec to the method in the receiver object. The receiver's method may take a QScxmlEvent as a parameter. For example:

void mySlot(const QScxmlEvent &event);

In contrast to event specifications in SCXML documents, spaces are not allowed in the scxmlEventSpec here. In order to connect to multiple events with different prefixes, connectToEvent() has to be called multiple times.

Returns a handle to the connection, which can be used later to disconnect.

QMetaObject::Connection QScxmlStateMachine::connectToEvent(const QString &scxmlEventSpec, const typename QtPrivate::FunctionPointer<PointerToMemberFunction>::Object *receiver, PointerToMemberFunction method, Qt::ConnectionType type = Qt::AutoConnection)

Creates a connection of the given type from the event specified by scxmlEventSpec to method in the receiver object.

The receiver's method must take a QScxmlEvent as a parameter.

In contrast to event specifications in SCXML documents, spaces are not allowed in the scxmlEventSpec here. In order to connect to multiple events with different prefixes, connectToEvent() has to be called multiple times.

Returns a handle to the connection, which can be used later to disconnect.

typename QtPrivate::QEnableIf<!QtPrivate::FunctionPointer<Functor>::IsPointerToMemberFunction && !std::is_same<const char *, Functor>::value, QMetaObject::Connection>::Type QScxmlStateMachine::connectToEvent(const QString &scxmlEventSpec, Functor functor, Qt::ConnectionType type = Qt::AutoConnection)

Creates a connection of the given type from the event specified by scxmlEventSpec to functor.

The functor must take a QScxmlEvent as a parameter.

In contrast to event specifications in SCXML documents, spaces are not allowed in the scxmlEventSpec here. In order to connect to multiple events with different prefixes, connectToEvent() has to be called multiple times.

Returns a handle to the connection, which can be used later to disconnect.

typename QtPrivate::QEnableIf<!QtPrivate::FunctionPointer<Functor>::IsPointerToMemberFunction && !std::is_same<const char *, Functor>::value, QMetaObject::Connection>::Type QScxmlStateMachine::connectToEvent(const QString &scxmlEventSpec, const QObject *context, Functor functor, Qt::ConnectionType type = Qt::AutoConnection)

Creates a connection of the given type from the event specified by scxmlEventSpec to functor using context as context.

The functor must take a QScxmlEvent as a parameter.

In contrast to event specifications in SCXML documents, spaces are not allowed in the scxmlEventSpec here. In order to connect to multiple events with different prefixes, connectToEvent() has to be called multiple times.

Returns a handle to the connection, which can be used later to disconnect.

QMetaObject::Connection QScxmlStateMachine::connectToState(const QString &scxmlStateName, const QObject *receiver, const char *method, Qt::ConnectionType type = Qt::AutoConnection)

Creates a connection of the given type from the state identified by scxmlStateName to the method in the receiver object. The receiver's method may take a boolean argument that indicates whether the state connected became active or inactive. For example:

void mySlot(bool active);

Returns a handle to the connection, which can be used later to disconnect.

QMetaObject::Connection QScxmlStateMachine::connectToState(const QString &scxmlStateName, const typename QtPrivate::FunctionPointer<PointerToMemberFunction>::Object *receiver, PointerToMemberFunction method, Qt::ConnectionType type = Qt::AutoConnection)

Creates a connection of the given type from the state specified by scxmlStateName to method in the receiver object.

The receiver's method must take a boolean argument that indicates whether the state connected became active or inactive.

Returns a handle to the connection, which can be used later to disconnect.

typename QtPrivate::QEnableIf<!QtPrivate::FunctionPointer<Functor>::IsPointerToMemberFunction && !std::is_same<const char *, Functor>::value, QMetaObject::Connection>::Type QScxmlStateMachine::connectToState(const QString &scxmlStateName, Functor functor, Qt::ConnectionType type = Qt::AutoConnection)

Creates a connection of the given type from the state specified by scxmlStateName to functor.

The functor must take a boolean argument that indicates whether the state connected became active or inactive.

Returns a handle to the connection, which can be used later to disconnect.

typename QtPrivate::QEnableIf<!QtPrivate::FunctionPointer<Functor>::IsPointerToMemberFunction && !std::is_same<const char *, Functor>::value, QMetaObject::Connection>::Type QScxmlStateMachine::connectToState(const QString &scxmlStateName, const QObject *context, Functor functor, Qt::ConnectionType type = Qt::AutoConnection)

Creates a connection of the given type from the state specified by scxmlStateName to functor using context as context.

The functor must take a boolean argument that indicates whether the state connected became active or inactive.

Returns a handle to the connection, which can be used later to disconnect.

QScxmlDataModel *QScxmlStateMachine::dataModel() const

Returns the data model used by the state machine.

Note: Getter function for property dataModel.

See also setDataModel().

[static] QScxmlStateMachine *QScxmlStateMachine::fromData(QIODevice *data, const QString &fileName = QString())

Creates a state machine by reading from the QIODevice specified by data.

This method will always return a state machine. If errors occur while reading the SCXML file, fileName, the state machine cannot be started. The errors can be retrieved by calling the parseErrors() method.

See also parseErrors().

[static] QScxmlStateMachine *QScxmlStateMachine::fromFile(const QString &fileName)

Creates a state machine from the SCXML file specified by fileName.

This method will always return a state machine. If errors occur while reading the SCXML file, the state machine cannot be started. The errors can be retrieved by calling the parseErrors() method.

See also parseErrors().

bool QScxmlStateMachine::isActive(const QString &scxmlStateName) const

Returns true if the state specified by scxmlStateName is active, false otherwise.

Note: This function can be invoked via the meta-object system and from QML. See Q_INVOKABLE.

[protected] bool QScxmlStateMachine::isActive(int stateIndex) const

Returns true if the state with the ID stateIndex is active.

This method is part of the interface to the compiled representation of SCXML state machines. It should only be used internally and by state machines compiled from SCXML documents.

bool QScxmlStateMachine::isDispatchableTarget(const QString &target) const

Returns true if a message to target can be dispatched by this state machine.

Valid targets are:

• #_parent for the parent state machine if the current state machine is started by <invoke>
• #_internal for the current state machine
• #_scxml_sessionid, where sessionid is the session ID of the current state machine
• #_servicename, where servicename is the ID or name of a service started with <invoke> by this state machine

Note: This function can be invoked via the meta-object system and from QML. See Q_INVOKABLE.

bool QScxmlStateMachine::isRunning() const

Returns true if the state machine is running, false otherwise.

Note: Getter function for property running.

See also setRunning() and runningChanged().

[static] std::function<void (bool)> QScxmlStateMachine::onEntry(const QObject *, const char *receiver)

Returns a functor that accepts a boolean argument and calls the given method on receiver using QMetaObject::invokeMethod() if that argument is true and receiver has not been deleted, yet.

The given method must not accept any arguments. method is the plain method name, not enclosed in SIGNAL() or SLOT().

This is useful to wrap handlers for connectToState() that should only be executed when the state is entered.

[static] std::function<void (bool)> QScxmlStateMachine::onEntry(Functor)

Returns a functor that accepts a boolean argument and calls the given functor if that argument is true. The given functor must not accept any arguments.

This is useful to wrap handlers for connectToState() that should only be executed when the state is entered.

[static] std::function<void (bool)> QScxmlStateMachine::onEntry(const typename QtPrivate::FunctionPointer<PointerToMemberFunction>::Object *, PointerToMemberFunction receiver)

Returns a functor that accepts a boolean argument and calls the given method on receiver if that argument is true and the receiver has not been deleted, yet. The given method must not accept any arguments.

This is useful to wrap handlers for connectToState() that should only be executed when the state is entered.

[static] std::function<void (bool)> QScxmlStateMachine::onExit(const QObject *, const char *receiver)

Returns a functor that accepts a boolean argument and calls the given method on receiver using QMetaObject::invokeMethod() if that argument is false and receiver has not been deleted, yet.

The given method must not accept any arguments. method is the plain method name, not enclosed in SIGNAL(...) or SLOT(...).

This is useful to wrap handlers for connectToState() that should only be executed when the state is left.

[static] std::function<void (bool)> QScxmlStateMachine::onExit(Functor)

Returns a functor that accepts a boolean argument and calls the given functor if that argument is false. The given functor must not accept any arguments.

This is useful to wrap handlers for connectToState() that should only be executed when the state is left.

[static] std::function<void (bool)> QScxmlStateMachine::onExit(const typename QtPrivate::FunctionPointer<PointerToMemberFunction>::Object *, PointerToMemberFunction receiver)

Returns a functor that accepts a boolean argument and calls the given method on receiver if that argument is false and the receiver has not been deleted, yet. The given method must not accept any arguments.

This is useful to wrap handlers for connectToState() that should only be executed when the state is left.

void QScxmlStateMachine::setDataModel(QScxmlDataModel *model)

Sets the data model for this state machine to model. There is a 1:1 relation between state machines and models. After setting the model once you cannot change it anymore. Any further attempts to set the model using this method will be ignored.

Note: Setter function for property dataModel.

See also dataModel().

void QScxmlStateMachine::setRunning(bool running)

Starts the state machine if running is true, or stops it otherwise.

Note: Setter function for property running.

See also start(), stop(), isRunning(), and runningChanged().

QStringList QScxmlStateMachine::stateNames(bool compress = true) const

Retrieves a list of state names of all states.

When compress is true (the default), the states that contain child states will be filtered out and only the leaf states will be returned. When it is false, the full list of all states will be returned.

The returned list does not contain the states of possible nested state machines.

Note: The order of the state names in the list is the order in which the states occurred in the SCXML document.

Note: This function can be invoked via the meta-object system and from QML. See Q_INVOKABLE.

void QScxmlStateMachine::submitEvent(QScxmlEvent *event)

Submits the SCXML event event to the internal or external event queue depending on the priority of the event.

When a delay is set, the event will be queued for delivery after the timeout has passed. The state machine takes ownership of event and deletes it after processing.

Note: This function can be invoked via the meta-object system and from QML. See Q_INVOKABLE.

void QScxmlStateMachine::submitEvent(const QString &eventName)

A utility method to create and submit an external event with the specified eventName as the name.

Note: This function can be invoked via the meta-object system and from QML. See Q_INVOKABLE.

void QScxmlStateMachine::submitEvent(const QString &eventName, const QVariant &data)

A utility method to create and submit an external event with the specified eventName as the name and data as the payload data.

Note: This function can be invoked via the meta-object system and from QML. See Q_INVOKABLE.