A template subject filter. More...

#include <SubjectFilterTemplate.h>

Inheritance diagram for Qtilities::Core::SubjectFilterTemplate:

[legend]

Signals
void	modificationStateChanged (bool is_modified) const
	Implement this function as a signal when implementing the object.
Signals inherited from Qtilities::Core::AbstractSubjectFilter
void	monitoredPropertyChanged (const char property_name, QList< QObject > objects=QList< QObject * >())
	A signal which is emitted as soon as a monitored property of the observer or any of the installed subject filters changed.
void	propertyChangeFiltered (const char property_name, QList< QObject > objects=QList< QObject * >())
	A signal which is emitted as soon as an property change event is filtered.

Public Member Functions
AbstractSubjectFilter::EvaluationResult	evaluateAttachment (QObject obj, QString rejectMsg=0, bool silent=false) const
	Evaluates the attachment of a new subject to the filter's observer context. Use this function to check how an attachment will be handled.
AbstractSubjectFilter::EvaluationResult	evaluateDetachment (QObject obj, QString rejectMsg=0) const
	Evaluates the detachment of a subject from the filter's observer context. Use this function to check how an detachment will be handled.
QString	filterName () const
	Returns the name of the subject filter.
void	finalizeAttachment (QObject *obj, bool attachment_successful, bool import_cycle=false)
	Finalize the attachment of a the subject to the filter's observer context.
void	finalizeDetachment (QObject *obj, bool detachment_successful, bool subject_deleted=false)
	Finalize the detachment of a subject from the filter's observer context.
bool	initializeAttachment (QObject obj, QString rejectMsg, bool import_cycle=false)
	Initialize the attachment of a new subject to the filter's observer context.
bool	initializeDetachment (QObject obj, QString rejectMsg=0, bool subject_deleted=false)
	Initialize the detachment of a subject from the filter's observer context.
QStringList	monitoredProperties () const
	This function returns a QStringList with the names of all the properties which are monitored by this subject filter.
QStringList	reservedProperties () const
	This function returns a QStringList with the names of all the reserved properties of this subject filter.
Public Member Functions inherited from Qtilities::Core::AbstractSubjectFilter
virtual bool	isModificationStateMonitored () const
	Get if this subject filter's modification state is monitored by its observer context.
Observer *	observerContext () const
	Returns the observer context that this subject filter is attached to.
virtual void	setIsModificationStateMonitored (bool is_monitored)
	Set if this subject filter's modification state is monitored by its observer context.
virtual bool	setObserverContext (Observer *observer_context)
	Set the observer context for the subject filter. A subject filter is not usable when an observer context to operate in has not been set.
Public Member Functions inherited from Qtilities::Core::Interfaces::IExportable
quint32	applicationExportVersion () const
	Returns the application export version currently used by all your application's classes.
virtual void	clearExportTask ()
	Clears the export task.
IExportable *	duplicate (QString error_msg=0, int properties_to_copy=0, ExportResultFlags result_flags=0) const
	Function which will create a duplicate (copy) of this object.
virtual ExportResultFlags	exportBinary (QDataStream &stream) const
	Allows exporting to a QDataStream.
virtual ITask *	exportTask () const
	Gets the task which must be used to log import/export information to.
Qtilities::ExportVersion	exportVersion () const
	Returns the export version currently used by all Qtilities classes.
virtual ExportResultFlags	exportXml (QDomDocument doc, QDomElement object_node) const
	Allows exporting to an XML document. A reference to the QDomElement to which the object's information must be added is provided, along with a reference to the QDomDocument.
virtual ExportResultFlags	importBinary (QDataStream &stream, QList< QPointer< QObject > > &import_list)
	Allows importing and reconstruction of the object state from information provided in a QDataStream.
virtual ExportResultFlags	importXml (QDomDocument doc, QDomElement object_node, QList< QPointer< QObject > > &import_list)
	Allows importing and reconstruction of data from information provided in a XML document. A reference to the QDomElement which contains the object's information is provided, along with a reference to the QDomDocument.
bool	isExportable () const
	Gets if this object must be part of it's parents' exports.
virtual void	setApplicationExportVersion (quint32 version)
	Sets the application export version currently used by all your application's classes.
virtual void	setExportTask (ITask *task)
	Sets the task which must be used to log import/export information to.
virtual void	setExportVersion (Qtilities::ExportVersion version)
	Returns the export version currently used by all Qtilities classes.
virtual void	setIsExportable (bool new_is_exportable)
	Sets if this object must be part of it's parents' exports.
Public Member Functions inherited from Qtilities::Core::Interfaces::IObjectBase
QString	objectOriginID () const
	Allows interfaces to provide some sort of source identification.
void	setObjectOriginID (const QString &object_origin_id)
	Allows setting of the object source ID of this interface implementation.
Public Member Functions inherited from Qtilities::Core::Interfaces::IModificationNotifier
virtual void	setModificationState (bool new_state, NotificationTargets notification_targets=NotifyListeners, bool force_notifications=false)=0
	Sets the modification state of the object. Returns true if it was successfull.

Protected Member Functions
bool	handleMonitoredPropertyChange (QObject obj, const char property_name, QDynamicPropertyChangeEvent *propertyChangeEvent)
	Function which should react to QDynamicPropertyChangeEvents on properties which are reserved by the subject filter.
InstanceFactoryInfo	instanceFactoryInfo () const
	The instance factory information which must be used when the exported object is reconstructed during an import.
bool	isModified () const
	Indicates the modification state of the object.
QObject *	objectBase ()
	Returns the QObject* base of the interface.
const QObject *	objectBase () const
	Returns a const QObject* base of the interface.
ExportModeFlags	supportedFormats () const
	Provides information about the export format(s) supported by your implementation of IExportable.

Additional Inherited Members
Public Types inherited from Qtilities::Core::AbstractSubjectFilter
enum	EvaluationResult { Allowed, Conditional, Rejected }
	Enumeration which defines the possible results of subject filter evaluation operations. More...
Public Types inherited from Qtilities::Core::Interfaces::IExportable
enum	ExportMode { None = 0, Binary = 1, XML = 2 }
	Possible export modes that an implementation of IExportable can support. More...
enum	Result { Complete = 0, Incomplete = 1, Failed = 2, FailedContinue = 4, VersionTooNew = 8, VersionTooOld = 16, VersionSupported = 32, SuccessResult = Complete \| Incomplete \| VersionSupported, FailedResult = Failed \| FailedContinue \| VersionTooNew \| VersionTooOld }
	The possible results of an export/import operation. More...
Public Types inherited from Qtilities::Core::Interfaces::IModificationNotifier
enum	NotificationTarget { NotifyNone = 0, NotifyListeners = 1, NotifySubjects = 2 }
	The targets which should be notified when the state of the object implementing this interface changes. More...
Protected Attributes inherited from Qtilities::Core::AbstractSubjectFilter
bool	filter_is_modification_state_monitored
	Indicates if the modification state of the filter is monitored by it's observer context.
Observer *	observer
	The observer context to which the subject filter is attached.

Detailed Description

A template subject filter.

Creating custom subject filters is an easy task if you understand how the initialization and finalization diagrams shown in the Subject filters section of the Observers article work. The SubjectFilterTemplate class should be used as a starting point when creating new subject filters. The new filter class needs to inherit from Qtilities::Core::AbstractSubjectFilter and reimplement the virtual abstract functions in order to work. The source code of the subject filters which comes as part of Qtilities is a good place to start when looking for examples of filter implementations.

Member Function Documentation

Qtilities::Core::AbstractSubjectFilter::EvaluationResult Qtilities::Core::SubjectFilterTemplate::evaluateAttachment	(	QObject *	obj,
		QString *	rejectMsg = `0`,
		bool	silent = `false`
	)		const

virtual

Evaluates the attachment of a new subject to the filter's observer context. Use this function to check how an attachment will be handled.

Parameters:

obj	The object to be evaluated
rejectMsg	Provides a reject message when the evaluation failed.
silent	When true, the attachment must be done in a silent way. That is, it should not show any dialogs. This is usefull when objects must be attached to observers without calling exec() on a dialog (such as the user input dialog for NamingPolicyFilters) which can lead to crashes when for example attaching objects inside an event filter. For more information on this topic see Unpredictable exec().

Returns:: AbstractSubjectFilter::EvaluationResult indicating the result of the evaluation.

Note:: By default AbstractSubjectFilter::Allowed is returned by the base class.

Reimplemented from Qtilities::Core::AbstractSubjectFilter.

Qtilities::Core::AbstractSubjectFilter::EvaluationResult Qtilities::Core::SubjectFilterTemplate::evaluateDetachment	(	QObject *	obj,
		QString *	rejectMsg = `0`
	)		const

virtual

Evaluates the detachment of a subject from the filter's observer context. Use this function to check how an detachment will be handled.

Parameters:

obj	The object to be evaluated
rejectMsg	Provides a reject message when the evaluation failed.

Returns:: AbstractSubjectFilter::EvaluationResult indicating the result of the evaluation.

Note:: By default AbstractSubjectFilter::Allowed is returned by the base class.

Reimplemented from Qtilities::Core::AbstractSubjectFilter.

void Qtilities::Core::SubjectFilterTemplate::finalizeAttachment	(	QObject *	obj,
		bool	attachment_successful,
		bool	import_cycle = `false`
	)

virtual

Finalize the attachment of a the subject to the filter's observer context.

Note:: When attachment_successful is true, the object will already be attached to the observer context.

Parameters:

obj	The object to be added.
import_cycle	Indicates if the attachment call was made during an observer import cycle. In such cases the subject filter must not add exportable properties to the object since these properties will be added from the import source. Also, it is not neccesarry to validate the context in such cases.
attachment_successful	True if the attachment was successful, false otherwise.

Note:: By default does nothing in the base class.

Reimplemented from Qtilities::Core::AbstractSubjectFilter.

void Qtilities::Core::SubjectFilterTemplate::finalizeDetachment	(	QObject *	obj,
		bool	detachment_successful,
		bool	subject_deleted = `false`
	)

virtual

Finalize the detachment of a subject from the filter's observer context.

Parameters:

obj	The object to be detached.
detachment_successful	True if the detachment was successfull, false otherwise.
subject_deleted	Indicates if the detachment operation is happening because the subject was deleted. This allows for optimization inside implementations of this function.

Note:: By default does nothing in the base class.

Reimplemented from Qtilities::Core::AbstractSubjectFilter.

bool Qtilities::Core::SubjectFilterTemplate::handleMonitoredPropertyChange	(	QObject *	obj,
		const char *	property_name,
		QDynamicPropertyChangeEvent *	propertyChangeEvent
	)

protectedvirtual

Function which should react to QDynamicPropertyChangeEvents on properties which are reserved by the subject filter.

As soon as a subject is attached to an observer the observer installs a event filter on the subject which monitors dynamic property changes. When a dynamic property change event is received, the observer will route the event to the appropriate subject filter and call this function on the subject filter. Thus, this function will only be called when the property_name is a reserved property of the subject filter.

Parameters:

obj	The object on which the property change took place.
property_name	The property name which changed.
propertyChangeEvent	The QDynamicPropertyChangeEvent which triggered the event.

Returns:: Return true if the event should be filtered (thus, the event will not be allowed to finish and the property will not change), false otherwise when the change event should be allowed (thus, the event will not be filtered and the property will change if not filtered by any other subject filters).

Note:: By default false is returned by the base class.

See also:: monitoredProperties()

Reimplemented from Qtilities::Core::AbstractSubjectFilter.

bool Qtilities::Core::SubjectFilterTemplate::initializeAttachment	(	QObject *	obj,
		QString *	rejectMsg,
		bool	import_cycle = `false`
	)

virtual

Initialize the attachment of a new subject to the filter's observer context.

Note:: The object is not yet attached to the observer context when this function is called.

Parameters:

obj	The object to be added.
import_cycle	Indicates if the attachment call was made during an observer import cycle. In such cases the subject filter must not add exportable properties to the object since these properties will be added from the import source. Also, it is not neccesarry to validate the context in such cases.

Returns:: Return true if the attachment is allowed, false otherwise.; True if the attachment was successfully initialized, false otherwise.

Note:: By default true is returned by the base class.

Reimplemented from Qtilities::Core::AbstractSubjectFilter.

bool Qtilities::Core::SubjectFilterTemplate::initializeDetachment	(	QObject *	obj,
		QString *	rejectMsg = `0`,
		bool	subject_deleted = `false`
	)

virtual

Initialize the detachment of a subject from the filter's observer context.

Parameters:

obj	The object to be detached.
rejectMsg	A reject message when the initialization fails.
subject_deleted	Indicates if the detachment operation is happening because the subject was deleted. This allows for optimization inside implementations of this function.

Returns:: True if the detachment is allowed, false otherwise.

Note:: By default true is returned by the base class.

Reimplemented from Qtilities::Core::AbstractSubjectFilter.

Qtilities::Core::InstanceFactoryInfo Qtilities::Core::SubjectFilterTemplate::instanceFactoryInfo ( ) const

protectedvirtual

The instance factory information which must be used when the exported object is reconstructed during an import.

For more information see The IExportable interface, what does it have to do with factories?.

Reimplemented from Qtilities::Core::Interfaces::IExportable.

void Qtilities::Core::SubjectFilterTemplate::modificationStateChanged ( bool is_modified ) const

virtualsignal

Implement this function as a signal when implementing the object.

Because this interface does not use the Q_OBJECT macro, you cannot connect to this signal directly. Instead you need to connect to the signal on the base object implementing this interface as follows:

connect(iface->objectBase(),SIGNAL(modificationStateChanged(bool)),SLOT(yourSlot(bool)));

Implements Qtilities::Core::Interfaces::IModificationNotifier.

QStringList Qtilities::Core::SubjectFilterTemplate::monitoredProperties ( ) const

virtual

This function returns a QStringList with the names of all the properties which are monitored by this subject filter.

Monitored properties are all properties that you use on your subject filter that does not appear in the reservedProperties() list. All of these properties will be monitored by the observer context in which the subject filter is installed. The property change events will be delivered to handleMonitoredPropertyChange().

When property changes are valid, the monitoredPropertyChanged() signal is emitted as soon as the property change is completed.

Note:: By default an empty QStringList() is returned by the base class.

See also:: handleMonitoredPropertyChange(), monitoredPropertyChanged()

Reimplemented from Qtilities::Core::AbstractSubjectFilter.

const QObject* Qtilities::Core::SubjectFilterTemplate::objectBase ( ) const

inlineprotectedvirtual

Returns a const QObject* base of the interface.

This function can be used in const methods, but make sure that you don't modify things that should stay const. An example where this is used is when we want to get a property on an object in a const method. This is a const operation.

Implements Qtilities::Core::Interfaces::IObjectBase.

QStringList Qtilities::Core::SubjectFilterTemplate::reservedProperties ( ) const

virtual

This function returns a QStringList with the names of all the reserved properties of this subject filter.

Reserved properties are internal properties that cannot be changed. The observer will filter any attempted changes to these properties. To check if a property is reserved, see the Permisson attribute in the property documentation. All Qtilities properties are defined in the Qtilities::Core::Properties namespace.

Note:: By default an empty QStringList() is returned by the base class.

Reimplemented from Qtilities::Core::AbstractSubjectFilter.

Qtilities::Core::Interfaces::IExportable::ExportModeFlags Qtilities::Core::SubjectFilterTemplate::supportedFormats ( ) const

protectedvirtual

Provides information about the export format(s) supported by your implementation of IExportable.

Note:: It is important to note that you need to check the exportVersion() when you return the supported formats.

Reimplemented from Qtilities::Core::Interfaces::IExportable.

Signals

Public Member Functions

Protected Member Functions

Additional Inherited Members

Detailed Description

Member Function Documentation