IlvGroupMediator Class Reference

Mediator between a 'Business Graphic Object' and its corresponding object in the application. More...

#include <ilviews/protos/grouplin.h>

Inheritance diagram for IlvGroupMediator:

List of all members.

Public Member Functions
	IlvGroupMediator (IlvGroup *presentation, IlAny object=0)
	Links an object of the application domain with its representation.
IlBoolean	changeValue (const IlvValue &val)
	Changes the object's value. Both the name and the new value are contained in val.
IlBoolean	changeValues (const IlvValue *values, IlUShort count)
	Updates the object when the user has changed the presentation.
void	getAccessors (const IlSymbol *const **, const IlvValueTypeClass *const **, IlUInt &) const
	Returns the names of all the accessors known by this object.
const char *	getName () const
	Returns the object name.
IlAny	getObject () const
	Returns the object linked to the current presentation.
IlvGroup *	getPresentation () const
	Returns the presentation currently linked to the object.
void	lock ()
	Locks the mediator.
IlBoolean	locked ()
	Guard against update loops that could occur if the representation attribute does not match the attribute of the object it represents.
IlvValue &	queryValue (IlvValue &val) const
	Queries the value designated by value from the object. Both the value and the value type are stored in value.
void	queryValues (IlvValue *values, IlUShort count) const
	Updates the presentation from the object values.
virtual void	setObject (IlAny arg, IlBoolean refresh=IlTrue)
	Sets the object to link to the presentation.
virtual void	setPresentation (IlvGroup *group, IlBoolean refresh=IlTrue)
	Sets the presentation that will allow the user to edit the object.
void	unlock ()
	Releases the lock.
virtual void	update (const IlSymbol *const *symbs=0, IlUInt count=0)
	Synchronizes the presentation with the object values.

---

Detailed Description

Mediator between a 'Business Graphic Object' and its corresponding object in the application.

Library: ilvproto

The IlvGroupMediator class allows you to link an application object to its corresponding presentation in a graphical user interface (GUI). The presentation is implemented as an IlvGroup. This class reads the values exported from the group and keeps synchronized its object and the group implementing its user interface. Synchronization is used to refer to the following:

• When, through accessors interpreting the user actions, one of the public attributes of the group is changed, the IlvGroupMediator is notified and updates the object to reflect the changes by calling the changeValues method.

• When the object changes and these changes need to be propagated to the presentation so that the user can see the changes, the IlvGroupMediator will call its queryValues method, which updates the values with data corresponding to the internal state of the object.

• Finally, whenever attributes change in the object, the application calls the update method to ensure that the presentation reflects these changes.

See the samples in the Views directory: samples/protos/inspector

See also:

IlvGroup

---

Constructor & Destructor Documentation

IlvGroupMediator::IlvGroupMediator	(	IlvGroup *	presentation,
		IlAny	object = 0
	)

Links an object of the application domain with its representation.

Creates an instance of IlvGroupMediator by linking its presentation with its object. presentation implements the presentation under the form of an IlvGroup while object is an object of the application domain.

Parameters:

	presentation	A group that implements the visual appearance of an object. This group will usually require attributes that match the attributes of its attached object.
	object	Any reference to an applicative object that must be presented to the user.
	object	A reference to any kind of object of the application represented by the presentation.

---

Member Function Documentation

IlBoolean IlvGroupMediator::changeValue

(

const IlvValue &

v

)

[virtual]

Changes the object's value. Both the name and the new value are contained in val.

Parameters:

v

The value to be set (both name and value).

Returns:

Whether the object considered the operation successful or not.

Reimplemented from IlvAccessible.

IlBoolean IlvGroupMediator::changeValues	(	const IlvValue *	values,
		IlUShort	count
	)			[virtual]

Updates the object when the user has changed the presentation.

This method must be overloaded. The implementation should read the values changed, update the internal state of the object to reflect these new values, and propagate these changes to other potential observers of the object. This method should start with if(locked()) return IlTrue; to avoid possible feedback loops between the object and its representation. You may also want to use the lock method to lock the IlvGroupMediator class before propagating the changes, and then use the unlock method when you have finished (to avoid unnecessary updates of the presentation).

Parameters:

	values	Values that have changed in the IlvGroup and should be reflected in the application object.
	count	Number of values.

Returns:

IlTrue if the change was successful.

Reimplemented from IlvAccessible.

void IlvGroupMediator::getAccessors	(	const IlSymbol *const **	a,
		const IlvValueTypeClass *const **	t,
		IlUInt &	c
	)			const [virtual]

Returns the names of all the accessors known by this object.

Subclasses of IlvAccessible must override this method by calling the static method DeclareAccessor for each accessor handled by the subclass. The returned arrays are filled by the method and must not be freed.

Parameters:

	a	Pointer to an array filled on return with the names of the accessors defined for the object.
	t	Pointer to an array filled on return with the type of each accessor.
	c	Number of accessors, set by the method.

Implements IlvAccessible.

const char* IlvGroupMediator::getName

(

)

const [virtual]

Returns the object name.

Returns:

The object name. This pointer must not be freed.

Implements IlvAccessible.

IlAny IlvGroupMediator::getObject

(

)

const

Returns the object linked to the current presentation.

Returns:

The object linked to the current presentation.

See also:

setObject.

IlvGroup* IlvGroupMediator::getPresentation

(

)

const

Returns the presentation currently linked to the object.

Returns:

The presentation currently linked to the object.

void IlvGroupMediator::lock

(

)

Locks the mediator.

Locks the IlvGroupMediator so that further changes will not be propagated to the object. This avoids infinite update loops between the object and its representation.

IlBoolean IlvGroupMediator::locked

(

)

Guard against update loops that could occur if the representation attribute does not match the attribute of the object it represents.

Returns:

IlTrue if the lock on the object has been set. This implies that changes are not propagated to the object or the group.

IlvValue& IlvGroupMediator::queryValue

(

IlvValue &

value

)

const [virtual]

Queries the value designated by value from the object. Both the value and the value type are stored in value.

Parameters:

value

The queried value name.

Returns:

The value passed in argument, set to the object value.

Reimplemented from IlvAccessible.

void IlvGroupMediator::queryValues	(	IlvValue *	values,
		IlUShort	count
	)			const [virtual]

Updates the presentation from the object values.

This method must be overloaded. The implementation should fill the values array with values representing the internal state of the object.

Parameters:

	values	Values to be changed in the IlvGroup.
	count	Number of values.

Reimplemented from IlvAccessible.

virtual void IlvGroupMediator::setObject	(	IlAny	arg,
		IlBoolean	refresh = IlTrue
	)			[virtual]

Sets the object to link to the presentation.

Parameters:

	arg	The object that is linked to the presentation.
	refresh	Can be set to IlFalse if you don't want an immediate refresh.

virtual void IlvGroupMediator::setPresentation	(	IlvGroup *	group,
		IlBoolean	refresh = IlTrue
	)			[virtual]

Sets the presentation that will allow the user to edit the object.

Parameters:

	group	The presentation that is linked to this object.
	refresh	Can be set to IlFalse if you don't want an immediate refresh.

Reimplemented in IlvProtoMediator.

void IlvGroupMediator::unlock

(

)

Releases the lock.

Releases the lock on the object, allowing further changes to be propagated.

virtual void IlvGroupMediator::update	(	const IlSymbol *const *	symbs = 0,
		IlUInt	count = 0
	)			[virtual]

Synchronizes the presentation with the object values.

Use this method whenever the object is changed from the application and the presentation is to be updated to reflect these changes. The optional list of symbols indicates what attributes have changed. It can be used to minimize refreshes of the representation.

Parameters:

	symbs	Array of attribute names that should be queried from the object and changed in the group serving as presentation. If symbs is NULL, all attributes that are notifying in the IlvGroup are queried from the object and changed in the presentation.
	count	Size of the symbs array.