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VR-Link API Documentation for DIS
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VR-Link API Documentation for DIS
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Instances of DtObservee are used to manage interest in this object by other objects, i.e. More...
Collaboration diagram for DtObservee:Public Types | |
| enum | DtWhyNotifyObserver { DtPendingDeleteOfYourObserved, DtDeleteOfYourObserved } |
| The observed object calls DtAbsNotifyObserver::notifyFromObserved() with the following values to notify the observer of crucial information. More... | |
Public Member Functions | |
| DtObservee () | |
| default constructor | |
| virtual | ~DtObservee () |
| destructor Observers should be notified before an object begins its destruction. | |
| DtObservee (const DtObservee &orig) | |
| copy constructor Maintains what was observing this object. | |
| DtObservee & | operator= (const DtObservee &orig) |
| assignment operator Maintains what was observing this object. | |
| virtual bool | registerObservedBy (DtAbsNotifyObserver *observer) |
| Register observation of this object by another. | |
| virtual bool | deRegisterObservedBy (DtAbsNotifyObserver *observer) |
| Deregister observation of this object by another. | |
| virtual void | notifyAllObservers (const DtWhyNotifyObserver &why) |
| Notify all observers with a status. | |
Static Public Member Functions | |
| static void | destroy (DtObservee *object) |
| Destroy object. | |
Protected Member Functions | |
| void | internalNotifyAllObservers (const DtWhyNotifyObserver &why) |
| Notify all observers with a status. | |
Protected Attributes | |
| DtList | myObservedByNotifiers |
| List of DtAbsNotifyObserver's which are used when observing this object. | |
| bool | myNotifiedPendingDelete |
Instances of DtObservee are used to manage interest in this object by other objects, i.e.
this object is being watched. This class forms the basis of all smart observation since only this class knows when it goes away, so it must tell watchers. Watchers can not smartly observe an object otherwise. This class uses DtAbsNotifyObserver to inform an observer that it is going away. Since DtAbsNotifyObserver is the critical component of notification, watchers do not have any derivation requirement (i.e. they can have no base class). The derivation requirement is that a derived DtAbsNotifyObserver is created which knows how to call out to the watcher class.
Objects of class DtObservee can be observed/pointed at/watched by essentially any other class because it uses class DtAbsNotifyObserver to notify the observer when an instance is deleted. A single instance of DtObservee can be watched by multiple instances of multiple classes.
The observed object calls DtAbsNotifyObserver::notifyFromObserved() with the following values to notify the observer of crucial information.
| DtPendingDeleteOfYourObserved |
This value is used from destroy() to let the observers of this observed object know the object they are observing is about to be destroyed (i.e. deleted). This allows the observers to examine the observed object for any information one last time before the object is deleted. Observers do not need to deregister themselves, and they should no longer try to observe the deleted object or reference it after handling this notification, i.e. they should remove it from their list of items they are observing. |
| DtDeleteOfYourObserved |
This value is used from the base class destructor if the DtPendingDeleteOfYourObserved status was not used. It is used as a failsafe to let observers know the object they are observing is in the process of being destroyed (i.e. deleted). Observers should not examine the observed object for any information since it is almost entirely deconstructed. Observers do not need to deregister themselves, and they should no longer try to observe the deleted object or reference it i.e. they should remove it from their list of items they are observing. |
default constructor
| virtual DtObservee::~DtObservee | ( | ) | [virtual] |
destructor Observers should be notified before an object begins its destruction.
Unfortunately, there is no way to mandate that this happen other than to rely on programming discipline to put a call to notify in every derived destructor.
The static member destroy() was implemented to provide notification of pending delete and then deletion and is the preferred method of deleting an object of this class.
If a programmer uses delete directly on an object of this class rather than using destroy(), it is the programmer's obligation to make sure notification goes out to observers before the object begins to be destroyed.
If notification does not go out of pending destruction, this destructor will send notification of destruction in process, but the observers must not examine the object in this case.
| DtObservee::DtObservee | ( | const DtObservee & | orig | ) |
copy constructor Maintains what was observing this object.
| virtual bool DtObservee::deRegisterObservedBy | ( | DtAbsNotifyObserver * | observer | ) | [virtual] |
Deregister observation of this object by another.
Returns DtFalse if the observer has not already been registered.
| static void DtObservee::destroy | ( | DtObservee * | object | ) | [static] |
Destroy object.
Notifies observers of pending destruction and then deletes the object. Caller should not access object again.
| void DtObservee::internalNotifyAllObservers | ( | const DtWhyNotifyObserver & | why | ) | [protected] |
Notify all observers with a status.
Non-virtual since meant to be called from dtor.
| virtual void DtObservee::notifyAllObservers | ( | const DtWhyNotifyObserver & | why | ) | [virtual] |
Notify all observers with a status.
Default calls internalNotifyAllObservers().
| DtObservee& DtObservee::operator= | ( | const DtObservee & | orig | ) |
assignment operator Maintains what was observing this object.
| virtual bool DtObservee::registerObservedBy | ( | DtAbsNotifyObserver * | observer | ) | [virtual] |
Register observation of this object by another.
Returns DtFalse if the observer has already been registered.
bool DtObservee::myNotifiedPendingDelete [protected] |
DtList DtObservee::myObservedByNotifiers [protected] |
List of DtAbsNotifyObserver's which are used when observing this object.
