nsIObserverService

nsIObserverService

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Service allows a client listener (nsIObserver ) to register and unregister for notifications ofa specific string referenced topic. Service also provides a way to notify registered listeners and a way to enumerate registered client listeners

Methods

addObserver

Registers a given listener for a notifications regarding the specified topic.

Syntax:

void nsIObserverService::addObserver(
	in nsIObserver anObserver,in string aTopic,
	in boolean ownsWeak)  

Parameters:

anObserver: The interface pointer to the object which will receive notifications.

aTopic : The notification topic or subject.

ownsWeak: If set to FALSE , the nsIObserverService will hold a strong reference to anObserver . If set to TRUE and anObserver supports the nsIWeakReference interface, a weak reference will be held. Otherwise an error will be returned.

nsresult:

NS_OK if successful.

removeObserver

Unregisters a given listener from notifications regarding the specified topic.

Syntax:

void nsIObserverService::removeObserver(
	in nsIObserver anObserver,in string aTopic) 

Parameters:

anObserver: The interface pointer to the object which should stop receiving notifications.

aTopic: The notification topic or subject.

nsresult:

NS_OK if successful.

notifyObservers

Notifies all registered listeners of the given topic.

Syntax:

void nsIObserverService::notifyObservers(
	in nsISupports aSubject,in string aTopic,
	in wstring someData)  

Parameters:

aSubject: Notification specific interface pointer.

aTopic: The notification topic or subject.

someData: Notification specific wide string.

nsresult:

NS_OK if successful.

enumerateObservers

Returns an enumeration of all registered listeners.

See also: nsISimpleEnumerator .

Syntax:

nsISimpleEnumerator nsIObserverService::enumerateObservers(
	in string aTopic) 

Parameters:

aTopic: The notification topic or subject.

nsresult:

NS_OK if successful.