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Embedding Gecko API

nsIObserverService

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.
Written by:Ellen Evans | Comments, questions, complaints? Bug 143387
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