ChangeListener which will be notified whenever the value
ObservableValue changes. If the same listener is added
more than once, then it will be notified more than once. That is, no
check is made to ensure uniqueness.
Note that the same actual
ChangeListener instance may be safely
registered for different
ObservableValue stores a strong reference to the listener
which will prevent the listener from being garbage collected and may
result in a memory leak. It is recommended to either unregister a
listener by calling
removeListener(ChangeListener) after use or to use an instance of
WeakChangeListener avoid this situation.
|The listener to register|
|if the listener is null|