private static void callback(long handle) {
        final C4DatabaseObserver obs = REVERSE_LOOKUP_TABLE.get(handle);
        if (obs != null && obs.listener != null) { obs.listener.callback(obs, obs.context); }
    }
private static void callback ( long handle ) { final C4DatabaseObserver obs = REVERSE_LOOKUP_TABLE . get ( handle ) ; if ( obs != null && obs . listener != null ) { obs . listener . callback ( obs , obs . context ) ; } }
Callback invoked by a database observer.
<p>
NOTE: Two parameters, observer and context, which are defined for iOS:
observer -> this instance
context ->  maintained in java layer