public void addIfNotPresent(Annotation ann){
  if (_annotations == null || !_annotations.containsKey(ann.annotationType())) {
    _add(ann);
  }
}

public void addIfNotPresent ( Annotation ann ) { if ( _annotations == null || ! _annotations . containsKey ( ann . annotationType ( ) ) ) { _add ( ann ) ; } }
method called to add specified annotation in the map , but only if it didn ' t yet exist .
