adds an observer instance if it is not already in the set of observers for this observable . concode_field_sep Vector<Observer> m_Observers concode_field_sep void removeObservers concode_elem_sep void removeObserver concode_elem_sep void notifyObservers concode_elem_sep int getObserverCount
void function ( Observer arg0 ) { synchronized ( m_Observers ) { if ( ! m_Observers . contains ( arg0 ) ) { m_Observers . addElement ( arg0 ) ; } } }