question: retrieve the instance of the pseudo roster manager . concode_field_sep String GET_ALL_PSEUDO_ROSTERS concode_elem_sep String REMOVE_ROSTER concode_elem_sep PseudoRosterManager instance concode_elem_sep Logger Log concode_field_sep void removePseudoRoster concode_elem_sep List<Long> getRegistrations concode_elem_sep void shutdown concode_elem_sep PseudoRoster getPseudoRoster concode_elem_sep PseudoRoster getPseudoRoster concode_elem_sep PseudoRoster getPseudoRoster
target: PseudoRosterManager function ( ) { if ( instance == null ) { instance = new PseudoRosterManager ( ) ; } return instance ; }