question: public ScheduleItem addItem ( String type ) { _IdNumber ++ ; _sequenceNum ++ ; String id = _id + "c" + Integer . toString ( _IdNumber ) ; log . debug ( "Adding new item to ({}) id: {}" , getName ( ) , id ) ; ScheduleItem si = new ScheduleItem ( id , type ) ; si . setSequenceId ( _sequenceNum ) ; Integer old = Integer . valueOf ( _scheduleHashTable . size ( ) ) ; _scheduleHashTable . put ( si . getId ( ) , si ) ; setDirtyAndFirePropertyChange ( LISTCHANGE_CHANGED_PROPERTY , old , Integer . valueOf ( _scheduleHashTable . size ( ) ) ) ; si . addPropertyChangeListener ( this ) ; return si ; }
target:  Adds a car type to the end of this schedule