交 kiosk 主动对象 互 1: request(count performance) 4: offer( seat-list) 视 buy(seats) 图 8: confirm(seats, cost) at-list: =lock( count) 6: claim(seats) 被动对象 协 ck (seat-list) ticketseller dDd: Performance DB <<local>>db 作 暂时链 图 2: db: =findDB(performance) 多对象 bertormanceguide Performance交 互 视 图 二 ： 协 作 图 暂时链 <<local>>db dbs 多对象 被动对象 消息 7: unlock(seat-list) kiosk ticketSeller performanceGuide Dd:PerformanceDB :PerformanceDB 1:request(count,performance) 4:offer(seat-list) 5:buy(seats) 8:confirm(seats,cost) 3: seat-list:=lock(count) 6: claim(seats) 2: db:=findDB(performance) 主动对象 链