METHOD FOR EFFECTIVELY UTILIZING EVENT STORAGE AREA IN HIERARCHICAL MANAGEMENT

PROBLEM TO BE SOLVED: To reuse an event storage area of a hierarchy that is lower than a hierarchy in the middle of processing by providing a redundant state node and surely making an upper state node an adjacent upper hierarchy. SOLUTION: An internal event is read from an event storage area 102-2 and state transition of a state node 100-2 is performed. An internal event is produced in an upper state node 100-3 with it. The event produced to the state node 100-3 is stored in an event storage area 102-3. Also, since an internal event to a redundant state node 300 exists in the event storage area, state transition is performed to the node 300 as well. An internal event is produced in the node 100-3 with it. The event produced to the node 100-3 is stored in the area 102-3. Here, an event storage area 100-1 is an unnecessary area for state determination processing on a hierarchy 2 because it is after all events are read.