Class to make a snapshot of the digraph and to restrore to it later.
The newly added nodes and arcs can be removed using the restore() function.
- Note
- After you restore a state, you cannot restore a later state, in other word you cannot add again the arcs deleted by restore() using another one Snapshot instance.
- Warning
- If you do not use correctly the snapshot that can cause either broken program, invalid state of the digraph, valid but not the restored digraph or no change. Because the runtime performance the validity of the snapshot is not stored.