code: void acceptOperation(Operation operation) throws MetadataUpdateException {
          log.trace("{}: Accept {}.", this.traceObjectId, operation);
          getOrCreateTransaction().acceptOperation(operation);
      }
docs: Phase 2/2 of processing an Operation. The Operation's effects are reflected in the pending UpdateTransaction.
  
  This method only has an effect on StorageOperations. It does nothing for MetadataOperations, regardless of whether
  the base Container Metadata is in Recovery Mode or not.
  
  @param operation The operation to accept.
  @throws MetadataUpdateException If the given operation was rejected given the current state of the metadata or
  most recent UpdateTransaction.
  @throws NullPointerException    If the operation is null.