code: @Override
  	public void modify(ResourceSnapshot resource) {
  		checkNotNull(resource,RESOURCE_CANNOT_BE_NULL);
  		checkArgument(resource instanceof DelegatedResourceSnapshot,"Unknown resource '%s'",resource.name());
  		checkState(this.status.equals(Status.ACTIVE),WRITE_SESSION_NOT_ACTIVE,status);
  		DelegatedResourceSnapshot delegatedResource=(DelegatedResourceSnapshot)resource;
  		delegatedResource.modify();
  	}
docs: {@inheritDoc}