public GroupOptions addSort(@Nullable Sort sort) {

		if (sort == null) {
			return this;
		}

		if (this.sort == null) {
			this.sort = sort;
		} else {
			this.sort = this.sort.and(sort);
		}

		return this;
	}
public GroupOptions addSort ( @ Nullable Sort sort ) { if ( sort == null ) { return this ; } if ( this . sort == null ) { this . sort = sort ; } else { this . sort = this . sort . and ( sort ) ; } return this ; }
Adds {@link Sort} to instruct how to sort elements within a single group.

@param sort
@return