import { IElement, IPeriod } from 'fhirtypes/dist/r4';
import { PeriodBuilder } from '../../builders';
import { Element } from '../base/Element';
import { ISerializable } from '../base/ISerializable';
import { IValidatable } from '../base/IValidatable';
/**
 * @description Time range defined by start and end date/time.
 * @implements {IPeriod}
 * @property {string} id - Unique id for inter-element referencing
 * @property {IExtension[]} extension - Additional content defined by implementations
 * @property {string} start - Starting time with inclusive boundary
 * @property {string} end - End time with inclusive boundary, if not ongoing
 * @property {IElement} _start - Extension of start
 * @property {IElement} _end - Extension of end
 * @see {@link https://www.hl7.org/fhir/datatypes.html#Period Period}
 * @author Roberto Araneda
 */
export declare class Period extends Element implements IPeriod, IValidatable, ISerializable {
    /**
     * @description Starting time with inclusive boundary
     * @description A date, date-time or partial date (e.g. just year or year + month) as used in human communication. The format is YYYY, YYYY-MM, YYYY-MM-DD or YYYY-MM-DDThh:mm:ss+zz:zz
     * @description The time "24:00" is not allowed.
     * @example 2018, 1973-06, 1905-08-23, 2015-02-07T13:28:17-05:00 or 2017-01-01T00:00:00.000Z
     */
    start?: string;
    /**
     * @description End time with inclusive boundary, if not ongoing
     * @description A date, date-time or partial date (e.g. just year or year + month) as used in human communication. The format is YYYY, YYYY-MM, YYYY-MM-DD or YYYY-MM-DDThh:mm:ss+zz:zz
     * @example 2018, 1973-06, 1905-08-23, 2015-02-07T13:28:17-05:00 or 2017-01-01T00:00:00.000Z
     */
    end?: string;
    /**
     * @description Extension of start
     */
    _start?: IElement;
    /**
     * @description Extension of end
     */
    _end?: IElement;
    toJson(): any;
    toPrettyString(): string;
    toString(): string;
    validate(): {
        isValid: boolean;
        operationOutcome: import("fhirtypes/dist/r4").IOperationOutcome;
    };
    constructor(args?: IPeriod);
    protected builderInstance(): PeriodBuilder;
    serialize(): string;
}