import { Element } from '../base/Element';
import { IDuration, IElement, QuantityComparatorType } from 'fhirtypes/dist/r4';
import { IValidatable } from '../base/IValidatable';
import { ISerializable } from '../base/ISerializable';
import { DurationBuilder } from '../../builders';
export declare class Duration extends Element implements IDuration, IValidatable, ISerializable {
    /**
     * @description The value of the measured amount. The value includes an implicit precision in the presentation of the value.
     */
    value?: number;
    /**
     * @description How the value should be understood and represented - whether the actual value is greater or less than the stated value due to measurement issues; e.g. if the comparator is "<" , then the real value is < stated value.
     */
    comparator?: QuantityComparatorType;
    /**
     * @description A human-readable form of the unit.
     */
    unit?: string;
    /**
     * @description The identification of the system that provides the coded form of the unit.
     */
    system?: string;
    /**
     * @description A computer processable form of the unit in some unit representation system.
     */
    code?: string;
    /**
     * @description Extensions for value
     */
    _value?: IElement;
    /**
     * @description Extensions for comparator
     */
    _comparator?: IElement;
    /**
     * @description Extensions for unit
     */
    _unit?: IElement;
    /**
     * @description Extensions for system
     */
    _system?: IElement;
    /**
     * @description Extensions for code
     */
    _code?: IElement;
    toJson(): any;
    toPrettyString(): string;
    toString(): string;
    constructor(args?: IDuration);
    protected builderInstance(): DurationBuilder;
    serialize(): string;
    validate(): {
        isValid: boolean;
        operationOutcome: import("fhirtypes/dist/r4").IOperationOutcome;
    };
}