import { Element, IValidatable, ISerializable } from '../base';
import { ISimpleQuantity } from 'fhirtypes/dist/r4/datatypes/ISimpleQuantity';
import { IElement } from 'fhirtypes/dist/r4/base';
import { SimpleQuantityBuilder } from '../../builders';
export declare class SimpleQuantity extends Element implements ISimpleQuantity, IValidatable, ISerializable {
    value?: number;
    unit?: string;
    system?: string;
    code?: string;
    _value?: IElement;
    _code?: IElement;
    _system?: IElement;
    _unit?: IElement;
    toJson(): any;
    toPrettyString(): string;
    toString(): string;
    constructor(args?: ISimpleQuantity);
    protected builderInstance(): SimpleQuantityBuilder;
    serialize(): string;
    validate(): {
        isValid: boolean;
        operationOutcome: import("fhirtypes/dist/r4").IOperationOutcome;
    };
}