import { IToXmlOptions } from './options';
import { IElement } from './util';
/**
 * Value object.
 */
export declare abstract class Value {
    /**
     * Value type.
     */
    static readonly TYPE: string;
    /**
     * Tag names.
     */
    static readonly TAG_NAMES: string[];
    /**
     * Value constructor.
     */
    constructor();
    /**
     * Value type.
     *
     * @returns Type string.
     */
    get type(): string;
    /**
     * Cast to specific type or null.
     *
     * @param Type Type constructor.
     * @returns This object or null.
     */
    castTo<T extends typeof Value>(Type: T): T['prototype'] | null;
    /**
     * Cast to specific type or throw.
     *
     * @param Type Type constructor.
     * @returns This object.
     */
    castAs<T extends typeof Value>(Type: T): T['prototype'];
    /**
     * Decode document from string.
     *
     * @param xml XML string.
     */
    fromXml(xml: string): void;
    /**
     * Decode value from element.
     *
     * @param element XML element.
     */
    abstract fromXmlElement(element: Readonly<IElement>): void;
    /**
     * Encode Value to string.
     *
     * @param options Options object.
     * @param depth Indent depth.
     * @returns Xml string.
     */
    abstract toXml(options?: Readonly<IToXmlOptions> | null, depth?: number): string;
}