import { Extension } from '../extension/extension';
import { MetadataInfo } from '../metadata/metadata';
export declare abstract class ExtensionGroup {
    constructor(name: string);
    static onInit: undefined | ((manifest: MetadataInfo, property: MetadataInfo) => void);
    static createInstance(name: string): ExtensionGroup;
    static destroyInstance(_extensionGroup: ExtensionGroup): void;
    private _onInit;
    onInit(_manifest: MetadataInfo, _properties: MetadataInfo): Promise<void>;
    private _onCreateExtension;
    abstract onCreateExtension(): Promise<Extension[]> | Extension[];
    private _onDeleteExtension;
    abstract onDeleteExtension(_extensions: (Extension | null)[]): Promise<void> | void;
    private dumpDirtyProp;
    name: string;
    addonFolder: string | undefined;
}