/// <reference types="node" />
import { BaseEmitter } from './baseEmitter';
import { IDataEvent, IExecutionResult, ISettings, IStatusEvent, ITraceableAction } from './dataEmitter';
import { LoggerFacade } from './loggerFacade';
import { IService } from './maestro';
export interface IPollingSettings {
    interval: number;
}
/**
 * A base class that handles the scheduling of a polled fetch
 * to collect information and emit it
 */
export declare abstract class PollingEmitter extends BaseEmitter implements IService {
    protected _interval: number;
    protected _intervalTimer?: ReturnType<typeof setInterval>;
    protected _lastDataEvent?: IDataEvent;
    protected _lastStatusEvent?: IStatusEvent;
    /**
       *
       * @param {string} id
       * @param {string} name
       * @param {string} desc
       * @param {number} interval
       * @param {LoggerFacade|undefined} logger
       */
    constructor(id: string, name: string, desc: string, _interval: number, logger?: LoggerFacade | undefined);
    /**
       * Execute the poll and emit the result
       * @return {Promise<void>}
       */
    protected pollExecutor(): Promise<void>;
    /**
       * Start polling
       */
    startPolling(): void;
    /**
       * Stop polling
       */
    stopPolling(): void;
    /**
       * Start polling
       * @return {Promise<void>}
       */
    start(): Promise<void>;
    /**
       * Stop Polling
       * @return {Promise<void>}
       */
    stop(): Promise<void>;
    /**
       * probe current data
       * @return {IDataEvent}
       */
    probeCurrentData(): Promise<IDataEvent>;
    /**
       * probe the status
       * @return {IStatusEvent}
       */
    probeStatus(): Promise<IStatusEvent>;
    /**
       * set settings
       * @param {ISettings} settings
       * @return {Promise<IExecutionResult>}
       */
    applySettings(settings: ISettings & ITraceableAction & IPollingSettings): Promise<IExecutionResult>;
    /**
     * Poll the resource
     */
    abstract poll(): Promise<unknown>;
    /**
     * Clean up timers used for polling
     */
    dispose(): void;
}
/**
 * Polls a data source but only emits data events
 * when the data changes
 */
export declare abstract class DeltaPollingEmitter extends PollingEmitter {
    /**
       * Execute the poll and emit the result if there has been a change
       * @return {Promise<void>}
       */
    protected pollExecutor(): Promise<void>;
    /**
     * Check if the data event includes changes
     * @param {IDataEvent} evt
     */
    abstract hasChanged(evt: IDataEvent): boolean;
}