import type { Handler, Topic, SubscriberToken, IPubSub } from '../../../types';
declare class StreamPubSub implements IPubSub {
    private recieiveQueue;
    private sendQueue;
    private _channel;
    private _channelSubscribed;
    private _topicHandlersMap;
    private _subscriberTokenMap;
    constructor(recieiveQueue?: any, sendQueue?: any);
    private _getChannel;
    private _getHandlers;
    private _subscribeChannel;
    /**
     * Publishes a topic asynchronously, passing the data to its subscribers.
     * Asynchronous publication helps in that the originator of the topics will not be blocked while consumers process them.
     * @param topic The topic's name
     * @param payload The data to be passed to its subscribers
     */
    publish(topic: string, payload: string): void;
    /**
     * Subscribe to events of interest with a specific topic name and a callback function, to be executed when the topic/event is observed.
     * @param topic The topic's name.
     * @param handler Callback function to execute on topic message, taking one argument: {string} payload. The payload passed when publishing a message to channel.
     * @return The subscriber's token
     */
    subscribe(topic: string, handler: Handler): SubscriberToken;
    /**
     * Checks if there are subscribers for a specific topic. If topic is not provided, checks if there is at least one subscriber.
     * @return true if the topic exist and has subscribers, otherwise false.
     */
    hasSubscribers(topic?: Topic): boolean;
    /**
     * @returns true if the topic exist and has been removed, or false if the topic does not exist.
     */
    unSubsribeByTopic(topic: Topic): boolean;
    /**
     * @returns true if the subscriber token exist and has been removed, or false the subscriber token does not exist.
     */
    unSubsribeByToken(token: SubscriberToken): boolean;
    /**
     * @returns true if the subscriber handler exist and has been removed, or false the subscriber handler does not exist.
     */
    unSubsribeByHandler(handler: Handler): boolean;
    clearAllSubscriptions(): void;
}
export declare const PubSub: StreamPubSub;
export {};