/**
 * An implementation of the observer pattern.
 *
 * @public
 * @extends {Disposable}
 */
export default class Event extends Disposable {
    /**
     * @param {*} sender - The object which owns the event.
     */
    constructor(sender: any);
    /**
     * Registers an event handler which will receive a notification when
     * {@link Event#fire} is called.
     *
     * @public
     * @param {Function} handler - The function which will be called each time the event fires. The first argument will be the event data. The second argument will be the event owner (i.e. sender).
     * @returns {Disposable}
     */
    public register(handler: Function): Disposable;
    /**
     * Removes registration for an event handler. That is, the handler will
     * no longer be called if the event fires.
     *
     * @public
     * @param {Function} handler
     */
    public unregister(handler: Function): void;
    /**
     * Removes all handlers from the event.
     *
     * @public
     */
    public clear(): void;
    /**
     * Triggers the event, calling all previously registered handlers.
     *
     * @public
     * @param {*} data - The data to pass each handler.
     */
    public fire(data: any): void;
    /**
     * Returns true if no handlers are currently registered.
     *
     * @public
     * @returns {boolean}
     */
    public getIsEmpty(): boolean;
    #private;
}
import Disposable from './../lang/Disposable.js';