import { Observable } from 'rxjs';
import { TaskInterface } from './definitions';
export declare class CancelableTask<T> implements TaskInterface<T> {
    private operation;
    private _canceled;
    private _executed;
    private _subject;
    get isCanceled(): boolean;
    constructor(operation: () => Observable<T>);
    /**
     * If canceled is called before the execute => do nothing
     * otherwise reject pending request
     * If canceled is called more than once, do nothing
     */
    cancel(withError?: Error): void;
    /**
     * If execute is called after cancel => return Operation cancelled exception
     * If already executing, return the current execution promise
     */
    execute(): Observable<T>;
    toObservable(): Observable<T>;
}