import { Database } from "./database";
export interface PersistentQueueOptions {
    jobIsJson: boolean;
    cacheJobs: number;
}
export declare const DEFAULT_PERSISTENT_QUEUE_OPTIONS: PersistentQueueOptions;
export declare class QueuedJob<J> {
    id: number;
    created: number;
    job: J;
    private queue;
    returnAddress: string | undefined;
    reply?: Promise<J | undefined> | undefined;
    constructor(id: number, created: number, job: J, queue: PersistentQueue<J>, returnAddress: string | undefined, reply?: Promise<J | undefined> | undefined);
    delete(): void;
    done(): void;
}
export interface QueuedQueryJob<J> extends QueuedJob<J> {
    reply: Promise<J | undefined>;
}
export declare class PersistentQueue<J> {
    db: Database;
    private options;
    private cached;
    private nextId;
    private lastFetched;
    private waiting;
    currentLatency: number;
    queueSize: number;
    private running;
    private inProgress;
    constructor(db: Database, options?: Partial<PersistentQueueOptions>);
    close(): void;
    get outstandingCount(): number;
    get queueSizeOnDisk(): number;
    add(job: J, returnAddress?: string): QueuedJob<J>;
    _delete(job: QueuedJob<J>, scanForNext?: boolean): void;
    getNext(): Promise<QueuedJob<J>>;
    jobs(): AsyncIterable<QueuedJob<J>>;
    peekNext(): QueuedJob<J> | undefined;
    _done(job: QueuedJob<J>): void;
    private check;
}