/// <reference types="node" />
/// <reference types="node" />
import { Readable, Writable } from "stream";
import { PlantUmlPipeOptions } from "./plantuml_pipe_options";
/**
 * Class that wraps a PlantUML diagram generator running in pipe mode.
 */
export declare class PlantUmlPipe {
    /**
     * Process object for the PlantUML JAVA process that is spawned.
     */
    private readonly javaProcess;
    /**
     * Input stream of the object into which PlantUML code can be sent.
     */
    private readonly inputStream;
    /**
     * Output stream of the object into which the diagrams are written.
     */
    private readonly outputStream;
    /**
     * Collection of promise resolver functions used for the "process" method that returns a promise.
     */
    private readonly resolvers;
    /**
     * Creates a new PlantUML pipe.
     * @param userOptions Possible user defined options for the PlantUML generating pipe.
     */
    constructor(userOptions?: Readonly<PlantUmlPipeOptions>);
    /**
     * @returns The input stream into which to write the PlantUML code of the diagrams.
     */
    get in(): Writable;
    /**
     * @returns The output stream from which to read the generated PlantUML diagram images.
     */
    get out(): Readable;
    /**
     * Closes the input stream of the PlantUML diagram generator.
     */
    close(): void;
    /**
     * Resolves the currently first promise in the queue by calling its corresponding resolve function.
     * @param imageData The gnerated image data that is passed to the resolve function of the promise.
     */
    private readonly resolvePromise;
    /**
     * Generates a PlantUML diagram image from the given PlantUML code.
     * @param plantUml The PlantUML code.
     * @returns A promise with the data of the generated PlantUML diagram image.
     */
    process<T extends string | Readonly<Buffer>>(plantUml: string): Promise<T>;
}