/**
 * @class Queue
 * This class provides a TypeScript implementation of a Queue (FIFO Structure).
 */
export declare class Queue<T> {
    private intHead?;
    private intTail?;
    private iintLength;
    constructor(...values: T[]);
    /**
     *
     * Creates a Application object using a JSON string
     * @param {String} json - JSON string.
     * @returns {Application} - Application object.
     * @memberof Queue
     */
    iterator(): IterableIterator<T>;
    [Symbol.iterator](): IterableIterator<T>;
    get head(): T | undefined;
    get tail(): T | undefined;
    get length(): number;
    insert(val: T, previousItem: T, checkDuplicates?: boolean): boolean;
    append(val: T, checkDuplicates?: boolean): boolean;
    prepend(val: T, checkDuplicates?: boolean): boolean;
    remove(val: T): T | undefined;
    removeHead(): T | undefined;
    removeTail(): T | undefined;
    first(num: number): T[];
    toArray(): T[];
    get front(): T | undefined;
    enqueue(val: T): void;
    dequeue(): T | undefined;
    private isDuplicate;
}
export declare class QueueItem<T> {
    value: T;
    next?: QueueItem<T>;
    prev?: QueueItem<T>;
    constructor(val: T);
}