import { Cache } from './cache';
import type { CacheEntry } from './cache';
/**
 * Generic async cache interface.
 * @internal
 */
export interface AsyncCacheInterface<T> {
    /**
     * This is called when an entry is added to the cache.
     * @param key - The cache key to store the item under.
     * @param item - The destination alongside an expiration time to store in the cache.
     */
    set(key: string | undefined, item: CacheEntry<T>): Promise<void>;
    /**
     * This is called when an entry shall be retrieved from the cache.
     * @param key - The cache key the item is stored under.
     */
    get(key: string | undefined): Promise<T | undefined>;
    /**
     * This is called when checking if a given key occurs in the cache.
     * @param key - The cache key the item should be stored under, if available.
     */
    hasKey(key: string): Promise<boolean>;
    /**
     * This can be called to remove all existing entries from the cache.
     */
    clear(): Promise<void>;
}
/**
 * @internal
 * Async wrapper around Cache<T>.
 */
export declare class AsyncCache<T> implements AsyncCacheInterface<T> {
    cache: Cache<T>;
    constructor(defaultValidityTime?: number);
    /**
     * Specifies whether an entry with a given key is defined in cache.
     * @param key - The entry's key.
     * @returns A boolean value that indicates whether the entry exists in cache.
     */
    hasKey(key: string): Promise<boolean>;
    /**
     * Getter of cached entries.
     * @param key - The key of the entry to retrieve.
     * @returns The corresponding entry to the provided key if it is still valid, returns `undefined` otherwise.
     */
    get(key: string | undefined): Promise<T | undefined>;
    /**
     * Setter of entries in cache.
     * @param key - The entry's key.
     * @param item - The entry to cache.
     * @returns A promise to oid.
     */
    set(key: string | undefined, item: CacheEntry<T>): Promise<void>;
    /**
     * Clear all cached items.
     * @returns A promise to void.
     */
    clear(): Promise<void>;
}