/*!
 * Copyright (c) 2020 Ville de Montreal. All rights reserved.
 * Licensed under the MIT license.
 * See LICENSE file in the project root for full license information.
 */
import { ITimeProvider } from '../time/ITimeProvider';
/**
 *  A simple generic cache implementation that can expire entries using a ttl.
 *  Note that the ttl cleanup will happen only when modifying the cache,
 *  but not when reading entries.
 */
export declare class Cache<T> {
    private readonly timeProvider;
    private readonly entries;
    /**
     *  Creates a new instance of a Cache
     *  @param timeProvider the time provider used to know when the ttl expires.
     */
    constructor(timeProvider: ITimeProvider);
    /**
     *  finds an entry in the cache
     *  @param key the key used to find the entry
     *  @returns either the associated value or undefined.
     */
    get(key: string): T | undefined;
    /**
     *  add or edit a cache entry
     *  @param key the key used to store the value
     *  @param value the value associated to the key
     *  @param ttl a number of seconds to keep the value available
     */
    set(key: string, value: T, ttl: number): void;
    /**
     * delete an existing cache entry.
     * Note that it is safe to delete an entry that doesn't exist.
     * @param key the key used to find and delete the entry
     */
    delete(key: string): void;
    private hasExpired;
    private deleteExpiredEntries;
}