/**
 * @packageDocumentation
 * @module @verdigris/nitrous
 */
/**
 * Abstract base class required for implementing a cache driver.
 */
export default abstract class Driver {
    /**
     * Returns whether the connection to the underlying backend is closed.
     */
    abstract get isClosed(): boolean;
    /**
     * Returns whether the driver is connected to the underlying backend.
     */
    abstract isConnected(): Promise<boolean>;
    /**
     * Lists all keys.
     */
    abstract keys(): Promise<string[]>;
    /**
     * Gets whether the key exists in cache.
     * @param key {string}
     */
    abstract has(key: string): Promise<boolean>;
    /**
     * Gets the cached value at key.
     * @param key {string}
     */
    abstract get(key: string): Promise<any>;
    /**
     * Sets a value to be cached at key.
     * @param key {string}
     * @param value {any}
     * @param ttl {number} time-to-live in seconds
     */
    abstract set(key: string, value: any, ttl?: number): Promise<boolean>;
    /**
     * Gets the time-to-live of the key in seconds.
     * @param key {string}
     */
    abstract ttl(key: string): Promise<number>;
    /**
     * Sets the expiry duration (in seconds) for a given key.
     * @param key {string}
     * @param ttl {number} time-to-live in seconds
     */
    abstract expire(key: string, ttl: number): Promise<boolean>;
    /**
     * Delete a key.
     * @param key {string}
     */
    abstract delete(keys: string | string[]): Promise<number>;
    /**
     * Closes connection or ends cache timeouts depending on underlying driver.
     */
    abstract close(): Promise<boolean>;
}
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