/**
 * Enumerates the logging levels.
 *
 * @enum {number}
 */
export declare enum LogLevel {
    /**
     * Fatal errors.
     */
    Fatal = 0,
    /**
     * Common errors.
     */
    Error = 1,
    /**
     * Warning information.
     */
    Warning = 2,
    /**
     * Common information.
     */
    Info = 3,
    /**
     * Debugging information.
     */
    Debug = 4,
    /**
     * Tracing information.
     */
    Trace = 5
}
/**
 * Base service for logging.
 *
 * @class Logger
 */
export declare class Logger {
    private _logLevel;
    /**
     * Logs the information at the provided level.
     *
     * @param {LogLevel | string} level The logging level.
     * @param {Error} exception The error that occured (may not be specified).
     * @param {string} messageFormat The message format.
     * @param {...any[]} args The arguments for the message format.
     * @memberof Logger
     */
    log(level: LogLevel | string, exception: Error | null | undefined, messageFormat: string, ...args: any[]): void;
    /**
     * Indicates whether logging at the indicated level is enabled.
     * @param {LogLevel | string} level The logging level.
     * @return true if enabled, false if not.
     */
    isEnabled(level: LogLevel | string): boolean;
    /**
     * Sets the logging level to the indicated one.
     *
     * @param {(LogLevel | string)} level The new log level.
     * @memberof Logger
     */
    setLevel(level: LogLevel | string): void;
    /**
     * Logs the event at the fatal level.
     *
     * @param {Error | string} event The event to be logged.
     * @param {...any[]} args The arguments for the event.
     * @memberof Logger
     */
    fatal(event: Error | string, ...args: any[]): void;
    /**
     * Logs the event at the error level.
     *
     * @param {Error | string} event The event to be logged.
     * @param {...any[]} args The arguments for the event.
     * @memberof Logger
     */
    error(event: Error | string, ...args: any[]): void;
    /**
     * Logs the event at the warning level.
     *
     * @param {Error | string} event The event to be logged.
     * @param {...any[]} args The arguments for the event.
     * @memberof Logger
     */
    warn(event: Error | string, ...args: any[]): void;
    /**
     * Logs the event at the information level.
     *
     * @param {Error | string} event The event to be logged.
     * @param {...any[]} args The arguments for the event.
     * @memberof Logger
     */
    info(event: Error | string, ...args: any[]): void;
    /**
     * Logs the event at the debug level.
     *
     * @param {Error | string} event The event to be logged.
     * @param {...any[]} args The arguments for the event.
     * @memberof Logger
     */
    debug(event: Error | string, ...args: any[]): void;
    /**
     * Logs the event at the trace level.
     *
     * @param {Error | string} event The event to be logged.
     * @param {...any[]} args The arguments for the event.
     * @memberof Logger
     */
    trace(event: Error | string, ...args: any[]): void;
    /**
     * Overridable method for writing to the log.
     *
     * @param {LogLevel} level The logging level.
     * @param {Error} exception The error that occured (may not be specified).
     * @param {string} messageFormat The message format.
     * @param {any[]} args The arguments for the message format.
     * @memberof Logger
     */
    protected write(level: LogLevel, exception: Error | null | undefined, messageFormat: string, args: any[]): void;
    private _log;
}