/**
 * Used to set specific HTTP status code when result returned by a controller action is equal to null.
 * Must be applied on a controller action.
 */
export declare function OnNull(code: number): Function;
/**
 * Used to set specific HTTP status code when result returned by a controller action is equal to null.
 * Must be applied on a controller action.
 */
export declare function OnNull(error: Function): Function;