import type { NullableCallback } from '../../Contracts';
declare const QueryParameter_base: (abstract new (...args: import("../../Contracts").Args) => {
    acceptsNullValues: boolean;
    nullValidator: NullableCallback;
    nullable(nullable?: boolean, validator?: NullableCallback): any;
    nullValues(nullValidator: NullableCallback): any;
    isNullable(): boolean;
    isValidNullValue(value: import("../../Contracts").AnyValue): boolean;
    valueIsConsideredNull(value: import("../../Contracts").AnyValue): boolean;
}) & {
    new (): {};
};
export default abstract class QueryParameter extends QueryParameter_base {
    /**
     * Get the query parameter key name.
     */
    abstract key(): string;
    nullable(nullable?: boolean, validator?: NullableCallback | undefined): this;
}
export {};