import { ConflictException } from '@nestjs/common';
/**
 * DuplicateException
 *
 * Custom exception extending NestJS's `ConflictException`.
 * This should be thrown when an operation attempts to create or register
 * an entity that violates a uniqueness constraint or already exists in the system.
 *
 * Typical scenarios include:
 * - Attempting to register a username or email already in use
 * - Inserting database records that violate unique constraints
 * - Uploading or creating resources with duplicate identifiers
 *
 * Returning a standardized `409 Conflict` response helps API consumers
 * distinguish duplication errors from other kinds of client-side mistakes.
 */
export declare class DuplicateException extends ConflictException {
    /**
     * Creates a new `DuplicateException`.
     *
     * @param {string} [message] - Optional custom error message describing
     * the specific duplication issue. Defaults to a standardized message if omitted.
     */
    constructor(message?: string);
}
/**
 * ApiDuplicateResponse
 *
 * Swagger documentation decorator for `409 Conflict` responses caused
 * by duplicate resource creation attempts. Applying this decorator
 * ensures that the generated API docs communicate uniqueness constraints
 * and possible error conditions clearly to consumers.
 *
 * @param {string} [description] - Optional custom description of the duplication error.
 * Defaults to a standardized message if omitted.
 * @returns {MethodDecorator} - Swagger method decorator for documenting conflict responses.
 */
export declare function ApiDuplicateResponse(description?: string): MethodDecorator;