Example of Proxy Design Pattern

proxy.dart

import 'package:flutter/material.dart';

abstract class Proxy {
  Widget build(BuildContext context);
}

class SensitiveData implements Proxy {
  @override
  Widget build(BuildContext context) {
    return const Text("Password is 1234");
  }
}

class AccessChecker implements Proxy {
  const AccessChecker({
    required this.haveAccess,
    required this.sensitiveData,
  });

  final Proxy sensitiveData;
  final bool haveAccess;

  @override
  Widget build(BuildContext context) {
    return haveAccess
        ? sensitiveData.build(context)
        : const Text("You do not have access to this data");
  }
}