TF-233 Add mailbox name validator

lib/features/mailbox_creator/domain/exceptions/verify_name_exception.dart

@@ -0,0 +1,33 @@
+
+import 'package:equatable/equatable.dart';
+
+abstract class VerifyNameException extends Equatable implements Exception {
+  static const EmptyName = 'The name cannot be empty!';
+  static const DuplicatedName = 'The name already exists!';
+  static const NameContainSpecialCharacter = 'The name cannot contain special characters';
+
+  final String? message;
+
+  VerifyNameException(this.message);
+}
+
+class EmptyNameException extends VerifyNameException {
+  EmptyNameException() : super(VerifyNameException.EmptyName);
+
+  @override
+  List<Object> get props => [];
+}
+
+class DuplicatedNameException extends VerifyNameException {
+  DuplicatedNameException() : super(VerifyNameException.DuplicatedName);
+
+  @override
+  List<Object> get props => [];
+}
+
+class SpecialCharacterException extends VerifyNameException {
+  SpecialCharacterException() : super(VerifyNameException.NameContainSpecialCharacter);
+
+  @override
+  List<Object> get props => [];
+}