Nullsafety update

AUTHORS

@@ -3,4 +3,5 @@
 #
 #   Name/Organization <email address>
 
-Adaptant Labs <[email protected]>
+Adaptant Labs <[email protected]>
+Stemco

CHANGELOG.md

@@ -1,3 +1,6 @@
+## 0.2.1
+- Migrated completely to nullsafety
+
 ## 0.2.0
 
 - Expose helpers for querying NHTSA DB and accessing extended vehicle information (requested by @ride4sun, issue #8)
@@ -10,6 +13,13 @@
 
 - Support VINs with 2-character manufacturer IDs in their WMI (reported by @huangkaichang, issue #7)
 - Fix Uri parsing for NHTSA DB REST API
+## 0.2.1-nullsafety
+
+- Support VINs with 2-character manufacturer IDs in their WMI (reported by @huangkaichang, issue #7)
+
+## 0.2.0-nullsafety
+
+- Migrate for null safety
 
 ## 0.1.3
 

example/vin_decoder_example.dart

@@ -1,8 +1,8 @@
-import 'package:vin_decoder/nhtsa.dart';
-import 'package:vin_decoder/vin_decoder.dart';
+import 'package:custom_vin_decoder/nhtsa.dart';
+import 'package:custom_vin_decoder/vin_decoder.dart';
 
 void main() async {
-  var vin = VIN(number: 'WP0ZZZ99ZTS392124', extended: true);
+  var vin = VIN(vin: 'WP0ZZZ99ZTS392124', extended: true);
 
   print('WMI: ${vin.wmi}');
   print('VDS: ${vin.vds}');
@@ -11,7 +11,7 @@ void main() async {
   print("Model year is " + vin.modelYear());
   print("Serial number is " + vin.serialNumber());
   print("Assembly plant is " + vin.assemblyPlant());
-  print("Manufacturer is " + vin.getManufacturer());
+  print("Manufacturer is " + (vin.getManufacturer() ?? ""));
   print("Year is " + vin.getYear().toString());
   print("Region is " + vin.getRegion());
   print("VIN string is " + vin.toString());
@@ -27,10 +27,10 @@ void main() async {
   print("Type is ${type}");
 
   var info = await NHTSA.decodeVin(vin.number);
-  print('Plant Country is ' + info.value('Plant Country'));
+  print('Plant Country is ' + (info?.value('Plant Country') ?? ""));
 
   var values = await NHTSA.decodeVinValues(vin.number);
-  print('Manufacturer from NHTSA DB is ' + values['Manufacturer']);
+  print('Manufacturer from NHTSA DB is ' + values?['Manufacturer']);
 
   var generated = VINGenerator().generate();
   print('Randomly Generated VIN is ${generated}');

lib/nhtsa.dart

@@ -1,5 +1,4 @@
 /// Support for querying NHTSA database by VIN.
-// @dart=2.1
 library nhtsa;
 
 export 'src/nhtsa_model.dart';

lib/src/nhtsa_model.dart

@@ -5,33 +5,34 @@ import 'dart:convert';
 // NHTSA Results not relevant for a specific vehicle can be either null or N/A
 const String _RESULT_NOT_APPLICABLE = 'Not Applicable';
 
+// ignore: avoid_classes_with_only_static_members
 /// A wrapper for the NHTSA REST API
 class NHTSA {
   static const String _uriBase = 'https://vpic.nhtsa.dot.gov/api/vehicles';
 
   /// Obtain information about a given [vin] from the NHTSA DB.
-  static Future<NHTSAVehicleInfo> decodeVin(String vin) async {
+  static Future<NHTSAVehicleInfo?> decodeVin(String vin) async {
     var path = _uriBase + '/DecodeVin/' + vin + '?format=json';
     final response = await http.get(Uri.parse(path));
 
     if (response.statusCode == 200) {
-      return NHTSAVehicleInfo.fromJson(jsonDecode(response.body));
+      return NHTSAVehicleInfo.fromJson(jsonDecode(response.body) as Map<String, dynamic>);
     }
 
     return null;
   }
 
   /// Obtain a map of key/value pairs containing known values for a given [vin]
-  static Future<Map<String, dynamic>> decodeVinValues(String vin) async {
+  static Future<Map<String, dynamic>?> decodeVinValues(String vin) async {
     var path = _uriBase + '/DecodeVinValues/' + vin + '?format=json';
     final response = await http.get(Uri.parse(path));
 
     // The DecodeVinValues endpoint returns a single Results object with all
     // variables and values as an array of encapsulated key/value pairs.
     // Manually unpack this in order to provide the caller a populated Dart map.
     if (response.statusCode == 200) {
-      Map<String, dynamic> data = jsonDecode(response.body);
-      Map<String, dynamic> map = data['Results'][0];
+      final Map<String, dynamic> data = jsonDecode(response.body) as Map<String, dynamic>;
+      final Map<String, dynamic> map = data['Results'][0] as Map<String, dynamic>;
       // Discard empty and not applicable entries from map
       map.removeWhere((key, value) =>
           value == null || value == _RESULT_NOT_APPLICABLE || value == '');
@@ -45,25 +46,27 @@ class NHTSA {
 /// The result of a single data point from the NHTSA DB for a specific variable.
 class NHTSAResult {
   /// The value associated with a given [variable] or [variableId]
-  String value;
+  String? value;
 
   /// The ID number associated with a given [value]
-  String valueId;
+  String? valueId;
 
   /// The variable name
-  String variable;
+  String? variable;
 
   /// The ID number of a given [variable]
-  int variableId;
+  int? variableId;
 
-  NHTSAResult({this.value, this.valueId, this.variable, this.variableId});
+  NHTSAResult({required this.value, required this.valueId, required this.variable, required this.variableId});
 
   /// Create a new [NHTSAResult] instance from a fixed JSON payload
-  NHTSAResult.fromJson(Map<String, dynamic> json) {
-    value = json['Value'];
-    valueId = json['ValueId'];
-    variable = json['Variable'];
-    variableId = json['VariableId'];
+  factory NHTSAResult.fromJson(Map<String, dynamic> json) {
+    return NHTSAResult(
+      value: json['Value'] as String?, 
+      valueId: json['ValueId'] as String?, 
+      variable: json['Variable'] as String?, 
+      variableId: json['VariableId'] as int?
+    );
   }
 
   @override
@@ -80,13 +83,11 @@ class NHTSAVehicleInfo {
   List<NHTSAResult> results = [];
 
   NHTSAVehicleInfo(
-      {this.count, this.message, this.searchCriteria, this.results});
+      {required this.count, required this.message, required this.searchCriteria, required this.results});
 
-  /// Create a new [NHTSAVehicleInfo] instance from a fixed JSON payload
-  NHTSAVehicleInfo.fromJson(Map<String, dynamic> json) {
-    count = json['Count'];
-    message = json['Message'];
-    searchCriteria = json['SearchCriteria'];
+  /// Create a new [NHTSAVehicleInfo] instance from a fixed JSON payload.
+  factory NHTSAVehicleInfo.fromJson(Map<String, dynamic> json) {
+    List<NHTSAResult> results = [];
     if (json['Results'] != null) {
       json['Results'].forEach((v) {
         if (v['Value'] != null &&
@@ -96,25 +97,34 @@ class NHTSAVehicleInfo {
         }
       });
     }
+    return NHTSAVehicleInfo(
+      count: (json['Count'] as int?) ?? 0,
+      message: json['Message'] as String? ?? "",
+      searchCriteria: json['SearchCriteria'],
+      results: results
+    );
   }
 
-  static String _normalizeStringValue(String s) {
+  static String? _normalizeStringValue(String? s) {
+    if (s == null){
+      return null;
+    }
     return s.splitMapJoin(' ',
         onNonMatch: (m) => StringUtils.capitalize(m.toLowerCase()));
   }
 
   /// Lookup the value of a variable by its [variableId] in the NHTSA DB results
-  String valueFromId(int variableId) {
+  String? valueFromId(int? variableId) {
     var result = results.singleWhere((e) => e.variableId == variableId,
-        orElse: () => null);
-    return result != null ? _normalizeStringValue(result.value) : null;
+        orElse: () => NHTSAResult(value: null, valueId: null, variable: null, variableId: null));
+    return _normalizeStringValue(result.value);
   }
 
   /// Lookup the value of a named [variable] in the NHTSA DB results
-  String value(String variable) {
+  String? value(String variable) {
     var result =
-        results.singleWhere((e) => e.variable == variable, orElse: () => null);
-    return result != null ? _normalizeStringValue(result.value) : null;
+        results.singleWhere((e) => e.variable == variable, orElse: () => NHTSAResult(value: null, valueId: null, variable: null, variableId: null));
+    return _normalizeStringValue(result.value);
   }
 
   @override

lib/src/vin_decoder_base.dart

@@ -2,8 +2,6 @@ import 'manufacturers.dart';
 import 'nhtsa_model.dart';
 import 'year_map.dart';
 
-import 'package:meta/meta.dart';
-
 class VIN {
   /// The VIN that the class was instantiated with.
   final String number;
@@ -21,14 +19,26 @@ class VIN {
   final bool extended;
   Map<String, dynamic> _vehicleInfo = {};
 
-  VIN({@required this.number, this.extended = false})
-      : wmi = normalize(number).substring(0, 3),
-        vds = normalize(number).substring(3, 9),
-        vis = normalize(number).substring(9, 17);
+  /// Private named constructor. Creates a new VIN. 
+  /// 
+  /// [wmi], [vds], and [vis] are populated based on [number]. 
+  VIN._({required this.number, required this.extended}) : 
+    wmi = number.substring(0, 3),
+    vds = number.substring(3, 9),
+    vis = number.substring(9, 17);
+
+  /// Creates a new VIN. 
+  /// 
+  /// This factory constructor makes sure the string is normallyed 
+  factory VIN({required String vin, bool extended = false}){
+    return VIN._(number: normalize(vin), extended: extended);
+  }
 
   /// Carry out VIN validation. A valid [number] must be 17 characters long
   /// and contain only valid alphanumeric characters.
-  bool valid([String number]) {
+  /// 
+  /// If a number is provided, validates that number. Otherwise, it validates the number this object was initialized with.
+  bool valid([String? number]) {
     String value = normalize(number != null ? number : this.number);
     return RegExp(r"^[a-zA-Z0-9]+$").hasMatch(value) && value.length == 17;
   }
@@ -39,7 +49,7 @@ class VIN {
 
   /// Obtain the encoded manufacturing year in YYYY format.
   int getYear() {
-    return yearMap[modelYear()];
+    return yearMap[modelYear()] ?? 2001;
   }
 
   /// Obtain the 2-character region code for the manufacturing region.
@@ -66,7 +76,9 @@ class VIN {
   }
 
   /// Get the full name of the vehicle manufacturer as defined by the [wmi].
-  String getManufacturer() {
+  /// 
+  /// If the full name cannot be found, returns null.
+  String? getManufacturer() {
     // Check for the standard case - a 3 character WMI
     if (manufacturers.containsKey(this.wmi)) {
       return manufacturers[this.wmi];
@@ -77,30 +89,33 @@ class VIN {
       if (manufacturers.containsKey(id)) {
         return manufacturers[id];
       } else {
-        return "Unknown (WMI: ${this.wmi.toUpperCase()})";
+        return null;
       }
     }
   }
 
   /// Returns the checksum for the VIN. Note that in the case of the EU region
   /// checksums are not implemented, so this becomes a no-op. More information
   /// is provided in ISO 3779:2009.
-  String getChecksum() {
-    return (getRegion() != "EU") ? normalize(this.number)[8] : null;
+  /// 
+  /// If the region is EU, returns null
+  String? getChecksum() {
+    return (getRegion() != "EU") ? this.number[8] : null;
   }
 
   /// Extract the single-character model year from the [number].
-  String modelYear() => normalize(this.number)[9];
+  String modelYear() => this.number[9];
 
   /// Extract the single-character assembly plant designator from the [number].
-  String assemblyPlant() => normalize(this.number)[10];
+  String assemblyPlant() => this.number[10];
 
   /// Extract the serial number from the [number].
-  String serialNumber() => normalize(this.number).substring(12, 17);
+  String serialNumber() => this.number.substring(12, 17);
 
+  /// Assigns the 
   Future<void> _fetchExtendedVehicleInfo() async {
     if (this._vehicleInfo.isEmpty && extended == true) {
-      this._vehicleInfo = await NHTSA.decodeVinValues(this.number);
+      this._vehicleInfo = await NHTSA.decodeVinValues(this.number) ?? {};
     }
   }
 
@@ -111,15 +126,24 @@ class VIN {
     return this._vehicleInfo['Make'];
   }
 
-  /// Get the Model of the vehicle from the NHTSA database if [extended] mode
-  /// is enabled.
+  /// Get the Make ID of a vehicle from the NHTSA database if the [extended] mode is enabled
+  Future<int> getMakeIdAsync() async {
+    await _fetchExtendedVehicleInfo();
+    return this._vehicleInfo["MakeID"];
+  }
+
+  /// Get the Model of the vehicle from the NHTSA database if [extended] mode is enabled.
   Future<String> getModelAsync() async {
     await _fetchExtendedVehicleInfo();
     return this._vehicleInfo['Model'];
   }
 
-  /// Get the Vehicle Type from the NHTSA database if [extended] mode is
-  /// enabled.
+  Future<String> getModelIdAsync() async {
+    await _fetchExtendedVehicleInfo();
+    return this._vehicleInfo['ModelID'];
+  }
+
+  /// Get the Vehicle Type from the NHTSA database if [extended] mode is enabled.
   Future<String> getVehicleTypeAsync() async {
     await _fetchExtendedVehicleInfo();
     return this._vehicleInfo['VehicleType'];