feat: parse affordance title(s) and description(s)

lib/src/definitions/interaction_affordances/action.dart

@@ -14,12 +14,6 @@ import 'interaction_affordance.dart';
 
 /// Class representing an [Action] Affordance in a Thing Description.
 class Action extends InteractionAffordance {
-  /// The default title of this [Action].
-  String? title;
-
-  /// The default description of this [Action].
-  String? description;
-
   /// The schema of the [input] data this [Action] accepts.
   DataSchema? input;
 
@@ -31,6 +25,6 @@ class Action extends InteractionAffordance {
 
   /// Creates a new [Action] from a [json] object.
   Action.fromJson(Map<String, dynamic> json) : super([]) {
-    parseForms(json);
+    parseAffordanceFields(json);
   }
 }

lib/src/definitions/interaction_affordances/event.dart

@@ -13,17 +13,11 @@ import 'interaction_affordance.dart';
 
 /// Class representing an [Event] Affordance in a Thing Description.
 class Event extends InteractionAffordance {
-  /// The default title of this [Event].
-  String? title;
-
-  /// The default description of this [Event].
-  String? description;
-
   /// Creates a new [Event] from a [List] of [forms].
   Event(List<Form> forms) : super(forms);
 
   /// Creates a new [Event] from a [json] object.
   Event.fromJson(Map<String, dynamic> json) : super([]) {
-    parseForms(json);
+    parseAffordanceFields(json);
   }
 }

lib/src/definitions/interaction_affordances/interaction_affordance.dart

@@ -12,6 +12,18 @@ import '../form.dart';
 
 /// Base class for Interaction Affordances (Properties, Actions, and Events).
 abstract class InteractionAffordance {
+  /// The default [title] of this [InteractionAffordance].
+  String? title;
+
+  /// Multilanguage [titles] of this [InteractionAffordance].
+  Map<String, String>? titles;
+
+  /// The default [description] of this [InteractionAffordance].
+  String? description;
+
+  /// Multilanguage [descriptions] of this [InteractionAffordance].
+  Map<String, String>? descriptions;
+
   /// The basic [forms] which can be used for interacting with this resource.
   List<Form> forms;
 
@@ -21,14 +33,49 @@ abstract class InteractionAffordance {
   List<Form> augmentedForms = [];
 
   /// Parses [forms] represented by a [json] object.
-  void parseForms(Map<String, dynamic> json) {
+  void _parseForms(Map<String, dynamic> json) {
     for (final formJson in json["forms"]) {
       if (formJson is Map<String, dynamic>) {
         forms.add(Form.fromJson(formJson));
       }
     }
   }
 
+  Map<String, String>? _parseMultilangString(
+      Map<String, dynamic> json, String jsonKey) {
+    Map<String, String>? field;
+    final dynamic jsonEntries = json[jsonKey];
+    if (jsonEntries is Map<String, dynamic>) {
+      field = {};
+      for (final entry in jsonEntries.entries) {
+        final dynamic value = entry.value;
+        if (value is String) {
+          field[entry.key] = value;
+        }
+      }
+    }
+    return field;
+  }
+
+  /// Parses the [InteractionAffordance] contained in a [json] object.
+  void parseAffordanceFields(Map<String, dynamic> json) {
+    _parseForms(json);
+
+    final dynamic title = json["title"];
+    if (title is String) {
+      this.title = title;
+    }
+
+    titles = _parseMultilangString(json, "titles");
+
+    final dynamic description = json["description"];
+    if (description is String) {
+      this.description = description;
+    }
+
+    descriptions = _parseMultilangString(json, "descriptions");
+  }
+
   /// Creates a new [InteractionAffordance]. Accepts a [List] of [forms].
   InteractionAffordance(this.forms);
 }

lib/src/definitions/interaction_affordances/property.dart

@@ -23,12 +23,6 @@ class Property extends InteractionAffordance implements DataSchema {
   @override
   Object? defaultValue;
 
-  @override
-  String? description;
-
-  @override
-  Map<String, String>? descriptions;
-
   @override
   List<Object>? enumeration;
 
@@ -41,12 +35,6 @@ class Property extends InteractionAffordance implements DataSchema {
   @override
   bool? readOnly;
 
-  @override
-  String? title;
-
-  @override
-  Map<String, String>? titles;
-
   @override
   String? type;
 
@@ -61,7 +49,7 @@ class Property extends InteractionAffordance implements DataSchema {
 
   /// Creates a new [Property] from a [json] object.
   Property.fromJson(Map<String, dynamic> json) : super([]) {
-    parseForms(json);
+    parseAffordanceFields(json);
     parseDataSchemaJson(this, json);
   }
 }