added StaticJsonConverter

MLEM.Data/Json/JsonConverters.cs

@@ -12,7 +12,7 @@ namespace MLEM.Data.Json {
         /// An array of all of the <see cref="JsonConverter"/>s that are part of MLEM.Data
         /// </summary>
         public static readonly JsonConverter[] Converters = typeof(JsonConverters).Assembly.GetExportedTypes()
-            .Where(t => t.IsSubclassOf(typeof(JsonConverter)))
+            .Where(t => t.IsSubclassOf(typeof(JsonConverter)) && !t.IsGenericType)
             .Select(t => t.GetConstructor(Type.EmptyTypes).Invoke(null)).Cast<JsonConverter>().ToArray();
 
         /// <summary>

MLEM.Data/Json/StaticJsonConverter.cs

@@ -0,0 +1,62 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Reflection;
+using Newtonsoft.Json;
+
+namespace MLEM.Data.Json {
+    /// <summary>
+    /// A <see cref="JsonConverter{T}"/> that doesn't actually serialize the object, but instead serializes the name given to it by the underlying <see cref="Dictionary{T,T}"/>. 
+    /// Optionally, the name of a <see cref="Dictionary{TKey,TValue}"/> can be passed to this converter when used in the <see cref="JsonConverterAttribute"/> by passing the arguments for the <see cref="StaticJsonConverter{T}(string,string)"/> constructor as <see cref="JsonConverterAttribute.ConverterParameters"/>.
+    /// </summary>
+    /// <typeparam name="T">The type of the object to convert</typeparam>
+    public class StaticJsonConverter<T> : JsonConverter<T> {
+
+        private readonly Dictionary<string, T> entries;
+        private readonly Dictionary<T, string> inverse;
+
+        /// <summary>
+        /// Creates a new static json converter using the given underlying <see cref="Dictionary{T,T}"/>.
+        /// </summary>
+        /// <param name="entries">The dictionary to use</param>
+        public StaticJsonConverter(Dictionary<string, T> entries) {
+            this.entries = entries;
+            this.inverse = entries.ToDictionary(kv => kv.Value, kv => kv.Key);
+        }
+
+        /// <summary>
+        /// Creates a new static json converter by finding the underlying <see cref="Dictionary{TKey,TValue}"/> from the given type and member name
+        /// </summary>
+        /// <param name="typeName">The name of the type that the dictionary is in</param>
+        /// <param name="memberName">The name of the dictionary itself</param>
+        public StaticJsonConverter(string typeName, string memberName) :
+            this(GetEntries(typeName, memberName)) {
+        }
+
+        /// <inheritdoc />
+        public override void WriteJson(JsonWriter writer, T value, JsonSerializer serializer) {
+            if (!this.inverse.TryGetValue(value, out var key))
+                throw new InvalidOperationException($"Cannot write {value} that is not a registered entry");
+            writer.WriteValue(key);
+        }
+
+        /// <inheritdoc />
+        public override T ReadJson(JsonReader reader, Type objectType, T existingValue, bool hasExistingValue, JsonSerializer serializer) {
+            var val = reader.Value?.ToString();
+            if (val == null)
+                return default;
+            this.entries.TryGetValue(val, out var ret);
+            return ret;
+        }
+
+        private static Dictionary<string, T> GetEntries(string typeName, string memberName) {
+            const BindingFlags flags = BindingFlags.Instance | BindingFlags.Static | BindingFlags.Public | BindingFlags.NonPublic;
+            var type = Type.GetType(typeName) ?? throw new ArgumentException($"Type {typeName} does not exist", nameof(typeName));
+            var value = type.GetProperty(memberName, flags)?.GetValue(null) ?? type.GetField(memberName, flags)?.GetValue(null);
+            if (value == null)
+                throw new ArgumentException($"There is no property or field value for name {memberName}", nameof(memberName));
+            return value as Dictionary<string, T> ?? throw new InvalidCastException($"{value} is not of expected type {typeof(T)}");
+        }
+
+    }
+}