Greatly improved deserialization from Json. No converters needed. Using a contract resolver to handle the way Unity needs objects instantiated.

Author: Jared Bienz

SpatialAlignment-Unity/Assembly-CSharp.csproj

@@ -829,8 +829,11 @@
     <Compile Include="Assets\HoloToolkit-Preview\SpectatorView\UnityARKitPlugin\Plugins\iOS\UnityARKit\NativeInterface\UnityARSessionNativeInterface.cs" />
     <Compile Include="Assets\SpatialAlignment\Persistence\INativePersistence.cs" />
     <Compile Include="Assets\SpatialAlignment\Persistence\ISpatialAlignmentStore.cs" />
+    <Compile Include="Assets\SpatialAlignment\Persistence\Json\AlignmentStrategyConverter.cs" />
     <Compile Include="Assets\SpatialAlignment\Persistence\Json\JsonStore.cs" />
+    <Compile Include="Assets\SpatialAlignment\Persistence\Json\SpatialContractResolver.cs" />
     <Compile Include="Assets\SpatialAlignment\Persistence\Json\SpatialFrameConverter.cs" />
+    <Compile Include="Assets\SpatialAlignment\Persistence\Json\UnityContractResolver.cs" />
     <Compile Include="Assets\SpatialAlignment\Persistence\Json\Vector3Converter.cs" />
     <Compile Include="Assets\SpatialAlignment\SpatialAlignmentManager.cs" />
     <Compile Include="Assets\SpatialAlignment\SpatialFrame.cs" />

SpatialAlignment-Unity/Assets/SpatialAlignment/Persistence/Json/AlignmentStrategyConverter.cs

@@ -0,0 +1,77 @@
+//
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license.
+//
+// MIT License:
+// Permission is hereby granted, free of charge, to any person obtaining
+// a copy of this software and associated documentation files (the
+// "Software"), to deal in the Software without restriction, including
+// without limitation the rights to use, copy, modify, merge, publish,
+// distribute, sublicense, and/or sell copies of the Software, and to
+// permit persons to whom the Software is furnished to do so, subject to
+// the following conditions:
+//
+// The above copyright notice and this permission notice shall be
+// included in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED ""AS IS"", WITHOUT WARRANTY OF ANY KIND,
+// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+//
+
+using Newtonsoft.Json;
+using Newtonsoft.Json.Converters;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using UnityEngine;
+
+namespace Microsoft.SpatialAlignment.Persistence.Json
+{
+    public class AlignmentStrategyConverter : CustomCreationConverter<IAlignmentStrategy>
+    {
+        public override IAlignmentStrategy Create(Type objectType)
+        {
+            throw new NotImplementedException();
+        }
+
+        //public override bool CanConvert(Type objectType)
+        //{
+        //    return typeof(IAlignmentStrategy).IsAssignableFrom(objectType);
+        //}
+
+        //public override bool CanWrite => false; // Only use for read operations, not write operations.
+
+        //public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
+        //{
+        //    // Existing object is a ???
+
+        //    return null;
+        //    //// Instantiate the component
+        //    //GameObject go = new GameObject();
+
+        //    //// Add a SpatialFrame to it
+        //    //SpatialFrame frame = go.AddComponent<SpatialFrame>();
+
+        //    //// Deserialize into the instance
+        //    //serializer.Populate(reader, frame);
+
+        //    //// Update the game object name to match
+        //    //go.name = frame.Id;
+
+        //    //// Return the frame
+        //    //return frame;
+        //}
+
+        //public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
+        //{
+        //    throw new NotImplementedException();
+        //}
+    }
+}

SpatialAlignment-Unity/Assets/SpatialAlignment/Persistence/Json/AlignmentStrategyConverter.cs.meta

@@ -52,8 +52,12 @@ private JsonSerializer CreateSerializer()
             // Make pretty
             settings.Formatting = Formatting.Indented;
 
+            // Use custom contract resolver (handles Unity-specific instantiation)
+            settings.ContractResolver = new SpatialContractResolver();
+
             // Add converters
-            settings.Converters.Add(new SpatialFrameConverter());
+            // settings.Converters.Add(new AlignmentStrategyConverter());
+            // settings.Converters.Add(new SpatialFrameConverter());
             settings.Converters.Add(new StringEnumConverter());
             settings.Converters.Add(new Vector3Converter());
 

SpatialAlignment-Unity/Assets/SpatialAlignment/Persistence/Json/JsonStore.cs

@@ -0,0 +1,73 @@
+//
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license.
+//
+// MIT License:
+// Permission is hereby granted, free of charge, to any person obtaining
+// a copy of this software and associated documentation files (the
+// "Software"), to deal in the Software without restriction, including
+// without limitation the rights to use, copy, modify, merge, publish,
+// distribute, sublicense, and/or sell copies of the Software, and to
+// permit persons to whom the Software is furnished to do so, subject to
+// the following conditions:
+//
+// The above copyright notice and this permission notice shall be
+// included in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED ""AS IS"", WITHOUT WARRANTY OF ANY KIND,
+// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+//
+
+using Newtonsoft.Json.Serialization;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Reflection;
+using System.Text;
+using System.Threading.Tasks;
+using UnityEngine;
+
+namespace Microsoft.SpatialAlignment.Persistence.Json
+{
+    /// <summary>
+    /// A Json.Net contract resolver with deserialization rules for
+    /// spatial alignment classes.
+    /// <remarks>
+    /// Whenever this resolver creates a <see cref="SpatialFrame"/>,
+    /// it sets that frame as the context for new objects to be
+    /// created under it.
+    /// </remarks>
+    public class SpatialContractResolver : UnityContractResolver
+    {
+        #region Overridables / Event Triggers
+        /// <inheritdoc />
+        protected override Component CreateComponent(Type objectType)
+        {
+            // Is it a frame?
+            bool isFrame = typeof(SpatialFrame).IsAssignableFrom(objectType);
+
+            // If it's a frame, the creation context should be a new object
+            if (isFrame) { CreationContext = null; }
+
+            // Let the base create the component
+            Component component = base.CreateComponent(objectType);
+
+            // Additional steps if this is a frame
+            if (isFrame)
+            {
+                // Set the frame as the context for the next set of
+                // behaviors to be attached to.
+                CreationContext = component.gameObject;
+            }
+
+            // Return the created component
+            return component;
+        }
+        #endregion // Overridables / Event Triggers
+    }
+}

SpatialAlignment-Unity/Assets/SpatialAlignment/Persistence/Json/SpatialContractResolver.cs

@@ -0,0 +1,109 @@
+//
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license.
+//
+// MIT License:
+// Permission is hereby granted, free of charge, to any person obtaining
+// a copy of this software and associated documentation files (the
+// "Software"), to deal in the Software without restriction, including
+// without limitation the rights to use, copy, modify, merge, publish,
+// distribute, sublicense, and/or sell copies of the Software, and to
+// permit persons to whom the Software is furnished to do so, subject to
+// the following conditions:
+//
+// The above copyright notice and this permission notice shall be
+// included in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED ""AS IS"", WITHOUT WARRANTY OF ANY KIND,
+// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+//
+
+using Newtonsoft.Json.Serialization;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Reflection;
+using System.Text;
+using System.Threading.Tasks;
+using UnityEngine;
+
+namespace Microsoft.SpatialAlignment.Persistence.Json
+{
+    /// <summary>
+    /// A Json.Net contract resolver that knows how to instantiate Unity objects
+    /// like <see cref="Component"/> and <see cref="MonoBehaviour"/>.
+    /// </summary>
+    /// <remarks>
+    /// This resolver is necessary because in Unity we can't just create behaviors
+    /// using their constructors, we must add them to game objects using
+    /// <see cref="GameObject.AddComponent(Type)">AddComponent</see>.
+    /// </remarks>
+    public class UnityContractResolver : DefaultContractResolver
+    {
+        #region Member Variables
+        private GameObject creationContext;
+        #endregion // Member Variables
+
+        #region Overridables / Event Triggers
+        /// <summary>
+        /// Instantiates a Unity <see cref="Component"/> (or <see cref="MonoBehaviour"/>).
+        /// </summary>
+        /// <param name="objectType">
+        /// The type of component to create.
+        /// </param>
+        /// <returns>
+        /// The created component.
+        /// </returns>
+        protected virtual Component CreateComponent(Type objectType)
+        {
+            // Use the existing creation context if found
+            // Otherwise, create a new GameObject to serve as the parent
+            GameObject parent = (creationContext ?? new GameObject());
+
+            // Instantiate the component
+            return parent.AddComponent(objectType);
+        }
+        #endregion // Overridables / Event Triggers
+
+        #region IContractResolver Overrides
+        protected override JsonObjectContract CreateObjectContract(Type objectType)
+        {
+
+            if (typeof(Component).IsAssignableFrom(objectType))
+            {
+                // Start with base contract
+                var contract = base.CreateObjectContract(objectType);
+
+                // Override to instantiate the component
+                contract.OverrideCreator = ((args) => CreateComponent(objectType));
+
+                // Return the new contract
+                return contract;
+            }
+            else
+            {
+                // Just use the base contract.
+                return base.CreateObjectContract(objectType);
+            }
+        }
+        #endregion // IContractResolver Overrides
+
+        #region Public Properties
+        /// <summary>
+        /// Gets or sets the <see cref="GameObject"/> that will be used as the
+        /// creation context.
+        /// </summary>
+        /// <remarks>
+        /// If set, this <see cref="GameObject"/> will be used to instantiate
+        /// components. Otherwise a new <see cref="GameObject"/> will be created
+        /// for each new component.
+        /// </remarks>
+        public GameObject CreationContext { get => creationContext; set => creationContext = value; }
+        #endregion // Public Properties
+    }
+}

SpatialAlignment-Unity/Assets/SpatialAlignment/Persistence/Json/SpatialContractResolver.cs.meta

@@ -23,6 +23,7 @@
 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 //
 
+using Microsoft.SpatialAlignment.Persistence.Json;
 using Newtonsoft.Json;
 using System;
 using System.Collections.Generic;
@@ -69,7 +70,18 @@ protected virtual void OnIdChanged()
         /// Gets the <see cref="IAlignmentStrategy"/> that is being used to align the frame.
         /// </summary>
         [DataMember]
-        public virtual IAlignmentStrategy AlignmentStrategy { get => GetComponent<IAlignmentStrategy>(); }
+        // [JsonProperty(ItemConverterType = typeof(AlignmentStrategyConverter))]
+        public virtual IAlignmentStrategy AlignmentStrategy
+        {
+            get
+            {
+                return GetComponent<IAlignmentStrategy>();
+            }
+            set
+            {
+                var v = value;
+            }
+        }
 
         /// <summary>
         /// Gets or sets a unique ID for the frame.