Jazz Up Your C# Code

#region License
// Copyright (c) 2007 James Newton-King
//
// 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.
#endregion

using System;
using Newtonsoft.Json.Utilities;

namespace Newtonsoft.Json.Converters
{
  /// <summary>
  /// Create a custom object
  /// </summary>
  /// <typeparam name="T"></typeparam>
  public abstract class CustomCreationConverter<T> : JsonConverter
  {
    /// <summary>
    /// Writes the JSON representation of the object.
    /// </summary>
    /// <param name="writer">The <see cref="JsonWriter"/> to write to.</param>
    /// <param name="value">The value.</param>
    /// <param name="serializer">The calling serializer.</param>
    public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
    {
      throw new NotSupportedException("CustomCreationConverter should only be used while deserializing.");
    }

    /// <summary>
    /// Reads the JSON representation of the object.
    /// </summary>
    /// <param name="reader">The <see cref="JsonReader"/> to read from.</param>
    /// <param name="objectType">Type of the object.</param>
    /// <param name="existingValue">The existing value of object being read.</param>
    /// <param name="serializer">The calling serializer.</param>
    /// <returns>The object value.</returns>
    public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
    {
      if (reader.TokenType == JsonToken.Null)
        return null;

      T value = Create(objectType);
      if (value == null)
        throw new JsonSerializationException("No object created.");

      serializer.Populate(reader, value);
      return value;
    }

    /// <summary>
    /// Creates an object which will then be populated by the serializer.
    /// </summary>
    /// <param name="objectType">Type of the object.</param>
    /// <returns></returns>
    public abstract T Create(Type objectType);

    /// <summary>
    /// Determines whether this instance can convert the specified object type.
    /// </summary>
    /// <param name="objectType">Type of the object.</param>
    /// <returns>
    /// 	<c>true</c> if this instance can convert the specified object type; otherwise, <c>false</c>.
    /// </returns>
    public override bool CanConvert(Type objectType)
    {
      return typeof (T).IsAssignableFrom(objectType);
    }

    /// <summary>
    /// Gets a value indicating whether this <see cref="JsonConverter"/> can write JSON.
    /// </summary>
    /// <value>
    /// 	<c>true</c> if this <see cref="JsonConverter"/> can write JSON; otherwise, <c>false</c>.
    /// </value>
    public override bool CanWrite
    {
      get { return false; }
    }
  }
}