Newtonsoft.Json\Converters\CustomCreationConverter.cs

#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;

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; }

    }

  }

}