Newtonsoft.Json\Linq\Extensions.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;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using Newtonsoft.Json.Utilities;

using System.Collections;

using System.Globalization;

namespace Newtonsoft.Json.Linq

{

  /// <summary>

  /// Contains the LINQ to JSON extension methods.

  /// </summary>

  public static class Extensions

  {

    /// <summary>

    /// Returns a collection of tokens that contains the ancestors of every token in the source collection.

    /// </summary>

    /// <typeparam name="T">The type of the objects in source, constrained to <see cref="JToken"/>.</typeparam>

    /// <param name="source">An <see cref="IEnumerable{T}"/> of <see cref="JToken"/> that contains the source collection.</param>

    /// <returns>An <see cref="IEnumerable{T}"/> of <see cref="JToken"/> that contains the ancestors of every node in the source collection.</returns>

    public static IJEnumerable<JToken> Ancestors<T>(this IEnumerable<T> source) where T : JToken

    {

      ValidationUtils.ArgumentNotNull(source, "source");

      return source.SelectMany(j => j.Ancestors()).AsJEnumerable();

    }

    //TODO

    //public static IEnumerable<JObject> AncestorsAndSelf<T>(this IEnumerable<T> source) where T : JObject

    //{

    //  ValidationUtils.ArgumentNotNull(source, "source");

    //  return source.SelectMany(j => j.AncestorsAndSelf());

    //}

    /// <summary>

    /// Returns a collection of tokens that contains the descendants of every token in the source collection.

    /// </summary>

    /// <typeparam name="T">The type of the objects in source, constrained to <see cref="JContainer"/>.</typeparam>

    /// <param name="source">An <see cref="IEnumerable{T}"/> of <see cref="JToken"/> that contains the source collection.</param>

    /// <returns>An <see cref="IEnumerable{T}"/> of <see cref="JToken"/> that contains the descendants of every node in the source collection.</returns>

    public static IJEnumerable<JToken> Descendants<T>(this IEnumerable<T> source) where T : JContainer

    {

      ValidationUtils.ArgumentNotNull(source, "source");

      return source.SelectMany(j => j.Descendants()).AsJEnumerable();

    }

    //TODO

    //public static IEnumerable<JObject> DescendantsAndSelf<T>(this IEnumerable<T> source) where T : JContainer

    //{

    //  ValidationUtils.ArgumentNotNull(source, "source");

    //  return source.SelectMany(j => j.DescendantsAndSelf());

    //}

    /// <summary>

    /// Returns a collection of child properties of every object in the source collection.

    /// </summary>

    /// <param name="source">An <see cref="IEnumerable{T}"/> of <see cref="JObject"/> that contains the source collection.</param>

    /// <returns>An <see cref="IEnumerable{T}"/> of <see cref="JProperty"/> that contains the properties of every object in the source collection.</returns>

    public static IJEnumerable<JProperty> Properties(this IEnumerable<JObject> source)

    {

      ValidationUtils.ArgumentNotNull(source, "source");

      return source.SelectMany(d => d.Properties()).AsJEnumerable();

    }

    /// <summary>

    /// Returns a collection of child values of every object in the source collection with the given key.

    /// </summary>

    /// <param name="source">An <see cref="IEnumerable{T}"/> of <see cref="JToken"/> that contains the source collection.</param>

    /// <param name="key">The token key.</param>

    /// <returns>An <see cref="IEnumerable{T}"/> of <see cref="JToken"/> that contains the values of every node in the source collection with the given key.</returns>

    public static IJEnumerable<JToken> Values(this IEnumerable<JToken> source, object key)

    {

      return Values<JToken, JToken>(source, key).AsJEnumerable();

    }

    /// <summary>

    /// Returns a collection of child values of every object in the source collection.

    /// </summary>

    /// <param name="source">An <see cref="IEnumerable{T}"/> of <see cref="JToken"/> that contains the source collection.</param>

    /// <returns>An <see cref="IEnumerable{T}"/> of <see cref="JToken"/> that contains the values of every node in the source collection.</returns>

    public static IJEnumerable<JToken> Values(this IEnumerable<JToken> source)

    {

      return source.Values(null);

    }

    /// <summary>

    /// Returns a collection of converted child values of every object in the source collection with the given key.

    /// </summary>

    /// <typeparam name="U">The type to convert the values to.</typeparam>

    /// <param name="source">An <see cref="IEnumerable{T}"/> of <see cref="JToken"/> that contains the source collection.</param>

    /// <param name="key">The token key.</param>

    /// <returns>An <see cref="IEnumerable{T}"/> that contains the converted values of every node in the source collection with the given key.</returns>

    public static IEnumerable<U> Values<U>(this IEnumerable<JToken> source, object key)

    {

      return Values<JToken, U>(source, key);

    }

    /// <summary>

    /// Returns a collection of converted child values of every object in the source collection.

    /// </summary>

    /// <typeparam name="U">The type to convert the values to.</typeparam>

    /// <param name="source">An <see cref="IEnumerable{T}"/> of <see cref="JToken"/> that contains the source collection.</param>

    /// <returns>An <see cref="IEnumerable{T}"/> that contains the converted values of every node in the source collection.</returns>

    public static IEnumerable<U> Values<U>(this IEnumerable<JToken> source)

    {

      return Values<JToken, U>(source, null);

    }

    /// <summary>

    /// Converts the value.

    /// </summary>

    /// <typeparam name="U">The type to convert the value to.</typeparam>

    /// <param name="value">A <see cref="JToken"/> cast as a <see cref="IEnumerable{T}"/> of <see cref="JToken"/>.</param>

    /// <returns>A converted value.</returns>

    public static U Value<U>(this IEnumerable<JToken> value)

    {

      return value.Value<JToken, U>();

    }

    /// <summary>

    /// Converts the value.

    /// </summary>

    /// <typeparam name="T">The source collection type.</typeparam>

    /// <typeparam name="U">The type to convert the value to.</typeparam>

    /// <param name="value">A <see cref="JToken"/> cast as a <see cref="IEnumerable{T}"/> of <see cref="JToken"/>.</param>

    /// <returns>A converted value.</returns>

    public static U Value<T, U>(this IEnumerable<T> value) where T : JToken

    {

      ValidationUtils.ArgumentNotNull(value, "source");

      JToken token = value as JToken;

      if (token == null)

        throw new ArgumentException("Source value must be a JToken.");

      return token.Convert<JToken, U>();

    }

    internal static IEnumerable<U> Values<T, U>(this IEnumerable<T> source, object key) where T : JToken

    {

      ValidationUtils.ArgumentNotNull(source, "source");

      foreach (JToken token in source)

      {

        if (key == null)

        {

          if (token is JValue)

          {

            yield return Convert<JValue, U>((JValue)token);

          }

          else

          {

            foreach (JToken t in token.Children())

            {

              yield return t.Convert<JToken, U>(); ;

            }

          }

        }

        else

        {

          JToken value = token[key];

          if (value != null)

            yield return value.Convert<JToken, U>();

        }

      }

      yield break;

    }

    //TODO

    //public static IEnumerable<T> InDocumentOrder<T>(this IEnumerable<T> source) where T : JObject;

    //public static IEnumerable<JToken> Children<T>(this IEnumerable<T> source) where T : JToken

    //{

    //  ValidationUtils.ArgumentNotNull(source, "source");

    //  return source.SelectMany(c => c.Children());

    //}

    /// <summary>

    /// Returns a collection of child tokens of every array in the source collection.

    /// </summary>

    /// <typeparam name="T">The source collection type.</typeparam>

    /// <param name="source">An <see cref="IEnumerable{T}"/> of <see cref="JToken"/> that contains the source collection.</param>

    /// <returns>An <see cref="IEnumerable{T}"/> of <see cref="JToken"/> that contains the values of every node in the source collection.</returns>

    public static IJEnumerable<JToken> Children<T>(this IEnumerable<T> source) where T : JToken

    {

      return Children<T, JToken>(source).AsJEnumerable();

    }

    /// <summary>

    /// Returns a collection of converted child tokens of every array in the source collection.

    /// </summary>

    /// <param name="source">An <see cref="IEnumerable{T}"/> of <see cref="JToken"/> that contains the source collection.</param>

    /// <typeparam name="U">The type to convert the values to.</typeparam>

    /// <typeparam name="T">The source collection type.</typeparam>

    /// <returns>An <see cref="IEnumerable{T}"/> that contains the converted values of every node in the source collection.</returns>

    public static IEnumerable<U> Children<T, U>(this IEnumerable<T> source) where T : JToken

    {

      ValidationUtils.ArgumentNotNull(source, "source");

      return source.SelectMany(c => c.Children()).Convert<JToken, U>();

    }

    internal static IEnumerable<U> Convert<T, U>(this IEnumerable<T> source) where T : JToken

    {

      ValidationUtils.ArgumentNotNull(source, "source");

      bool cast = typeof(JToken).IsAssignableFrom(typeof(U));

      foreach (JToken token in source)

      {

        yield return Convert<JToken, U>(token, cast);

      }

    }

    internal static U Convert<T, U>(this T token) where T : JToken

    {

      bool cast = typeof(JToken).IsAssignableFrom(typeof(U));

      return Convert<T, U>(token, cast);

    }

    internal static U Convert<T, U>(this T token, bool cast) where T : JToken

    {

      if (cast)

      {

        // HACK

        return (U)(object)token;

      }

      else

      {

        if (token == null)

          return default(U);

        JValue value = token as JValue;

        if (value == null)

          throw new InvalidCastException("Cannot cast {0} to {1}.".FormatWith(CultureInfo.InvariantCulture, token.GetType(), typeof(T)));

        Type targetType = typeof(U);

        if (ReflectionUtils.IsNullableType(targetType))

        {

          if (value.Value == null)

            return default(U);

          targetType = Nullable.GetUnderlyingType(targetType);

        }

        return (U)System.Convert.ChangeType(value.Value, targetType, CultureInfo.InvariantCulture);

      }

    }

    //TODO

    //public static void Remove<T>(this IEnumerable<T> source) where T : JContainer;

    /// <summary>

    /// Returns the input typed as <see cref="IJEnumerable{T}"/>.

    /// </summary>

    /// <param name="source">An <see cref="IEnumerable{T}"/> of <see cref="JToken"/> that contains the source collection.</param>

    /// <returns>The input typed as <see cref="IJEnumerable{T}"/>.</returns>

    public static IJEnumerable<JToken> AsJEnumerable(this IEnumerable<JToken> source)

    {

      return source.AsJEnumerable<JToken>();

    }

    /// <summary>

    /// Returns the input typed as <see cref="IJEnumerable{T}"/>.

    /// </summary>

    /// <typeparam name="T">The source collection type.</typeparam>

    /// <param name="source">An <see cref="IEnumerable{T}"/> of <see cref="JToken"/> that contains the source collection.</param>

    /// <returns>The input typed as <see cref="IJEnumerable{T}"/>.</returns>

    public static IJEnumerable<T> AsJEnumerable<T>(this IEnumerable<T> source) where T : JToken

    {

      if (source == null)

        return null;

      else if (source is IJEnumerable<T>)

        return (IJEnumerable<T>)source;

      else

        return new JEnumerable<T>(source);

    }

  }

}