File: StringEnumConverter.cs

package info (click to toggle)
mono 4.6.2.7+dfsg-1
  • links: PTS, VCS
  • area: main
  • in suites: stretch
  • size: 778,148 kB
  • ctags: 914,052
  • sloc: cs: 5,779,509; xml: 2,773,713; ansic: 432,645; sh: 14,749; makefile: 12,361; perl: 2,488; python: 1,434; cpp: 849; asm: 531; sql: 95; sed: 16; php: 1
file content (201 lines) | stat: -rw-r--r-- 7,111 bytes parent folder | download | duplicates (2)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
#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.Globalization;
using System.Reflection;
using System.Runtime.Serialization;
using Newtonsoft.Json.Utilities;
#if NET20
using Newtonsoft.Json.Utilities.LinqBridge;
#else
using System.Linq;
#endif

namespace Newtonsoft.Json.Converters
{
  /// <summary>
  /// Converts an <see cref="Enum"/> to and from its name string value.
  /// </summary>
  /// <summary>
  /// Converts an <see cref="Enum"/> to and from its name string value.
  /// </summary>
  public class StringEnumConverter : JsonConverter
  {
    private readonly Dictionary<Type, BidirectionalDictionary<string, string>> _enumMemberNamesPerType = new Dictionary<Type, BidirectionalDictionary<string, string>>();

    /// <summary>
    /// Gets or sets a value indicating whether the written enum text should be camel case.
    /// </summary>
    /// <value><c>true</c> if the written enum text will be camel case; otherwise, <c>false</c>.</value>
    public bool CamelCaseText { get; set; }
    
    /// <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)
    {
      if (value == null)
      {
        writer.WriteNull();
        return;
      }

      Enum e = (Enum)value;

      string enumName = e.ToString("G");

      if (char.IsNumber(enumName[0]) || enumName[0] == '-')
      {
        writer.WriteValue(value);
      }
      else
      {
        BidirectionalDictionary<string, string> map = GetEnumNameMap(e.GetType());

        string resolvedEnumName;
        map.TryGetByFirst(enumName, out resolvedEnumName);
        resolvedEnumName = resolvedEnumName ?? enumName;

        if (CamelCaseText)
        {
          string[] names = resolvedEnumName.Split(',').Select(item => StringUtils.ToCamelCase(item.Trim())).ToArray();
          resolvedEnumName = string.Join(", ", names);
        }

        writer.WriteValue(resolvedEnumName);
      }
    }

    /// <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)
    {
      Type t = (ReflectionUtils.IsNullableType(objectType))
      ? Nullable.GetUnderlyingType(objectType)
      : objectType;

      if (reader.TokenType == JsonToken.Null)
      {
        if (!ReflectionUtils.IsNullableType(objectType))
          throw new Exception("Cannot convert null value to {0}.".FormatWith(CultureInfo.InvariantCulture, objectType));

        return null;
      }

      if (reader.TokenType == JsonToken.String)
      {
        var map = GetEnumNameMap(t);
        string resolvedEnumName;
        map.TryGetBySecond(reader.Value.ToString(), out resolvedEnumName);
        resolvedEnumName = resolvedEnumName ?? reader.Value.ToString();

        return Enum.Parse(t, resolvedEnumName, true);
      }

      if (reader.TokenType == JsonToken.Integer)
        return ConvertUtils.ConvertOrCast(reader.Value, CultureInfo.InvariantCulture, t);

      throw new Exception("Unexpected token when parsing enum. Expected String or Integer, got {0}.".FormatWith(CultureInfo.InvariantCulture, reader.TokenType));
    }

    /// <summary>
    /// A cached representation of the Enum string representation to respect per Enum field name.
    /// </summary>
    /// <param name="t">The type of the Enum.</param>
    /// <returns>A map of enum field name to either the field name, or the configured enum member name (<see cref="EnumMemberAttribute"/>).</returns>
    private BidirectionalDictionary<string, string> GetEnumNameMap(Type t)
    {
      BidirectionalDictionary<string, string> map;

      if (!_enumMemberNamesPerType.TryGetValue(t, out map))
      {
        lock (_enumMemberNamesPerType)
        {
          if (_enumMemberNamesPerType.TryGetValue(t, out map))
            return map;

          map = new BidirectionalDictionary<string, string>(
            StringComparer.OrdinalIgnoreCase,
            StringComparer.OrdinalIgnoreCase);

          foreach (FieldInfo f in t.GetFields())
          {
            string n1 = f.Name;
            string n2;
            
#if !NET20
            n2 = f.GetCustomAttributes(typeof (EnumMemberAttribute), true)
                          .Cast<EnumMemberAttribute>()
                          .Select(a => a.Value)
                          .SingleOrDefault() ?? f.Name;
#else
            n2 = f.Name;
#endif

            string s;
            if (map.TryGetBySecond(n2, out s))
            {
              throw new Exception("Enum name '{0}' already exists on enum '{1}'."
                .FormatWith(CultureInfo.InvariantCulture, n2, t.Name));
            }

            map.Add(n1, n2);
          }

          _enumMemberNamesPerType[t] = map;
        }
      }

      return map;
    }

    /// <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)
    {
      Type t = (ReflectionUtils.IsNullableType(objectType))
      ? Nullable.GetUnderlyingType(objectType)
      : objectType;

      return t.IsEnum();
    }
  }
}