gson-flatten

Additional

Language
Java
Version
0.7 (Jun 29, 2017)
Created
May 19, 2016
Updated
Jun 30, 2017
Owner
Tishka17
Contributors
tominsam
Tishka17
2
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gson-flatten

Library to collapse inner objects when parsing json

  1. To use library you should add it in your build.gradle:

        compile 'org.itishka.gson-flatten:gson-flatten:0.7'
  2. Then register it in your gson builder:

    final Gson gson = new GsonBuilder()
              .registerTypeAdapterFactory(new FlattenTypeAdapterFactory())
              .create();
  3. Define your class and use @Flatten annotation to get data from embedded objects. For example class

    class Weather {
      @Flatten("temperature::min")
      int min_temperture;
      @Flatten("temperature::max")
      int max_temperture;
    }

    will be filled with data from json

    {
      "temperature": {
         "min": -273,
         "max": 1000
      }
    }
  4. Then just parse or serialize json as your usually do:

      String json = gson.toJson(weather);
      Weather weather2 = gson.fromJson(json, Weather.class);

Additional features

  • You can skip field name if it equlas in inner object and outer one. E.g.:
class Weather {
    @Flatten("temperature::")
    int min;
    @Flatten("temperature::")
    int max;
}
  • You can get array items as well (tnx @tominsam):
class SomeClass {
    @Flatten("some_array::0")
    int first_value;
}
  • If you are using Gson 2.7 with some FieldNamingStrategies with and gson-flatten 0.6 you do not need to do anything more!

With previous versions of gson and gson-flatten you should provide FieldNamingStrategy to FlattenTypeAdapterFactory:

final Gson gson = new GsonBuilder()
          .setFieldNamingPolicy(FieldNamingPolicy.UPPER_CAMEL_CASE)
          .registerTypeAdapterFactory(new FlattenTypeAdapterFactory(FieldNamingPolicy.UPPER_CAMEL_CASE))
          .create();

License

Based on https://github.com/noties/Flatten

Gson-flatten is released under LGPL 3.0 license