LowerCaseEnumTypeAdapterFactory.java

package net.minecraft.launcher.updater;

import com.google.gson.Gson;
import com.google.gson.TypeAdapter;
import com.google.gson.TypeAdapterFactory;
import com.google.gson.reflect.TypeToken;
import com.google.gson.stream.JsonReader;
import com.google.gson.stream.JsonToken;
import com.google.gson.stream.JsonWriter;
import java.io.IOException;
import java.util.HashMap;
import java.util.Locale;
import java.util.Map;

public class LowerCaseEnumTypeAdapterFactory
  implements TypeAdapterFactory
{
  public <T> TypeAdapter<T> create(Gson gson, TypeToken<T> type)
  {
    Class rawType = type.getRawType();
    if (!rawType.isEnum()) {
      return null;
    }

    final Map lowercaseToConstant = new HashMap();
    for (Object constant : rawType.getEnumConstants()) {
      lowercaseToConstant.put(toLowercase(constant), constant);
    }

    return new TypeAdapter() {
      public void write(JsonWriter out, T value) throws IOException {
        if (value == null)
          out.nullValue();
        else
          out.value(LowerCaseEnumTypeAdapterFactory.this.toLowercase(value));
      }

      public T read(JsonReader reader) throws IOException
      {
        if (reader.peek() == JsonToken.NULL) {
          reader.nextNull();
          return null;
        }
        return lowercaseToConstant.get(reader.nextString());
      }
    };
  }

  private String toLowercase(Object o)
  {
    return o.toString().toLowerCase(Locale.US);
  }
}