BramYeh

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

       final Map<String, T> lowercaseToConstant = new HashMap<String, T>();
       for (T constant : rawType.getEnumConstants()) {
         lowercaseToConstant.put(toLowercase(constant), constant);