Parcelable helper to wrap object convertable with gson

ObjectGsonParceler.java

public class ObjectGsonParceler {
  private final Gson gson;

  public  ObjectGsonParceler(Gson gson) {
    this.gson = gson;
  }

  public Parcelable wrap(Object instance) {
    try {
      String json = encode(instance);
      return new Wrapper(json);
    } catch (IOException e) {
      throw new RuntimeException(e);
    }
  }

  public <T> T unwrap(Parcelable parcelable) {
    Wrapper wrapper = (Wrapper) parcelable;
    try {
      return decode(wrapper.json);
    } catch (IOException e) {
      throw new RuntimeException(e);
    }
  }

  private String encode(Object instance) throws IOException {
    StringWriter stringWriter = new StringWriter();
    JsonWriter writer = new JsonWriter(stringWriter);

    try {
      Class<?> type = instance.getClass();

      writer.beginObject();
      writer.name(type.getName());
      gson.toJson(instance, type, writer);
      writer.endObject();

      return stringWriter.toString();
    } finally {
      writer.close();
    }
  }

  private <T> T decode(String json) throws IOException {
    JsonReader reader = new JsonReader(new StringReader(json));

    try {
      reader.beginObject();

      Class<?> type = Class.forName(reader.nextName());
      return gson.fromJson(reader, type);
    } catch (ClassNotFoundException e) {
      throw new RuntimeException(e);
    } finally {
      reader.close();
    }
  }

  private static class Wrapper implements Parcelable {
    final String json;

    Wrapper(String json) {
      this.json = json;
    }

    @Override public int describeContents() {
      return 0;
    }

    @Override public void writeToParcel(Parcel out, int flags) {
      out.writeString(json);
    }

    public static final Creator<Wrapper> CREATOR = new Creator<Wrapper>() {
      @Override public Wrapper createFromParcel(Parcel in) {
        String json = in.readString();
        return new Wrapper(json);
      }

      @Override public Wrapper[] newArray(int size) {
        return new Wrapper[size];
      }
    };
  }
}