Support magical toJson(), fromJson() methods about moshi HOT 11 CLOSED

Shouldn't the returned object be String?

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This returns an object that can be converted to JSON, not a JSON object itself. Example:

class Point {
  double x;
  double y;

  public Object toJson() {
    return Arrays.asList(x, y);
  }
  public static Object fromJson(Object json) {
    List list = (List) json;
    return new Point((Double) list.get(0), (Double) list.get(1));
  }
}

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and what is the advantage of that over returning a String?

from moshi.

The advantage is in how the data looks in the finished JSON document. Imagine we have this:

  {
    "path": [[1,2],[3,4],[3,2],[1,4]]
  }

You could marshall this with this code, without registering any type adapters:

  class Shape {
    List<Point> path;
  }

from moshi.

even

class Shape {
    Point[] path;
}

?

from moshi.

Yup; that too.

from moshi.

I am dense, need more explanation. How is the same not achieved if toJson() returned a String instead.

from moshi.

toJson() is meant to customize JSON output to be different from the default representation based on the fields. I presume you meant that Shape class would not need to define toJson() because List and Point[] will automatically get serialized correctly. Well, that is no different from the default behavior based on fields.

from moshi.

Maybe the names could be a bit clearer? I don't have a good recommendation, though.

from moshi.

It’s in, and the final version looks a lot like @Provider methods.

  static class PointAsListOfIntegersJsonAdapter {
    @ToJson List<Integer> pointToJson(Point point) {
      return Arrays.asList(point.x, point.y);
    }

    @FromJson Point pointFromJson(List<Integer> o) throws Exception {
      if (o.size() != 2) throw new Exception("Expected 2 elements but was " + o);
      return new Point(o.get(0), o.get(1));
    }
  }

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@swankjesse Thanks for sharing the adapter snippet!

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