Moshi incorrectly deserializes an integer into a double-value

[sqrt-1764]

I am deserializing a map with name/value pairs where the values can have any value-type. So no class with members of a defined type can be given to deserialize into.

I can deserialize into a Map<String,Object> (the only solution), but then all numbers are deserialized into doubles. The underlying problem is that integers are wrongly convertet to doubles.

A simple call to

moshi.adapter(Object.class).fromJson("1234")

demonstrates this. Here a double is returned, whereas the argument describes an integer.

[JakeWharton]

JSON only has numbers. Not integers or doubles. And since numbers can have decimals they are always represented as doubles in Java.

[swankjesse]

Yep! And if you really want, you can get a Map<String, Integer> like so:

JsonAdapter<Map<String, Integer>> adapter
    = moshi.adapter(Types.newParameterizedType(Map.class, String.class, Integer.class);
adapter.fromJson("{\"a\": 1234}")

[sqrt-1764]

The pure JSON does not distinguish between integers and doubles, correct. But I see a subtle difference in the notation that can be used to separate integers from doubles. And converting from Java to JSON with moshi this is currently already implemented:

              Java -> Json

double: 1234.567 -> 1234.567
double: 1234.0 -> 1234.0
long: 1234 -> 1234

So an integer can be identified by a missing decimal point. Otherwise the 2nd and 3rd line would have to be converted the same.

So the conversion back would be: If it is a number and there is no decimal point convert to long otherwise to double.

The problem that I try to solve is to synchronize abitrary datatables between systems with JSON. So I know that the names of the fields are strings, but I know nothing about the types of the fields. And as integers can not always be correctly mapped to doubles I have to distinguish between those types.

At the moment I don't know how to write an adapter that returns more than one type. So I would have to use Object as return type. But what would be the input type? (I refer to the examples in the documentation with the @FromJSON annotations)
The solution from @swankjesse does not solve the problem as I can not tell which field has which type.

[swankjesse]

You can read numbers in Moshi as strings and decode to your preferred format using your preferred rules.

[sqrt-1764]

Maybe I did not get your point.
I can not map the numbers to strings because I would lose the difference between numbers and strings then.
So how to intercept the parser before he converts the numbers and return the appropriate type from there? Currently I do not see how to accomplish this with JsonAdapters.
I opened a question in StackOverflow for this: [http://stackoverflow.com/questions/39658090/how-to-distinguish-long-and-double-values-when-deserializing-with-moshi]

[fmachado]

I've a scenario where I cannot enforce a type so, things like

JsonAdapter<Map<String, Integer>> adapter = ...

are not a viable option.

Would be possible to handle non-floating point numbers as int, long or BigInteger as Jackson does?

[NightlyNexus]

In Moshi 1.6.0, you will be able to do this.

https://github.com/square/moshi/pull/316/files#diff-377a789dd290133f2491a9d6b5d3bad8R221