Known issues with Collection of Java classes

[zaleslaw]

[zaleslaw]

@belovrv could you share some details here and give some code snippets?

[zaleslaw]

@belovrv

[zaleslaw]

@belovrv

[belovrv]

Repro: I have a Java class like this:

public class Item {
    private final int val;
    public Item(int value) {
        val = value;
    }

    int getValue() {
        return val;
    }
}

And following Kotlin code:

class Item1(val value: Int)

data class Container(val item: Item, val item1: Item1)

fun main() {
    val arr = listOf(
        Container(Item(1), Item1(1)),
        Container(Item(2), Item1(3)),
        Container(Item(3), Item1(3))
        )
    println("${arr[0].item.value}, ${arr[0].item1.value}")

    println(arr.toDataFrame(maxDepth = 2).toString())

}

The output is

1, 1
   item       item1
 0  { } { value:1 }
 1  { } { value:3 }
 2  { } { value:3 }

But expected that java property will be traversed by toDataFrame as well.

[Jolanrensen]

Java class traversing could be possible by scanning functions starting with
"get" or "is" using reflection. This is similar to how the Java Bean encoder from Spark scans Java 'data' classes.

Not that difficult, but it requires some research. Might look into it because it does sound fun