How to retrieve value from a org.bytedeco.arrow.Scalar?

[xuchen-plus]

After calling an arrow::compute::ScalarAggregationFunction, it returns a Datum object which contains a Scalar object. However, there's no value() method in the generated java wrapper to retrieve the underlying value, e.g. long/int, etc.

My code:

ArrowBuf buf; // this is an int64 ArrowBuf java object initialized in java

// Below are all javacpp calls

ArrowBuffer buffer = new ArrowBuffer(buf.nioBuffer(), capacity);
ExecContext context = new ExecContext();
DataType type = int64();
PrimitiveArray array = new PrimitiveArray(type, capacity, buffer);
Function func = context.func_registry().GetFunction("sum").ValueOrDie();
DatumVector vector = new DatumVector(new Datum(array));
Scalar s = func.Execute(vector, null, context).ValueOrDie().scalar();
// How can I retrieve the `long` value from the Scalar result object here?  Haven't found such methods from either Scalar or Int64Scalar classes.

Please help advice. Thanks very much.

[saudet]

get() should work for most use cases... Let me know if that's not enough though.

[saudet]

Ah, sorry about that, I was confusing this with OpenCV. So, it looks like we need to use the internal API to access the data. Something like this should work:

long value = new LongPointer(new PrimitiveScalarBase(s).data()).get();

[xuchen-plus]

Ah, sorry about that, I was confusing this with OpenCV. So, it looks like we need to use the internal API to access the data. Something like this should work:

long value = new LongPointer(new PrimitiveScalarBase(s).data()).get();

Thanks, this works. And thank you for creating this great project!