UDF prototype for array parameter

[Sergey Bartunov]

Hello. I'm trying to write my own UDF in Scala which takes two
parameters of array<double> type and returns double. I used the next
prototype:

public DoubleWritable evaluate(ArrayWritable x, ArrayWritable y);

I've successfully registered all necessary jars and created temporary
function for my UDF.

And then..

hive> describe test;
OK
id      int     
oksa    array<double>
hive> select myudf(oksa, oksa) from test;
FAILED: Unknown exception : Cannot get UDF for myudf [array<double>,
array<double>]

So what parameter type I have to use for array<double>?

Here is the full source:

package com.buerak.test;

import org.apache.hadoop.hive.ql.exec.UDF;
import scala.collection.JavaConversions._;
import org.apache.hadoop.io.DoubleWritable;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.Writable;
import org.apache.hadoop.io.ArrayWritable;

class AlwaysThree extends UDF {
        def evaluate(x: ArrayWritable, y: ArrayWritable): DoubleWritable =
        {
            new DoubleWritable(3)
        }
}