CODEWITHSUNDEEP
scalaapache-sparkcassandraspark-cassandra-connector
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Reputation: 2517

Spark: GenericMutableRow cannot be cast to java.lang.Byte and <none> is not a term

I am trying to store data from a Spark (v.1.6) DataFrame to Cassandra. I managed to get the examples on the Spark Cassandra Connector page running, however, I am stuck with my own code. Consider the following snippet:

case class MyCassandraRow(id : Long, sfl : Seq[Float])

df.map(r => 
   MyCassandraRow(
        r.getAsLong(0),
        r.getAs[MySeqFloatWrapper]("sfl").getSeq())
).saveToCassandra("keyspace", "table")

MySeqFloatWrapper is a UDT, I wrote, which has a method getSeq() and returns a Seq[Float].

Unfortunately, if I run this code, I get a 

java.lang.ClassCastException: org.apache.spark.sql.catalyst.expressions.GenericMutableRow cannot be cast to java.lang.Byte

Actually, I get this exception even if I do (and also if I do Row(r.getLong(0))), but not if I write:

df.map(r => r.getLong(0)).collect()

On the other hand, if I add a Row around my case class and I write

df.map(r => 
  Row(
   MyCassandraRow(
        r.getAsLong(0),
        r.getAs[MySeqFloatWrapper]("sfl").getSeq())
  )
).saveToCassandra("keyspace", "table")

I get the following exception:

scala.ScalaReflectionException: <none> is not a term

Upvotes: 2

Views: 697

Answers (1)

navige
navige

Reputation: 2517

I just realized that the ClassCastException was related to my UDT MySeqFloatWrapper and the sqlType I defined there, which apparently was not considered so far as with Spark 1.5 it worked fine, but with Spark 1.6 no longer (see also SPARK-12878).

If you need a template to see how to define UDTs properly, see also the VectorUDT example on github.

Upvotes: 3

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