CODEWITHSUNDEEP
scalaarraylistiterator
Kalpesh
Kalpesh

Reputation: 704

convert scala.collection.Iterator to java list

Is there any direct API to convert scala.collection.Iterator to java list.

I tried following things:

val xs = Iterator[POJO]
println("xs size : " + xs.size)
import com.google.common.collect.Lists;
val p = Lists.newArrayList(xs)
**output** :
xs size : 1
p : [empty iterator]

case 2:

val input:Iterator[POJO] = xs.asJava
val m = ImmutableList.copyOf(input)
println("m value : " + m.toString())
**output**:
xs size : 1
m value : []

case 3:

val n = xs.toList.asJava;
println("n value : " + n.toString())
**output**
n value : []

Upvotes: 0

Views: 1293

Answers (1)

tkachuko
tkachuko

Reputation: 1986

Iterator can be consumed exactly once and I can see that you try to reuse the same iterator for the case 3 even though conversion itself is correct.

Below you can find simple function that converts scala iterator to java list using approach in case 3:

  def iteratorToJavaList[T](iterator: Iterator[T]): java.util.List[T] = {
    import collection.JavaConverters._
    iterator.toList.asJava
  }

and it can be used like this:

val scalaIterator = List(1, 2, 3).iterator
println(iteratorToJavaList(scalaIterator))

which results:

[1, 2, 3]

Upvotes: 4

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