Iterating over Java collections in Scala

Question

I\'m writing some Scala code which uses the Apache POI API. I would like to iterate over the rows contained in the java.util.Iterator that I get from the Sheet

Answer 1

If you are iterating through a large dataset, then you probably don't want to load whole collection into memory with .asScala implicit conversion. In this case, a handy way approach is to implement scala.collection.Iterator trait

import java.util.{Iterator => JIterator}

def scalaIterator[T](it: JIterator[T]) = new Iterator[T] {
  override def hasNext = it.hasNext
  override def next() = it.next()
} 

val jIterator: Iterator[String] = ... // iterating over a large dataset
scalaIterator(jIterator).take(2).map(_.length).foreach(println)  // only first 2 elements are loaded to memory

It has similar concept but less verbose IMO :)