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 class. I would like to use the iterator in a for each
style loop, so I have been trying to convert it to a native Scala collection but will no luck.
I have looked at the Scala wrapper classes/traits, but I can not see how to use them correctly. How do I iterate over a Java collection in Scala without using the verbose while(hasNext()) getNext()
style of loop?
Here's the code I wrote based on the correct answer:
class IteratorWrapper[A](iter:java.util.Iterator[A])
{
def foreach(f: A => Unit): Unit = {
while(iter.hasNext){
f(iter.next)
}
}
}
object SpreadsheetParser extends Application
{
implicit def iteratorToWrapper[T](iter:java.util.Iterator[T]):IteratorWrapper[T] = new IteratorWrapper[T](iter)
override def main(args:Array[String]):Unit =
{
val ios = new FileInputStream("assets/data.xls")
val workbook = new HSSFWorkbook(ios)
var sheet = workbook.getSheetAt(0)
var rows = sheet.rowIterator()
for (val row <- rows){
println(row)
}
}
}
As of Scala 2.8, all you have to do is to import the JavaConversions object, which already declares the appropriate conversions.
import scala.collection.JavaConversions._
This won't work in previous versions though.