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abstract class AbsIterator {
type T
def hasNext: Boolean
def next: T
}
trait RichIterator extends AbsIterator {
def foreach(f: T => Unit) {
while (hasNext) f(next)
}
}
class StringIterator(s: String) extends AbsIterator {
type T = Char
private var i = 0
def hasNext = i < s.length()
def next = { val x = s.charAt(i); i += 1; println("next: " + x); x }
}
trait SyncIterator extends AbsIterator {
abstract override def hasNext: Boolean =
synchronized(super.hasNext)
abstract override def next: T =
synchronized {
println("<sync>"); val x = super.next; println("</sync>"); x
}
}
trait LoggedIterator extends AbsIterator {
abstract override def next: T = {
val x = super.next; println("log: " + x); x
}
}
class Iter2(s: String) extends StringIterator(s)
with SyncIterator with LoggedIterator;
object Test {
def main(args: Array[String]) {
class Iter extends StringIterator(args(0)) with RichIterator with SyncIterator with LoggedIterator
val iter = new Iter
iter foreach Console.println
}
}
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