NavMapSeq

The NavMapSeq actor is a wrapper around a NavigableMap.

class NavMapSeq[K, V](navigableMap: NavigableMap[K, V])
  extends Sequence[K, V](mailbox, factory) {

  override def first(msg: AnyRef, rf: Any => Unit) {
    if (navigableMap.isEmpty) rf(null)
    else {
      val entry = navigableMap.firstEntry
      rf(KVPair(entry.getKey, entry.getValue))
    }
  }

  override def current(msg: AnyRef, rf: Any => Unit) {
    if (navigableMap.isEmpty) rf(null)
    else {
      var key = msg.asInstanceOf[Current[K]].key
      val entry = navigableMap.ceilingEntry(key)
      if (entry == null) rf(null)
      else rf(KVPair(entry.getKey, entry.getValue))
    }
  }

  override def next(msg: AnyRef, rf: Any => Unit) {
    if (navigableMap.isEmpty) rf(null)
    else {
      var key = msg.asInstanceOf[Next[K]].key
      val entry = navigableMap.higherEntry(key)
      if (entry == null) rf(null)
      else rf(KVPair(entry.getKey, entry.getValue))
    }
  }

  override protected def _comparator: Comparator[_ >: K] = {
    val c = navigableMap.comparator
    if (c != null) c
    else super._comparator
  }
}

Test code.

val alphabet = new java.util.TreeMap[String, String]
alphabet.put("a", "Apple")
alphabet.put("b", "Boy")
alphabet.put("c", "Cat")
val alphabetSeq = new NavMapSeq(alphabet)
println(Future(alphabetSeq, First()))
println(Future(alphabetSeq, Current("")))
println(Future(alphabetSeq, Next("a")))
println(Future(alphabetSeq, Current("d")))
println(Future(alphabetSeq, Next("aa")))

Output.

KVPair(a,Apple)
KVPair(a,Apple)
KVPair(b,Boy)
null
KVPair(b,Boy)

NavMapTest

Tutorial