Hash-based search

lazyhashsearch.scala

// Sample implementation of a Hash-based search 
// from a lazy sequence e.g. Streams in Scala
// @author Raymond Tay
// @date 5 April 2012

import collection.mutable._

object LazyHashSearch {

    private[LazyHashSearch] var map = Map.empty[Int, List[Int]]

    // Pass in the Stream's iterator so that the values
    // can be hashed into the data structure
    def load(iter: Iterator[Int]) : Unit = {

        // pull all values from the iterator and find the 
        // bin to hash it to

        while( iter.hasNext ) {
          val a : Int = iter.next
          // we're supposed to hash 'a' and bin it but since we're 
          // already at the 'bottom' of the types...well
          if (! map.contains(a) ) map = map + (a -> List(a))
          if (  map.contains(a) ) map + (a -> map.get(a).get.::(a) )
          // if (  map.contains(a) ) map + (a, (a :: map.get(a).get) )
        }
    }

    def search(v: Int) : Boolean = {
        if ( !map.contains(v) ) false
        true
    }

    def main(args: Array[String]) = {
        val iS = Stream.iterate(1, 10000){_ + 1} // generate a lazy list {1, 2, ... , 10000}
        load(iS.iterator)
        println( search(5555) ) 
    }
}