http://groups.google.com/group/scala-user/browse_thread/thread/4a71e3948419ea91

k.scala

// -*- mode: Scala;-*- 
// Filename:    k.scala 
// Authors:     lgm                                                    
// Creation:    Wed Dec 28 14:52:27 2011 
// Copyright:   Not supplied 
// Description: 
// ------------------------------------------------------------------------

import scala.collection.mutable.HashMap
import scala.util.continuations._
import com.thoughtworks.xstream.XStream
import com.thoughtworks.xstream.io.json.JettisonMappedXmlDriver

import biz.source_code.base64Coder.Base64Coder
//import java.util._
import java.io.ObjectInputStream
import java.io.ByteArrayInputStream
import java.io.ObjectOutputStream
import java.io.ByteArrayOutputStream

/** 
 * Usage sample serializing SomeClass instance 
 */
object ObjectToString {  
  /** Read the object from Base64 string. */
  def fromString( s : String ) : java.lang.Object = {
    val data : Array[Byte] = Base64Coder.decode( s )
    val ois : ObjectInputStream =
      new ObjectInputStream( new ByteArrayInputStream(  data ) )
    val o : java.lang.Object = ois.readObject();
    ois.close()
    o
  }

  /** Write the object to a Base64 string. */
  def toString( o : Serializable ) : String = {
    val baos : ByteArrayOutputStream = new ByteArrayOutputStream()
    val oos : ObjectOutputStream = new ObjectOutputStream( baos )
    oos.writeObject( o )
    oos.close()
    new String( Base64Coder.encode( baos.toByteArray() ) )
  }
}

object OK {
  def coral( useXStream : Boolean )(
    kmap : HashMap[String, (String => Unit)],
    ksmap : HashMap[String,String],
    key : String
  ) = {
    reset {
      shift {
	( k : ( String => Unit ) ) => {
	  val ks =
	    if ( useXStream ) {
	      new XStream( new JettisonMappedXmlDriver() ).toXML( k )
	    }
	    else {
	      ObjectToString.toString( k.asInstanceOf[Serializable] )
	    }
	  println( "continuation as string: " + ks )
	  ksmap += ( ( key, ks ) )
	  kmap += ( ( key, k ) )
	  k( ks )
	}
      }
      println( "resuming..." )
      println( "searching kmap : " + kmap )
      println( "kmap id : " + System.identityHashCode(kmap)) // add this line
     for(
	fns <- kmap.get( key )
      ) {
	println( "fns is " + fns );
      }
    }
  }
}

output.txt

scala> :l k.scala
Loading k.scala...
import scala.collection.mutable.HashMap
import scala.util.continuations._
import biz.source_code.base64Coder.Base64Coder
import java.io.ObjectInputStream
import java.io.ByteArrayInputStream
import java.io.ObjectOutputStream
import java.io.ByteArrayOutputStream
defined module ObjectToString
defined module OK

scala> val ksmap1 = new HashMap[String,String]( ) 
ksmap1: scala.collection.mutable.HashMap[String,String] = Map()

scala> val kmap1 = new HashMap[String,(String => Unit)]( ) 
kmap1: scala.collection.mutable.HashMap[String,String => Unit] = Map()

scala> OK.coral( false )( kmap1, ksmap1, "Erp" ) 
continuation as string: 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
resuming...
searching kmap : Map(Erp -> <function1>)
kmap id : 24530783
fns is <function1>

scala> kmap1( "Erp" )( "Erp" ) 
resuming...
searching kmap : Map(Erp -> <function1>)
kmap id : 24530783
fns is <function1>

scala> val rK1 = ObjectToString.fromString( ksmap1( "Erp" ) 
     | ).asInstanceOf[( String => Unit )] 
rK1: String => Unit = <function1>

scala> rK1( "Erp" ) 
resuming...
searching kmap : Map()
kmap id : 4430367