Getting OWLEntity label in Scala

GetLabelExample.scala

package org.nescent.informatics.script

import org.semanticweb.owlapi.model.OWLEntity
import org.semanticweb.owlapi.model.OWLOntology
import scala.collection.JavaConversions._
import org.semanticweb.owlapi.model.OWLLiteral
import org.semanticweb.owlapi.model.OWLDataFactory
import org.semanticweb.owlapi.apibinding.OWLManager

object GetLabelExample {

  val ont: OWLOntology = null
  val factory: OWLDataFactory = OWLManager.getOWLDataFactory

  class MultiLabelException(obj: OWLEntity) extends Exception

  def getLabel(obj: OWLEntity): Option[String] = {
    val labels = obj.getAnnotations(ont, factory.getRDFSLabel).map(_.getValue).collect(
      { case literal: OWLLiteral => literal.getLiteral.toString })
    if (labels.size > 1) throw new MultiLabelException(obj)
    else labels.headOption
  }

}