Simple scala class for automatically reloading properties from file

PropsLoader.scala

class PropsLoader(val filePath:String, val defaults:Map[String, String] = Map(), val reloadSecs:Int = 5) {
  import java.util.concurrent.atomic._
  
  private val file = new java.io.File(filePath)
  if (!file.isFile) throw new IllegalArgumentException(s"'$filePath' at ${file.getAbsolutePath} is not a file")
  
  private var javaProps = new java.util.Properties
  @volatile //synchronizes, could add thread-local cache
  private var props = defaults
  private val lastLoadCheck = new AtomicLong(-1)
  private val fileLastModified = new AtomicLong(-1)
  
  def sync = {
    val now = System.currentTimeMillis
    if ((now - lastLoadCheck.getAndSet(now))/1000 >= reloadSecs) {
      val lm = file.lastModified
      if (lm > fileLastModified.getAndSet(lm)) {
        val fr = new java.io.FileReader(file)
        javaProps.load(fr)
        fr.close
        props = defaults ++ javaProps
      }
    }
  }
  def get = { sync; props }
  sync
}