@Synchronized
  @Throws(IOException::class)
  override fun flush() {
    if (!initialized) return

    checkNotClosed()
    trimToSize()
    journalWriter!!.flush()
  }

  @Synchronized fun isClosed(): Boolean = closed

  /** Closes this cache. Stored values will remain on the filesystem. */
  @Synchronized
  @Throws(IOException::class)
  override fun close() {
    if (!initialized || closed) {