public void write(int c) throws IOException {
    checkNotClosed();
    target.append((char) c);
  }

  @Override
  public void write(String str) throws IOException {
    checkNotNull(str);
    checkNotClosed();
    target.append(str);
  }

  @Override
  public void write(String str, int off, int len) throws IOException {
    checkNotNull(str);
    checkNotClosed();
    // tricky: append takes start, end pair...

    }

    return true
  }

  @Synchronized private fun checkNotClosed() {
    check(!closed) { "cache is closed" }
  }

  /** Force buffered operations to the filesystem. */
  @Synchronized
  @Throws(IOException::class)
  override fun flush() {
    if (!initialized) return

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