code: @Override
    @NullSafe
    public boolean accept(File pathname) {
      return (pathname != null && pathname.isHidden() == hidden);
    }
docs: Determines whether the given {@link File} is accepted by this {@link FileFilter}, which evaluates whether
  the {@link File} is hidden or not.
  
  @param pathname the {@link File} to evaluate.
  @return a boolean value indicating whether hidden {@link File}s are accepted or rejected.
  @see org.cp.elements.lang.Filter#accept(Object)
  @see java.io.FileFilter#accept(File)
  @see java.io.File#isHidden()