private static PathMatcher fromRegex(String regex, Iterable<PathNormalization> normalizations) {
    return new RegexPathMatcher(PathNormalization.compilePattern(regex, normalizations));
  }
Gets a {@link PathMatcher} for the given syntax and pattern as specified by {@link
FileSystem#getPathMatcher}. The {@code separators} string contains the path name element
separators (one character each) recognized by the file system. For a glob-syntax path matcher,
any of the given separators will be recognized as a separator in the pattern, and any of them
will be matched as a separator when checking a path.
jimfs/src/main/java/com/google/common/jimfs/PathMatchers.java