public Object getAttribute(File file, String view, String attribute) {
    Object value = getAttributeInternal(file, view, attribute);
    if (value == null) {
      throw new IllegalArgumentException("invalid attribute for view '" + view + "': " + attribute);
    }
    return value;
  }
Gets the value of the given attribute for the given view and file. Neither view nor attribute
may have a ':' character.
jimfs/src/main/java/com/google/common/jimfs/AttributeService.java