code: private void parseAttribute(final Attributes atts) {
          final URI attrValue = toURI(atts.getValue(ATTRIBUTE_NAME_HREF));
          if (attrValue == null) {
              return;
          }
  
          final String attrScope = atts.getValue(ATTRIBUTE_NAME_SCOPE);
          if (isExternal(attrValue, attrScope)) {
              return;
          }
  
          String attrFormat = atts.getValue(ATTRIBUTE_NAME_FORMAT);
          if (attrFormat == null || ATTR_FORMAT_VALUE_DITA.equals(attrFormat)) {
              final File target = toFile(attrValue);
              topicHref = target.isAbsolute() ? attrValue : currentDir.resolve(attrValue);
  
              if (attrValue.getFragment() != null) {
                  topicId = attrValue.getFragment();
              } else {
                  if (attrFormat == null || attrFormat.equals(ATTR_FORMAT_VALUE_DITA) || attrFormat.equals(ATTR_FORMAT_VALUE_DITAMAP)) {
                      topicId = topicHref + QUESTION;
                  }
              }
          } else {
              topicHref = null;
              topicId = null;
          }
      }
docs: Parse the href attribute for needed information.
  
  @param atts attributes to process