code: public TagInfo getTag(String shortname) {
          TagInfo tags[] = getTags();
  
          if (tags == null || tags.length == 0) {
              return null;
          }
  
          for (int i=0; i < tags.length; i++) {
              if (tags[i].getTagName().equals(shortname)) {
                  return tags[i];
              }
          }
          return null;
      }
docs: Get the TagInfo for a given tag name, looking through all the
  tags in this tag library.
  
  @param shortname The short name (no prefix) of the tag
  @return the TagInfo for the tag with the specified short name, or
  null if no such tag is found