code: public TagFileInfo getTagFile(String shortname) {
          TagFileInfo tagFiles[] = getTagFiles();
  
          if (tagFiles == null || tagFiles.length == 0) {
              return null;
          }
  
          for (int i=0; i < tagFiles.length; i++) {
              if (tagFiles[i].getName().equals(shortname)) {
                  return tagFiles[i];
              }
          }
          return null;
      }
docs: Get the TagFileInfo for a given tag name, looking through all the
  tag files in this tag library.
  
  @param shortname The short name (no prefix) of the tag
  @return the TagFileInfo for the specified Tag file, or null
  if no Tag file is found
  @since JSP 2.0