public static LinkedHashMap<String, Set<String>> extractJiraIssuesByVersion(
      Repository repository, List<String> versionTagList, String pattern)
      throws IOException, GitAPIException {

    LinkedHashMap<String, Set<String>> linkedHashMap = new LinkedHashMap<String, Set<String>>();

    int lenght = versionTagList.size();
    for (int i = 0; i < lenght; i++) {
      String sinceTagName = versionTagList.get(i);
      String untilTagName = i + 1 > lenght - 1 ? null : versionTagList.get(i + 1);
      linkedHashMap.put(
          versionTagList.get(i),
          extractJiraIssues(repository, sinceTagName, untilTagName, pattern));
    }
    return linkedHashMap;
  }
 @Override
 protected IStatus performJob() {
   try {
     // list all tags
     File gitDir = GitUtils.getGitDir(path);
     Repository db = new FileRepository(gitDir);
     Git git = new Git(db);
     List<Ref> refs = git.tagList().call();
     JSONObject result = new JSONObject();
     List<Tag> tags = new ArrayList<Tag>();
     for (Ref ref : refs) {
       Tag tag = new Tag(cloneLocation, db, ref);
       tags.add(tag);
     }
     Collections.sort(tags, Tag.COMPARATOR);
     JSONArray children = new JSONArray();
     int firstTag = pageSize > 0 ? pageSize * (pageNo - 1) : 0;
     int lastTag = pageSize > 0 ? firstTag + pageSize - 1 : tags.size() - 1;
     lastTag = lastTag > tags.size() - 1 ? tags.size() - 1 : lastTag;
     if (pageNo > 1 && baseLocation != null) {
       String prev = baseLocation + "?page=" + (pageNo - 1) + "&pageSize=" + pageSize;
       if (commitsSize > 0) {
         prev += "&" + GitConstants.KEY_TAG_COMMITS + "=" + commitsSize;
       }
       result.put(ProtocolConstants.KEY_PREVIOUS_LOCATION, prev);
     }
     if (lastTag < tags.size() - 1) {
       String next = baseLocation + "?page=" + (pageNo + 1) + "&pageSize=" + pageSize;
       if (commitsSize > 0) {
         next += "&" + GitConstants.KEY_TAG_COMMITS + "=" + commitsSize;
       }
       result.put(ProtocolConstants.KEY_NEXT_LOCATION, next);
     }
     for (int i = firstTag; i <= lastTag; i++) {
       Tag tag = tags.get(i);
       if (this.commitsSize == 0) {
         children.put(tag.toJSON());
       } else {
         // add info about commits if requested
         LogCommand lc = git.log();
         String toCommitName = tag.getRevCommitName();
         ObjectId toCommitId = db.resolve(toCommitName);
         Ref toCommitRef = db.getRef(toCommitName);
         toCommitId = getCommitObjectId(db, toCommitId);
         lc.add(toCommitId);
         lc.setMaxCount(this.commitsSize);
         Iterable<RevCommit> commits = lc.call();
         Log log = new Log(cloneLocation, db, commits, null, null, toCommitRef);
         children.put(tag.toJSON(log.toJSON(1, commitsSize)));
       }
     }
     result.put(ProtocolConstants.KEY_CHILDREN, children);
     result.put(ProtocolConstants.KEY_TYPE, Tag.TYPE);
     return new ServerStatus(Status.OK_STATUS, HttpServletResponse.SC_OK, result);
   } catch (Exception e) {
     String msg = NLS.bind("An error occured when listing tags for {0}", path);
     return new Status(IStatus.ERROR, GitActivator.PI_GIT, msg, e);
   }
 }