private com.skt.opensocial.persistence.Activity setActivityDBFromActivity(
      Person user, String appId, Activity activity) {
    com.skt.opensocial.persistence.Activity activityDB =
        new com.skt.opensocial.persistence.Activity();

    activityDB.setAppId(appId);

    activityDB.setBody(activity.getBody());
    activityDB.setBodyId(activity.getBodyId());
    activityDB.setExternalId(activity.getExternalId());

    if (activity.getPriority() != null) activityDB.setPriority(new Double(activity.getPriority()));
    else activityDB.setPriority(new Double(0));

    activityDB.setStreamFaviconUrl(activity.getStreamFaviconUrl());
    activityDB.setStreamSourceUrl(activity.getStreamSourceUrl());
    activityDB.setStreamTitle(activity.getStreamTitle());
    activityDB.setStreamUrl(activity.getStreamUrl());
    activityDB.setTitle(activity.getTitle());

    // there should one of Title or TitleId
    if (activityDB.getTitle() == null) activityDB.setTitleId(activity.getTitleId());

    activityDB.setUpdated(activity.getUpdated());
    activityDB.setUrl(activity.getUrl());
    activityDB.setPerson(user);

    return activityDB;
  }
  public Future<Void> createActivity(
      UserId userId,
      GroupId groupId,
      String appId,
      Set<String> fields,
      Activity activity,
      SecurityToken token)
      throws ProtocolException {

    Session hs = HibernateUtil.getSessionFactory().getCurrentSession();
    Transaction tran = null;

    try {
      Long startTime = new Date().getTime();

      tran = hs.beginTransaction();

      // check if the person exists
      String user = userId.getUserId(token);
      Person person = (Person) hs.get(Person.class, user);

      if (person == null)
        throw new ProtocolException(HttpServletResponse.SC_BAD_REQUEST, "Person does not exist");

      if (activity.getStreamFaviconUrl() != null
          || activity.getStreamSourceUrl() != null
          || activity.getStreamTitle() != null
          || activity.getStreamUrl() != null)
        throw new ProtocolException(
            HttpServletResponse.SC_BAD_REQUEST, "Creating activity with stream params");

      // create Activity
      com.skt.opensocial.persistence.Activity activityDB =
          this.setActivityDBFromActivity(person, appId, activity);
      activityDB.setPerson(person);

      // auto increment "id" is the activity id
      Integer newId = (Integer) hs.save(activityDB);
      activityDB.setActivityId(newId.toString());

      // set up the posted time
      Long endTime = new Date().getTime();
      activityDB.setPostedTime(new Double(endTime - startTime));

      hs.saveOrUpdate(activityDB);

      // **** insert activity with mediaItems and templateParams separately ****//
      // create MediaItems of the Activity
      List<MediaItem> items = activity.getMediaItems();

      if (items != null) {
        for (MediaItem item : items) {
          com.skt.opensocial.persistence.ActivityMediaItem mediaItemDB =
              this.setMediaItemDBFromMediaItem(user, activityDB.getActivityId(), item);
          hs.saveOrUpdate(mediaItemDB);
        }
      }

      // create TemplateParams of the activity
      Map<String, String> params = activity.getTemplateParams();

      if (params != null) {
        Set<String> keys = params.keySet();
        for (String key : keys) {
          com.skt.opensocial.persistence.ActivityTemplateParam templateParamDB =
              this.setTemplateParamDBFromTemplateParma(
                  user, activityDB.getActivityId(), key, params.get(key));
          hs.saveOrUpdate(templateParamDB);
        }
      }

      tran.commit();

      return ImmediateFuture.newInstance(null);

    } catch (HibernateException e) {
      if (tran != null) tran.rollback();

      throw new ProtocolException(HttpServletResponse.SC_INTERNAL_SERVER_ERROR, e.getMessage(), e);
    }
  }
  @SuppressWarnings("unchecked")
  public Future<RestfulCollection<Activity>> getActivities(
      Set<UserId> userIds,
      GroupId groupId,
      String appId,
      Set<String> fields,
      CollectionOptions options,
      SecurityToken token)
      throws ProtocolException {

    List<Activity> activityList = Lists.newArrayList();

    Session hs = HibernateUtil.getSessionFactory().getCurrentSession();
    Transaction tran = null;

    try {

      Set<String> idSet = getIdSet(userIds, groupId, options, token);

      tran = hs.beginTransaction();

      for (String userId : idSet) {

        Person person = (Person) hs.get(Person.class, userId);

        if (person == null) continue;

        Set<com.skt.opensocial.persistence.Activity> activityDBSet = person.getActivities();

        for (com.skt.opensocial.persistence.Activity activityDB : activityDBSet) {
          if (appId != null) {
            if (activityDB.getAppId() != null && !activityDB.getAppId().equals(appId)) {
              continue;
            }
          }

          Activity activity = new ActivityImpl();
          activity = HDBTableMapper.getActivityFromActivityDB(activityDB);

          // *** get MediaItems ***//
          Criteria crit = hs.createCriteria(ActivityMediaItem.class);
          crit.setMaxResults(30);

          crit = hs.createCriteria(ActivityMediaItem.class);
          List<ActivityMediaItem> items = crit.add(Restrictions.eq("userId", userId)).list();
          if (items.size() > 0) {
            List<MediaItem> mediaItemList =
                HDBTableMapper.getMediaItemListFromMediaItemDBList(items);
            activity.setMediaItems(mediaItemList);
          }

          // *** get TemplateParams ***//
          Criteria crit2 = hs.createCriteria(ActivityMediaItem.class);
          crit2.setMaxResults(30);

          crit2 = hs.createCriteria(ActivityTemplateParam.class);
          List<ActivityTemplateParam> params = crit2.add(Restrictions.eq("userId", userId)).list();
          if (params.size() > 0) {
            Map<String, String> templateParamMap =
                HDBTableMapper.getTemplateParamMapFromTemplateParamDBList(params);
            activity.setTemplateParams(templateParamMap);
          }

          activityList.add(activity);
        }
      }

      tran.commit();

      return ImmediateFuture.newInstance(new RestfulCollection<Activity>(activityList));

    } catch (HibernateException e) {

      if (tran != null) tran.rollback();

      throw new ProtocolException(HttpServletResponse.SC_INTERNAL_SERVER_ERROR, e.getMessage(), e);
    }
  }
  @SuppressWarnings("unchecked")
  public Future<Void> deleteActivities(
      UserId userId, GroupId groupId, String appId, Set<String> activityIds, SecurityToken token)
      throws ProtocolException {

    Session hs = HibernateUtil.getSessionFactory().getCurrentSession();
    Transaction tran = null;

    try {

      Set<String> idSet = getIdSet(userId, groupId, token);

      tran = hs.beginTransaction();

      for (String user : idSet) {

        Person person = (Person) hs.get(Person.class, user);

        if (person == null) continue;

        Set<com.skt.opensocial.persistence.Activity> activityDBSet = person.getActivities();

        for (com.skt.opensocial.persistence.Activity activityDB : activityDBSet) {
          if (appId != null) {
            if (activityDB.getAppId() != null && !activityDB.getAppId().equals(appId)) {
              continue;
            }
          }

          Activity activity = new ActivityImpl();
          activity = HDBTableMapper.getActivityFromActivityDB(activityDB);

          String activityId = activity.getId();

          if (activityIds != null) {
            if (activityId != null && !activityIds.contains(activityId)) {
              continue;
            }
          }

          // *** delete MediaItems ***//
          Criteria crit = hs.createCriteria(ActivityMediaItem.class);

          // filer by an userId and an activityId
          crit = hs.createCriteria(ActivityMediaItem.class);
          List<ActivityMediaItem> items =
              crit.add(Restrictions.eq("userId", user))
                  .add(Restrictions.eq("activityId", activityId))
                  .list();

          for (ActivityMediaItem item : items) {
            hs.delete(item);
          }

          // *** delete TemplateParams ***//
          Criteria crit2 = hs.createCriteria(ActivityTemplateParam.class);

          // filer by an userId and an activityId
          crit2 = hs.createCriteria(ActivityTemplateParam.class);
          List<ActivityTemplateParam> params =
              crit2
                  .add(Restrictions.eq("userId", user))
                  .add(Restrictions.eq("activityId", activityId))
                  .list();

          for (ActivityTemplateParam param : params) {
            hs.delete(param);
          }

          // *** delete activity ***//
          hs.delete(activity);
        }
      }

      tran.commit();

      return ImmediateFuture.newInstance(null);
    } catch (HibernateException e) {
      if (tran != null) tran.rollback();

      throw new ProtocolException(HttpServletResponse.SC_INTERNAL_SERVER_ERROR, e.getMessage(), e);
    }
  }