/**
   * Process list of event objects. Checks whether message source contact already exist for this
   * event object, if yes just update it with the new values (not sure whether we should do this, as
   * it may bring old messages) and if status of provider is changed, init its details, updates its
   * capabilities. It still adds the found messages source contact to the list of the new contacts,
   * as later we will detect this and fire update event. If nothing found a new contact is created.
   *
   * @param res list of event
   * @param cachedRecentMessages list of newly created source contacts or already existed but
   *     updated with corresponding event object
   * @param isStatusChanged whether provider status changed and we are processing
   */
  private void processEventObjects(
      Collection<EventObject> res,
      List<ComparableEvtObj> cachedRecentMessages,
      boolean isStatusChanged) {
    for (EventObject obj : res) {
      ComparableEvtObj oldMsg = findRecentMessage(obj, recentMessages);

      if (oldMsg != null) {
        oldMsg.update(obj); // update

        if (isStatusChanged && recentQuery != null) recentQuery.updateCapabilities(oldMsg, obj);

        // we still add it to cachedRecentMessages
        // later we will find it is duplicate and will fire
        // update event
        if (!cachedRecentMessages.contains(oldMsg)) cachedRecentMessages.add(oldMsg);

        continue;
      }

      oldMsg = findRecentMessage(obj, cachedRecentMessages);

      if (oldMsg == null) {
        oldMsg = new ComparableEvtObj(obj);

        if (isStatusChanged && recentQuery != null) recentQuery.updateCapabilities(oldMsg, obj);

        cachedRecentMessages.add(oldMsg);
      }
    }
  }
  /**
   * Updates the contact sources in the recent query if any. Done here in order to sync with
   * recentMessages instance, and to check for already existing instances of contact sources.
   * Normally called from the query.
   */
  public void updateRecentMessages() {
    if (recentQuery == null) return;

    synchronized (recentMessages) {
      List<SourceContact> currentContactsInQuery = recentQuery.getQueryResults();

      for (ComparableEvtObj evtObj : recentMessages) {
        // the contains will use the correct equals method of
        // the object evtObj
        if (!currentContactsInQuery.contains(evtObj)) {
          MessageSourceContact newSourceContact =
              new MessageSourceContact(evtObj.getEventObject(), MessageSourceService.this);
          newSourceContact.initDetails(evtObj.getEventObject());

          recentQuery.addQueryResult(newSourceContact);
        }
      }
    }
  }
  /**
   * Add the ComparableEvtObj, newly added will fire new, for existing fire update and when trimming
   * the list to desired length fire remove for those that were removed
   *
   * @param contactsToAdd
   */
  private void addNewRecentMessages(List<ComparableEvtObj> contactsToAdd) {
    // now find object to fire new, and object to fire remove
    // let us find duplicates and fire update
    List<ComparableEvtObj> duplicates = new ArrayList<ComparableEvtObj>();
    for (ComparableEvtObj msgToAdd : contactsToAdd) {
      if (recentMessages.contains(msgToAdd)) {
        duplicates.add(msgToAdd);

        // save update
        updateRecentMessageToHistory(msgToAdd);
      }
    }
    recentMessages.removeAll(duplicates);

    // now contacts to add has no duplicates, add them all
    boolean changed = recentMessages.addAll(contactsToAdd);

    if (changed) {
      Collections.sort(recentMessages);

      if (recentQuery != null) {
        for (ComparableEvtObj obj : duplicates)
          recentQuery.updateContact(obj, obj.getEventObject());
      }
    }

    if (!recentMessages.isEmpty())
      oldestRecentMessage = recentMessages.get(recentMessages.size() - 1).getTimestamp();

    // trim
    List<ComparableEvtObj> removedItems = null;
    if (recentMessages.size() > numberOfMessages) {
      removedItems =
          new ArrayList<ComparableEvtObj>(
              recentMessages.subList(numberOfMessages, recentMessages.size()));

      recentMessages.removeAll(removedItems);
    }

    if (recentQuery != null) {
      // now fire, removed for all that were in the list
      // and now are removed after trim
      if (removedItems != null) {
        for (ComparableEvtObj msc : removedItems) {
          if (!contactsToAdd.contains(msc)) recentQuery.fireContactRemoved(msc);
        }
      }

      // fire new for all that were added, and not removed after trim
      for (ComparableEvtObj msc : contactsToAdd) {
        if ((removedItems == null || !removedItems.contains(msc)) && !duplicates.contains(msc)) {
          MessageSourceContact newSourceContact =
              new MessageSourceContact(msc.getEventObject(), MessageSourceService.this);
          newSourceContact.initDetails(msc.getEventObject());

          recentQuery.addQueryResult(newSourceContact);
        }
      }

      // if recent messages were changed, indexes have change lets
      // fire event for the last element which will reorder the whole
      // group if needed.
      if (changed) recentQuery.fireContactChanged(recentMessages.get(recentMessages.size() - 1));
    }
  }