/**
   * Remove records telling what entity caps node a contact has.
   *
   * @param contact the contact
   */
  public void removeContactCapsNode(Contact contact) {
    Caps caps = null;
    String lastRemovedJid = null;

    Iterator<String> iter = userCaps.keySet().iterator();
    while (iter.hasNext()) {
      String jid = iter.next();

      if (StringUtils.parseBareAddress(jid).equals(contact.getAddress())) {
        caps = userCaps.get(jid);
        lastRemovedJid = jid;
        iter.remove();
      }
    }

    // fire only for the last one, at the end the event out
    // of the protocol will be one and for the contact
    if (caps != null) {
      UserCapsNodeListener[] listeners;
      synchronized (userCapsNodeListeners) {
        listeners = userCapsNodeListeners.toArray(NO_USER_CAPS_NODE_LISTENERS);
      }
      if (listeners.length != 0) {
        String nodeVer = caps.getNodeVer();

        for (UserCapsNodeListener listener : listeners)
          listener.userCapsNodeRemoved(lastRemovedJid, nodeVer, false);
      }
    }
  }
  /**
   * Add a record telling what entity caps node a user has.
   *
   * @param user the user (Full JID)
   * @param node the node (of the caps packet extension)
   * @param hash the hashing algorithm used to calculate <tt>ver</tt>
   * @param ver the version (of the caps packet extension)
   * @param ext the ext (of the caps packet extension)
   * @param online indicates if the user is online
   */
  private void addUserCapsNode(
      String user, String node, String hash, String ver, String ext, boolean online) {
    if ((user != null) && (node != null) && (hash != null) && (ver != null)) {
      Caps caps = userCaps.get(user);

      if ((caps == null)
          || !caps.node.equals(node)
          || !caps.hash.equals(hash)
          || !caps.ver.equals(ver)) {
        caps = new Caps(node, hash, ver, ext);

        userCaps.put(user, caps);
      } else return;

      // Fire userCapsNodeAdded.
      UserCapsNodeListener[] listeners;

      synchronized (userCapsNodeListeners) {
        listeners = userCapsNodeListeners.toArray(NO_USER_CAPS_NODE_LISTENERS);
      }
      if (listeners.length != 0) {
        String nodeVer = caps.getNodeVer();

        for (UserCapsNodeListener listener : listeners)
          listener.userCapsNodeAdded(user, nodeVer, online);
      }
    }
  }
  /**
   * Retrieve DiscoverInfo for a specific node.
   *
   * @param caps the <tt>Caps</tt> i.e. the node, the hash and the ver
   * @return The corresponding DiscoverInfo or null if none is known.
   */
  public static DiscoverInfo getDiscoverInfoByCaps(Caps caps) {
    synchronized (caps2discoverInfo) {
      DiscoverInfo discoverInfo = caps2discoverInfo.get(caps);

      /*
       * If we don't have the discoverInfo in the runtime cache yet, we
       * may have it remembered in a previous application instance.
       */
      if (discoverInfo == null) {
        ConfigurationService configurationService = getConfigService();
        String capsPropertyName = getCapsPropertyName(caps);
        String xml = configurationService.getString(capsPropertyName);

        if ((xml != null) && (xml.length() != 0)) {
          IQProvider discoverInfoProvider =
              (IQProvider)
                  ProviderManager.getInstance()
                      .getIQProvider("query", "http://jabber.org/protocol/disco#info");

          if (discoverInfoProvider != null) {
            XmlPullParser parser = new MXParser();

            try {
              parser.setFeature(XmlPullParser.FEATURE_PROCESS_NAMESPACES, true);
              parser.setInput(new StringReader(xml));
              // Start the parser.
              parser.next();
            } catch (XmlPullParserException xppex) {
              parser = null;
            } catch (IOException ioex) {
              parser = null;
            }

            if (parser != null) {
              try {
                discoverInfo = (DiscoverInfo) discoverInfoProvider.parseIQ(parser);
              } catch (Exception ex) {
              }

              if (discoverInfo != null) {
                if (caps.isValid(discoverInfo)) caps2discoverInfo.put(caps, discoverInfo);
                else {
                  logger.error(
                      "Invalid DiscoverInfo for " + caps.getNodeVer() + ": " + discoverInfo);
                  /*
                   * The discoverInfo doesn't seem valid
                   * according to the caps which means that we
                   * must have stored invalid information.
                   * Delete the invalid information in order
                   * to not try to validate it again.
                   */
                  configurationService.removeProperty(capsPropertyName);
                }
              }
            }
          }
        }
      }
      return discoverInfo;
    }
  }
  /**
   * Get the discover info given a user name. The discover info is returned if the user has a
   * node#ver associated with it and the node#ver has a discover info associated with it.
   *
   * @param user user name (Full JID)
   * @return the discovered info
   */
  public DiscoverInfo getDiscoverInfoByUser(String user) {
    Caps caps = userCaps.get(user);

    return (caps == null) ? null : getDiscoverInfoByCaps(caps);
  }
 /**
  * Gets the <tt>Caps</tt> i.e. the node, the hash and the ver of a user.
  *
  * @param user the user (Full JID)
  * @return the <tt>Caps</tt> i.e. the node, the hash and the ver of <tt>user</tt>
  */
 public Caps getCapsByUser(String user) {
   return userCaps.get(user);
 }