protected String getUserPreference(String key) {
    String value = StringPool.BLANK;

    if (!hasUserPreferences()) {
      return value;
    }

    value =
        _portalPreferences.getValue(CustomizedPages.namespacePlid(getPlid()), key, StringPool.NULL);

    if (!value.equals(StringPool.NULL)) {
      return value;
    }

    value = getTypeSettingsProperty(key);

    if (Validator.isNull(value)) {
      return value;
    }

    List<String> newPortletIds = new ArrayList<>();

    PermissionChecker permissionChecker = PermissionThreadLocal.getPermissionChecker();

    String[] portletIds = StringUtil.split(value);

    for (String portletId : portletIds) {
      try {
        if (!PortletPermissionUtil.contains(
            permissionChecker, getLayout(), portletId, ActionKeys.VIEW, true)) {

          continue;
        }

        String rootPortletId = PortletConstants.getRootPortletId(portletId);

        if (!PortletPermissionUtil.contains(
            permissionChecker, rootPortletId, ActionKeys.ADD_TO_PAGE)) {

          continue;
        }
      } catch (Exception e) {
        _log.error(e, e);
      }

      String newPortletId = null;

      boolean preferencesUniquePerLayout = false;

      try {
        Portlet portlet = PortletLocalServiceUtil.getPortletById(getCompanyId(), portletId);

        preferencesUniquePerLayout = portlet.isPreferencesUniquePerLayout();
      } catch (SystemException se) {
        _log.error(se, se);
      }

      if (PortletConstants.hasInstanceId(portletId) || preferencesUniquePerLayout) {

        String instanceId = null;

        if (PortletConstants.hasInstanceId(portletId)) {
          instanceId = PortletConstants.generateInstanceId();
        }

        newPortletId =
            PortletConstants.assemblePortletId(
                portletId, _portalPreferences.getUserId(), instanceId);

        copyPreferences(_portalPreferences.getUserId(), portletId, newPortletId);

        copyResourcePermissions(portletId, newPortletId);
      } else {
        newPortletId = portletId;
      }

      newPortletIds.add(newPortletId);
    }

    value = StringUtil.merge(newPortletIds);

    setUserPreference(key, value);

    return value;
  }
  protected String addPortletId(
      long userId,
      String portletId,
      String columnId,
      int columnPos,
      boolean checkPermission,
      boolean strictHasPortlet) {

    portletId = JS.getSafeName(portletId);

    Layout layout = getLayout();

    Portlet portlet = null;

    try {
      portlet = PortletLocalServiceUtil.getPortletById(layout.getCompanyId(), portletId);

      if (portlet == null) {
        if (_log.isWarnEnabled()) {
          _log.warn("Portlet " + portletId + " cannot be added because it is not registered");
        }

        return null;
      }

      PermissionChecker permissionChecker = PermissionThreadLocal.getPermissionChecker();

      if (checkPermission
          && !PortletPermissionUtil.contains(
              permissionChecker, layout, portlet, ActionKeys.ADD_TO_PAGE)) {

        return null;
      }
    } catch (Exception e) {
      _log.error(e, e);
    }

    if (portlet.isSystem()) {
      return null;
    }

    if (portlet.isInstanceable() && !PortletConstants.hasInstanceId(portletId)) {

      portletId =
          PortletConstants.assemblePortletId(portletId, PortletConstants.generateInstanceId());
    }

    if (hasPortletId(portletId, strictHasPortlet)) {
      return null;
    }

    if (columnId == null) {
      LayoutTemplate layoutTemplate = getLayoutTemplate();

      List<String> columns = layoutTemplate.getColumns();

      if (!columns.isEmpty()) {
        columnId = columns.get(0);
      }
    }

    if (columnId == null) {
      return null;
    }

    if (isCustomizable()) {
      if (isColumnDisabled(columnId)) {
        return null;
      }

      if ((PortletConstants.hasInstanceId(portletId) || portlet.isPreferencesUniquePerLayout())
          && hasUserPreferences()) {

        portletId = PortletConstants.assemblePortletId(portletId, userId);
      }
    }

    String columnValue = StringPool.BLANK;

    if (hasUserPreferences()) {
      columnValue = getUserPreference(columnId);
    } else {
      columnValue = getTypeSettingsProperty(columnId);
    }

    if ((columnValue == null) && columnId.startsWith(_NESTED_PORTLETS_NAMESPACE)) {

      addNestedColumn(columnId);
    }

    if (columnPos >= 0) {
      List<String> portletIds = ListUtil.fromArray(StringUtil.split(columnValue));

      if (columnPos <= portletIds.size()) {
        portletIds.add(columnPos, portletId);
      } else {
        portletIds.add(portletId);
      }

      columnValue = StringUtil.merge(portletIds);
    } else {
      columnValue = StringUtil.add(columnValue, portletId);
    }

    if (hasUserPreferences()) {
      setUserPreference(columnId, columnValue);
    } else {
      setTypeSettingsProperty(columnId, columnValue);
    }

    try {
      if (_enablePortletLayoutListener && !portlet.isUndeployedPortlet()) {

        PortletLayoutListener portletLayoutListener = portlet.getPortletLayoutListenerInstance();

        if (portletLayoutListener != null) {
          portletLayoutListener.onAddToLayout(portletId, layout.getPlid());
        }
      }
    } catch (Exception e) {
      _log.error("Unable to fire portlet layout listener event", e);
    }

    return portletId;
  }