docs: public void addThisMessageFilter(BaseMessageFilter filter)
      {
          if (m_filter == null)
              m_filter = filter;
          else
          {
              if (m_filter instanceof BaseMessageFilter)
              {
                  BaseMessageFilter filterFirst = (BaseMessageFilter)m_filter;
                  m_filter = new Hashtable<String,Object>();
                  ((Map)m_filter).put(filterFirst.getFilterID(), filterFirst);
              }
              ((Map)m_filter).put(filter.getFilterID(), filter);
          }
      }