code: protected boolean pushNamespace(String prefix, String uri)
      {
          try
          {
              if (m_prefixMap.pushNamespace(
                  prefix, uri, m_elemContext.m_currentElemDepth))
              {
                  startPrefixMapping(prefix, uri);
                  return true;
              }
          }
          catch (SAXException e)
          {
              // falls through
          }
          return false;
      }
docs: From XSLTC
  Declare a prefix to point to a namespace URI. Inform SAX handler
  if this is a new prefix mapping.