code: public Object getParameter(String paramid, Object def) {
          final Object v = getParameter(paramid);
          if (v == null) {
              return def;
          } else {
              return v;
          }
      }
docs: Look for a parameter in the context with the given name. If parmeter is
  null, return def
  
  @param paramid parameter id
  @param def default value
  @return parameter value or def if null