code: private void stopPondLife(int id)
      {
          PondLife pl = null;
          synchronized(this)
          {
              pl=_pondLife[id];
              if (pl!=null)
              {
                  _pondLife[id]=null;
                  _index[--_size]=id;
                  if (_available>_size)
                      _available=_size;
              }
          }
          if (pl!=null)
              pl.leavePool();
      }
docs: /* ------------------------------------------------------------