public boolean resolveExtends(CdlDocument document)
public void  resolveExtends(CdlDocument document)
    public boolean resolveExtends(CdlDocument document)            throws CdlException {        ToplevelList system = document.getSystem();        if (system != null) {            PropertyList newSystem = resolveChildExtends(system);            document.replaceSystem((ToplevelList) newSystem);            ResolveEnum state = newSystem.aggregateResolutionState();            if (!state.isParseTimeResolutionComplete()) {                throw new CdlInternalErrorException("Incomplete parse time resolution");            }            return true;        } else {            return false;        }    }