final Object mutex = "";
final Sink<RippleList> resultTee = new Tee<RippleList>
(resultBuffer, queryResultHistory);
recognizerAdapter = new RecognizerAdapter(queryEngine.getErrorPrintStream()) {
protected void handleQuery(ListAST ast) throws RippleException {
synchronized (mutex) {
queryResultHistory.advance();
new RippleQueryCmd(ast, resultTee).execute(queryEngine, connection);