String parserConfPath = "../test/squall/unit_tests/confs/0_1G_tpch7_ncl";
ParserMain pm = new ParserMain();
Map map = pm.createConfig(parserConfPath);
SQLVisitor parsedQuery = ParserUtil.parseQuery(map);
ProjGlobalCollect instance = new ProjGlobalCollect(parsedQuery.getSelectItems(), parsedQuery.getWhereExpr());
instance.process();
//getting results
List<Expression> listExpr = instance.getExprList();
List<OrExpression> orListExpr = instance.getOrExprs();