private void loadSqls(Map<String, SqlConfig> sqls) {
        this.sqlExpressionMap = new HashMap<String, SqlExpression>();
        for ( String sqlId : sqls.keySet() ) {
            SqlConfig sqlConfig = sqls.get(sqlId);
            SqlExpression sqlExpression = expressionParser.parseExpression(sqlConfig);
            sqlExpressionMap.put(sqlId, sqlExpression);
        }
    }