public Selector addSelectionList(List<OutputAttribute> projectionList) {

        for (OutputAttribute outputAttribute : projectionList) {
            checkSelection(outputAttribute);
            this.selectionList.add(outputAttribute);
        }
        return this;
    }
Selector selecting query output stream attributes
modules/siddhi-query-api/src/main/java/io/siddhi/query/api/execution/query/selection/Selector.java