private void addPageTemplateSources(Set<Source> pageSources,Query query) {
        for (Source pageSource : pageSources) {
            if (pageSource == Source.any) continue;
            query.getModel().getSources().add(pageSource.getName());
            addParameters(pageSource,query);
        }
    }
Sets query.getModel().getSources() to the right value and add source parameters specified in templates
container-search/src/main/java/com/yahoo/search/pagetemplates/PageTemplateSearcher.java