public void addItem(Item item, TermType termType) {
        Item root = query.getModel().getQueryTree().getRoot();
        if (root == null)
            query.getModel().getQueryTree().setRoot(item);
        else
            query.getModel().getQueryTree().setRoot(combineItems(root, item, termType));
    }
Adds an item to the query being evaluated in a way consistent with the query type
container-search/src/main/java/com/yahoo/prelude/semantics/engine/Evaluation.java