private void connectItems() {
        for (ConnectedItem entry : connectedItems) {
            TaggableItem to = identifiedItems.get(entry.toId);
            if (to == null)
                throw new IllegalArgumentException("Item '" + entry.fromItem +
                                                   "' was specified to connect to item with ID " + entry.toId +
                                                   ", which does not exist in the query.");
            entry.fromItem.setConnectivity((Item) to, entry.weight);
        }
    }
Translates a list of grouping requests on JSON form to a list in the grouping language form
container-search/src/main/java/com/yahoo/search/query/SelectParser.java