public Index addCommand(String indexName, String commandString) {
        Index index = getOrCreateIndex(indexName);
        index.addCommand(commandString);
        if (index.isDefaultPosition()) {
            defaultPosition = index.getName();
        }
        return index;
    }
Returns the indices of this as a map
container-search/src/main/java/com/yahoo/prelude/SearchDefinition.java