@Override
    protected Item parseItems() {
        throw new RuntimeException(); // Not used since this overrides the parse method to delegate tokenization
    }
A parser which delegates all tokenization and processing to the linguistics component.
The full string is given as-is to the linguistics component for tokenization, and
what comes back is assumes fully processed including stemming (if applicable).
The returned tokens are collected into a single parent item.

@author bratseth
container-search/src/main/java/com/yahoo/prelude/query/parser/LinguisticsParser.java