public RuleBase getRuleBase(String ruleBaseName) {
        ruleBaseName = RuleImporter.stripLastName(ruleBaseName);
        return ruleBases.get(ruleBaseName);
    }
Returns the rule base of the given name, or null if none.
The part of the name following the last dot (if any) is removed before lookup.
container-search/src/main/java/com/yahoo/prelude/semantics/SemanticSearcher.java