protected final String conditionsToString(String conditionSeparator) {
        StringBuilder buffer = new StringBuilder();
        for (Iterator<Condition> i = conditionIterator(); i.hasNext(); ) {
            buffer.append(i.next().toString());
            if (i.hasNext())
                buffer.append(conditionSeparator);
        }
        return buffer.toString();
    }
Whether this should be output with parentheses, default is parent!=null
container-search/src/main/java/com/yahoo/prelude/semantics/rule/CompositeCondition.java