private StoredValues singleValue(final int trimmedSize, final boolean trimTop) {
                        final Iterable<StoredValues> values = getStoredValueIterable(trimmedSize, trimTop);
                        final Iterator<StoredValues> iterator = values.iterator();
                        if (iterator.hasNext()) {
                            return iterator.next();
                        }
                        return null;
                    }
Set to false if we don't want to keep looking through the store.
stroom-query/stroom-query-common/src/main/java/stroom/query/common/v2/MapDataStore.java