Fix: BoS prediction after inputting just once.

            if (!probabilityEntry.isValid()) {

                continue;

            }

            const int probability = probabilityEntry.hasHistoricalInfo() ?

                    0 : probabilityEntry.getProbability();

            int probability = NOT_A_PROBABILITY;

            if (probabilityEntry.hasHistoricalInfo()) {

                // TODO: Quit checking count here.

                // If count <= 1, the word can be an invaild word. The actual probability should

                // be checked using getWordAttributesInContext() in onVisitEntry().

                probability = probabilityEntry.getHistoricalInfo()->getCount() <= 1 ?

                        NOT_A_PROBABILITY : 0;

            } else {

                probability = probabilityEntry.getProbability();

            }

            listener->onVisitEntry(probability, entry.getWordId());

        }

    }