public interface MongoSearchRepository<T, ID> {
    List<T> searchByPage(String keyword, T example, Pageable page);
}

public class MongoSearchRepositoryImpl<T, ID> implements MongoSearchRepository<T, ID> {
    protected MongoOperations mongoOperations;

    @Autowired
    public MongoSearchRepositoryImpl(MongoOperations mongoOperations) {
        this.mongoOperations = mongoOperations;
    }

    @Override
    public List<T> searchByPage(String keyword, T example, Pageable page) {
        Query query = ...;

        return this.mongoOperations.find(
                    query,
                    this.getEntityInformation().getJavaType(),
                    this.getEntityInformation().getCollectionName());
}

@Repository
public interface ProductRepository
    extends MongoCrudRepository<Product, String>,
            MongoSearchRepository<Product, String>