JCache – CacheLoader ve CacheWriter Kullanmak

public interface CacheLoader<K, V> { (1)

  V load(K key); (2)
  Map<K, V> loadAll(Iterable<? extends K> keys); (3)

}

public class BackupReader implements CacheLoader<Long, Book> {

 private final EntityManager em = //..;

 private static final Logger logger = //..


 @Override (1)
 public Book load(Long isbn) {

    logger.info(isbn + " Cache içinde bulunamadı.");
    logger.info(isbn + " db'den yükleniyor.");
    Book found = em.find(Book.class, isbn);

    if (Objects.nonNull(found))
        logger.info(isbn + " db'den yüklendi.");
    else
        logger.info(isbn + " db'de de bulunamadı.");
    return found;


 }

 @Override (2)
 public Map<Long, Book> loadAll(Iterable<? extends Long> keys){

    Map<Long, Book> allBooks = new HashMap<>();

    for (Long key : keys) {
        allBooks.put(key, load(key));
    }

    return allBooks;
 }
}

public interface CacheWriter<K, V> {
 void write(Cache.Entry<K,V> entry); (1)
 void writeAll(Collection<Cache.Entry<K,V>> entries); (2)
 void delete(Object key); (3)
 void deleteAll(Collection<?> keys); (4)
}

public class BackupWriter implements CacheWriter<Long, Book> {

 private final EntityManager em = //..
 private static final Logger logger = //..

 @Override
 public void write(Cache.Entry<Long,Book> entry){ (1)

    Long isbn = entry.getKey();
    Book book = entry.getValue();

    logger.info(isbn + " db'ye yazılıyor");

    em.getTransaction().begin();
        em.merge(book);
    em.getTransaction().commit();

    logger.info(isbn + " db'ye yazıldı");
 }

 @Override
 public void writeAll(Collection<Cache.Entry<Long,Book>> entries){
    entries.forEach(this::write); (2)
 }

 @Override
 public void delete(Object isbn) { (3)
    Book found = em.find(Book.class, isbn);

    if (Objects.nonNull(found)) {
        logger.info(isbn + " db'den siliniyor.");

        em.getTransaction().begin();
            em.remove(found);
        em.getTransaction().commit();

        logger.info(isbn + " db'den silindi.");
    }
 }

 @Override
 public void deleteAll(Collection<?> keys) { (4)
    keys.forEach(this::delete);
 }
}