DatabaseWrapper.java 文件源码

/**
 * So you want to load an entity, set some data, and save it again, without detaching it from the persistence
 * context and without bothering with the EntityManager?
 * Look no further! Functional programming to the rescue, just pass a function that does the required transformation
 * on the entity.
 * <p>
 * NOTE that this will create a new instance of the entity if it does not exist yet.
 *
 */
@Nonnull
public <E extends SaucedEntity<I, E>, I extends Serializable> E findApplyAndMerge(@Nonnull final Transfiguration<I, E> transfiguration)
        throws DatabaseException {
    final EntityManager em = this.databaseConnection.getEntityManager();
    try {
        return this.lockedWrappedTransformFunc(transfiguration).apply(em);
    } catch (final PersistenceException e) {
        final String message = String.format("Failed to find, apply and merge entity id %s of class %s on DB %s",
                transfiguration.key.id.toString(), transfiguration.key.clazz.getName(),
                this.databaseConnection.getName());
        throw new DatabaseException(message, e);
    } finally {
        em.close();
    }
}