DatabaseWrapper.java 文件源码

/**
 * @return The managed version of the provided entity (with set autogenerated values for example).
 */
@Nonnull
@CheckReturnValue
//returns a sauced entity
public <E extends SaucedEntity<I, E>, I extends Serializable> E merge(@Nonnull final E entity)
        throws DatabaseException {
    final EntityManager em = this.databaseConnection.getEntityManager();
    try {
        em.getTransaction().begin();
        final E managedEntity = em.merge(entity);
        em.getTransaction().commit();
        return managedEntity
                .setSauce(this);
    } catch (final PersistenceException e) {
        final String message = String.format("Failed to merge entity %s on DB %s",
                entity.toString(), this.databaseConnection.getName());
        throw new DatabaseException(message, e);
    } finally {
        em.close();
    }
}