JpaLockingStrategy.java 文件源码

/**
 * Acquire the lock object.
 *
 * @param em the em
 * @param lock the lock
 * @return true, if successful
 */
private boolean acquire(final EntityManager em, final Lock lock) {
    lock.setUniqueId(uniqueId);
    if (lockTimeout > 0) {
        final Calendar cal = Calendar.getInstance();
        cal.add(Calendar.SECOND, lockTimeout);
        lock.setExpirationDate(cal.getTime());
    } else {
        lock.setExpirationDate(null);
    }
    boolean success = false;
    try {
        if (lock.getApplicationId() != null) {
            em.merge(lock);
        } else {
            lock.setApplicationId(applicationId);
            em.persist(lock);
        }
        success = true;
    } catch (final PersistenceException e) {
        success = false;
        if (logger.isDebugEnabled()) {
            logger.debug("{} could not obtain {} lock.", uniqueId, applicationId, e);
        } else {
            logger.info("{} could not obtain {} lock.", uniqueId, applicationId);
        }
    }
    return success;
}