How to use

org.eclipse.persistence.descriptors.TimestampLockingPolicy

constructor

/**
 * PUBLIC:
 * Set the locking policy to use timestamp version locking.
 * This updates the timestamp field on all updates, first comparing that the field has not changed to detect locking conflicts.
 * Note: many database have limited precision of timestamps which can be an issue is highly concurrent systems.
 *
 * The parameter 'shouldStoreInCache' configures the version lock value to be stored in the cache or in the object.
 * Note: if using a stateless model where the object can be passed to a client and then later updated in a different transaction context,
 * then the version lock value should not be stored in the cache, but in the object to ensure it is the correct value for that object.
 * @see VersionLockingPolicy
 */
public void useTimestampLocking(String writeLockFieldName, boolean shouldStoreInCache) {
  TimestampLockingPolicy policy = new TimestampLockingPolicy(writeLockFieldName);
  if (shouldStoreInCache) {
    policy.storeInCache();
  } else {
    policy.storeInObject();
  }
  setOptimisticLockingPolicy(policy);
}

/**
 * PUBLIC:
 * Set the locking policy to use timestamp version locking.
 * This updates the timestamp field on all updates, first comparing that the field has not changed to detect locking conflicts.
 * Note: many database have limited precision of timestamps which can be an issue is highly concurrent systems.
 *
 * The parameter 'shouldStoreInCache' configures the version lock value to be stored in the cache or in the object.
 * Note: if using a stateless model where the object can be passed to a client and then later updated in a different transaction context,
 * then the version lock value should not be stored in the cache, but in the object to ensure it is the correct value for that object.
 * @see VersionLockingPolicy
 */
public void useTimestampLocking(String writeLockFieldName, boolean shouldStoreInCache) {
  TimestampLockingPolicy policy = new TimestampLockingPolicy(writeLockFieldName);
  if (shouldStoreInCache) {
    policy.storeInCache();
  } else {
    policy.storeInObject();
  }
  setOptimisticLockingPolicy(policy);
}

/**
 * PUBLIC:
 * Set the locking policy to use timestamp version locking.
 * This updates the timestamp field on all updates, first comparing that the field has not changed to detect locking conflicts.
 * Note: many database have limited precision of timestamps which can be an issue is highly concurrent systems.
 *
 * The parameter 'shouldStoreInCache' configures the version lock value to be stored in the cache or in the object.
 * Note: if using a stateless model where the object can be passed to a client and then later updated in a different transaction context,
 * then the version lock value should not be stored in the cache, but in the object to ensure it is the correct value for that object.
 * @see VersionLockingPolicy
 */
public void useTimestampLocking(String writeLockFieldName, boolean shouldStoreInCache) {
  TimestampLockingPolicy policy = new TimestampLockingPolicy(writeLockFieldName);
  if (shouldStoreInCache) {
    policy.storeInCache();
  } else {
    policy.storeInObject();
  }
  setOptimisticLockingPolicy(policy);
}

  /**
   * INTERNAL:
   * Process a version accessor.
   */
  @Override
  public void process() {
    // This will initialize the m_field variable. Accessible through getField().
    super.process();
    
    // Process an @Version or version element if there is one.
    if (getDescriptor().usesOptimisticLocking()) {
      // Ignore the version locking if it is already set.
      getLogger().logConfigMessage(MetadataLogger.IGNORE_VERSION_LOCKING, this);
    } else {
      MetadataClass lockType = getRawClass();
      getDatabaseField().setTypeName(getJavaClassName(lockType));

      if (isValidVersionLockingType(lockType) || isValidTimestampVersionLockingType(lockType)) {
        for (MetadataDescriptor owningDescriptor : getOwningDescriptors()) {
          VersionLockingPolicy policy = isValidVersionLockingType(lockType) ? new VersionLockingPolicy(getDatabaseField()) : new TimestampLockingPolicy(getDatabaseField());  
          policy.storeInObject();
          policy.setIsCascaded(getDescriptor().usesCascadedOptimisticLocking());
          owningDescriptor.setOptimisticLockingPolicy(policy);
        }
      } else {
        throw ValidationException.invalidTypeForVersionAttribute(getAttributeName(), lockType, getJavaClass());
      }
    }
  }
}