Module dk.cloudcreate.essentials.components.foundation
Package dk.cloudcreate.essentials.components.foundation.messaging.queue

Enum TransactionalMode

    • Enum Constant Detail

      • FullyTransactional

        public static final TransactionalMode FullyTransactional
        When using this mode all the queueing, de-queueing methods requires an existing UnitOfWork started prior to being called. The reason for this is that Queues are typically used together with the Inbox Outbox pattern, which benefits from including queueing/de-queueing together with other database entity modifying operations.
        When changing an entity and queueing/de-queueing happens in ONE shared transaction (NOTE this requires that the entity storage and the queue storage to use the same database - e.g. Postgresql or MongoDB) then the shared database transaction guarantees that all the data storage operations are committed or rollback as one

      • ManualAcknowledgement

        public static final TransactionalMode ManualAcknowledgement
        Certain NoSQL databases, such as MongoDB/DocumentDB, has limitations when performing multiple data storage operations within a transaction.
        For these cases you can configure the TransactionalMode as ManualAcknowledgement where queueing and de-queueing are performed using separate (single document) transactions and where acknowledging/retry are performed as separate transactions. Depending on the type of errors that can occur this MAY leave a dequeued message in a state of being marked as "being delivered" forever. Hence DurableQueues supporting this mode must ensure that they periodically discover messages that have been under delivery for a long time (aka. stuck messages or timed-out messages) and reset them in order for them to be redelivered.
        Example: 
        
 durableQueues.queueMessage(queueName, message);
 var msgUnderDelivery = durableQueues.getNextMessageReadyForDelivery(queueName);
 if (msgUnderDelivery.isPresent()) {
    try {
       handleMessage(msgUnderDelivery.get());
       durableQueues.acknowledgeMessageAsHandled(msgUnderDelivery.get().getId());
    } catch (Exception e) {
       durableQueues.retryMessage(msgUnderDelivery.get().getId(),
                                  e,
                                  Duration.ofMillis(500));
    }
 }

    • Method Detail

      • values

        public static TransactionalMode[] values()
        Returns an array containing the constants of this enum type, in the order they are declared. This method may be used to iterate over the constants as follows: 
        for (TransactionalMode c : TransactionalMode.values())
    System.out.println(c);
        Returns:
        an array containing the constants of this enum type, in the order they are declared

      • valueOf

        public static TransactionalMode valueOf​(String name)
        Returns the enum constant of this type with the specified name. The string must match exactly an identifier used to declare an enum constant in this type. (Extraneous whitespace characters are not permitted.)
        Parameters:
        name - the name of the enum constant to be returned.
        Returns:
        the enum constant with the specified name
        Throws:
        IllegalArgumentException - if this enum type has no constant with the specified name
        NullPointerException - if the argument is null