io.joynr.messaging.persistence

Interface MessagePersister

All Known Implementing Classes:

NoOpMessagePersister

public interface MessagePersister

You can provide an implementation of this interface in order to be given the chance to persist messages being added to the MessageQueue so that if the joynr runtime quits unexpectedly, the messages in the queue are not lost and can be restored on the next start of the runtime.

Method Summary

Modifier and Type	Method and Description
Set<DelayableImmutableMessage>	fetchAll(String messageQueueId) Fetches all messages from persistence which have not yet been remove(String,DelayableImmutableMessage).
boolean	persist(String messageQueueId, DelayableImmutableMessage message) Called with the message to be persisted.
void	remove(String messageQueueId, DelayableImmutableMessage message) Called once the message queue has actually processed the message previously added to the persistence by calling persist(String,DelayableImmutableMessage).

Method Detail

persist

boolean persist(String messageQueueId,
                DelayableImmutableMessage message)

Called with the message to be persisted. If the implementation does not want to persist the message, it should return false. Implementations of this method can block until the persisting was successful, but be aware that this might impact performance.

Parameters:

messageQueueId - the unique ID of the message queue for which the message is being persisted

message - the message which is a candidate for persisting

Returns:

true if the message is persisted, false if not.

fetchAll

Set<DelayableImmutableMessage> fetchAll(String messageQueueId)

Fetches all messages from persistence which have not yet been remove(String,DelayableImmutableMessage). The MessageQueue will call this during startup to fetch any messages which were persisted but not consumed during a previous lifetime of the joynr runtime in order to re-add them to the queue.

Parameters:

messageQueueId - the ID of the message queue for which to fetch the persisted messages.

Returns:

the set of messages which were previously added by the IDed message queue, but were not consumed.

remove

void remove(String messageQueueId,
            DelayableImmutableMessage message)

Called once the message queue has actually processed the message previously added to the persistence by calling persist(String,DelayableImmutableMessage). The implementation of this method should ensure that the message is actually removed from the persistence, and should block until this has been done successfully.

Parameters:

messageQueueId - the ID of the message queue which consumed the message.

message - the message which has been consumed by the queue and should be removed from persistence.