Different expiration time for message groups in aggegator

[Diego Bravo]

Hello,

I'm using an Aggregator (using the default in memory storage) as a sort of temporary repository useful for the logic of my flow.

Now I need to establish different expiration times for the message groups (those times will depend on some application specific traits of the stored messages.) At first I thought in extending SimpleMessageGroup and overriding the getTimestamp() method to some future time (and expiring the MessageStore with a timeout of zero, every second.) The problem is that I can't find a way to inject such a derived class.

Looking in SimpleMessageStore I've found:

	public MessageGroup getMessageGroup(Object groupId) {
		Assert.notNull(groupId, "'groupId' must not be null");
		SimpleMessageGroup group = groupIdToMessageGroup.get(groupId);
		if (group == null) {
			return new SimpleMessageGroup(groupId);
		}
		return new SimpleMessageGroup(group);
	}

Any suggestion? Maybe override SimpleMessageStore.getMessageGroup()?

Thanks!

[Diego Bravo]

Hello, some idea? or I'm missing something?

[Gary Russell]

No, you are not missing anything; we would need to add a strategy to allow the creation of custom Message Groups (e.g. MessageGroupCreator). But, this has implications on MessageGroupStores too, in that we would need to expose some mechanism to persist any metadata that the custom group might need to persist over JVM restarts.

Please go ahead and open an Improvement JIRA.

[Diego Bravo]

Thank you Gary.

https://jira.springsource.org/browse/INT-2510

Some idea for a workaround?

[Gary Russell]

Maybe you could write a custom MessageGroupStore (maybe subclass one of the standard ones, such as SimpleMessageStore), and override expireMessageGroups() to use a custom algorithm?