Duplicator Element

[mstewart]

How do I duplicate I message using an xml schema element.

For example I have an output from an aggregator that gets passed to an outbound service.

The outbound service does some processing and eventually outputs to a channel . That's fine. Now I want to poll that channel in three places. I meant by poll is duplicate the final message. Maybe one for logging, another one for a custom service, another for another custom service.

I was expecting there's an element like <duplicator receive-from-channel="...."/>

Then I have three end receivers that will receive from duplicator
<receiver1 receive-from="duplicator" />
<receiver2 receive-from="duplicator" />
<receiver3 receive-from="duplicator" />

We have a splitter, aggreggator. Shouldn't we have a duplicator?

I wanna do it via the xml way

[oleg.zhurakousky]

Spring Integration messages are immutable by definition, which means that every endpoint (splitter, aggregator etc.) receives a new instance of the Message.
Read more here: http://static.springsource.org/sprin...essage-builder

So essentially you don't need to do anything with regard to duplication. Is that what you were looking for?

[jglynn]

It almost sounds as if you're simply unfamiliar with PublishSubscribeChannel?

[mstewart]

Thanks for the replies.

I believe the PublishSubscribeChannel seems to be the closer solution I was looking for I guess I was thinking differently. The only issue here is I need to implement a MessageHandler

With the ordinary channel, I just create a POJO with no dependencies or interfaces needed.

Why can't we have a channel that duplicates messages but without the need for a publish-subscribe channel? Or maybe not a channel...another element that duplicates messages declaratively?

I understand that messages are immutable. But I was looking for something in between a default channel and pub-sub channel. I just want a simple duplicator

[oleg.zhurakousky]

I am not sure what do you mean. The whole point of the channel abstraction is to manage HOW two+ endpoints talk to each other which means if A wants to talk to B and only B, then you POJOs representing A and B are connected with DirectChannel (as below)

<int:service-activator input-channel="inChannel" output-channel="someChannel">
     <bean class="foo.bar.Bar"/>
</int:service-activator>

<int:channel id="someChannel"/>

<int:service-activator input-channel="someChannel" output-channel="someOtherChannel">
     <bean class="foo.bar.Baz"/>
</int:service-activator>

However if more then one endpoint is interested in what A has to say, then you simply switch from DirectChannel to PubSubChannel

<int:service-activator input-channel="inChannel" output-channel="someChannel">
     <bean class="foo.bar.Bar"/>
</int:service-activator>

<int:publish-subscribe-channel id="someChannel"/>

<int:service-activator input-channel="someChannel" output-channel="someOtherChannel">
     <bean class="foo.bar.Baz"/>
</int:service-activator>

<int:service-activator input-channel="someChannel" output-channel="someOtherChannel">
     <bean class="foo.bar.Bazzzz"/>
</int:service-activator>

I am not sure what would duplicator do different?

Also, i would suggest to read up on Enterprise Integration Patterns http://www.eaipatterns.com/. This is where all these patterns come from