Broadcast

Experimental

@Broadcast is an experimental feature.

By default, messages transiting in a channel are only dispatched to a single consumer. Having multiple consumers is considered as an error, and is reported at deployment time.

The Broadcast annotation changes this behavior and indicates that messages transiting in the channel are dispatched to all the consumers. @Broadcast must be used with the @Outgoing annotation:

@Incoming("in")
@Outgoing("out")
@Broadcast
public int increment(int i) {
    return i + 1;
}

@Incoming("out")
public void consume1(int i) {
    //...
}

@Incoming("out")
public void consume2(int i) {
    //...
}

In the previous example, both consumers get the messages.

You can also control the number of consumers to wait before starting to dispatch the messages. This allows waiting for the complete graph to be weaved:

@Incoming("in")
@Outgoing("out")
@Broadcast(2)
public int increment(int i) {
    return i + 1;
}

@Incoming("out")
public void consume1(int i) {
    //...
}

@Incoming("out")
public void consume2(int i) {
    //...
}
Inbound connectors also support a broadcast attribute that allows broadcasting the messages to multiple downstream subscribers.

Use with Emitter

For details on how to use @Broadcast with Emitter see the documentation.