Eventing-style interactions involve a component that acts as a source or producer of events which are dispatched to a channel. In turn, consumer components are configured to listen on a channel for events. Similar to reference injection, a source component is injected with a producer proxy using the Fabric3 @Producer annotation. This proxy is responsible for dispatching messages to a channel. A component subscribes to a channel using a consumer method.
The following is an example of a source component with a an injected producer:
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import org.fabric3.api.annotation.Producer; @Component public class BuyComponent implements BuyService { @Producer(target="BuyChannel") private BuyChannel buyChannel; public void process() { BuyEvent event = //... buyChannel.publish(event);* } } |
The above example uses the default producer name "buyChannel". Alternatively, a name could be specified on the @producer is connected to the "BuyChannel" channel using the Producer annotation. The next excerpt subscribes to receive BuyEvents:
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import org.fabric3.api.annotation.Consumer; @Component public class BuyListener { @Consumer(source="buyChannelBuyChannel") public void onEvent(BuyEvent event) { // ... } } |
Producers, consumers, and channels Channels are configured in a composite using XML or a DSL:
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In XML: <composite ...> <channel <component name="BuyComponentBuyChannel"/> </composite> Using the DSL: <implementation.java .../> package f3; public class ChannelProvider { <producer name="buyChannel" target="BuyChannel"/> @Provides </component> public static <component name="BuyListener"> Composite testComposite() { <implementation.java .../> QName name = <consumer name="buyChannel" source="BuyChannel"/>new QName("urn:test", "ChannelComposite"); </component> ChannelDefinitionBuilder <channelchannelBuilder name= ChannelDefinitionBuilder.newBuilder("BuyChannel"/>); </composite> |
...
return CompositeBuilder.newBuilder(name).channel(channelBuilder.build()).build();
}
} |
For more details on using the DSL, see Annotations and the DSL.