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The processor pattern using Camel

Using the processor pattern, you can consume on a channel using a Camel component, and produce on a channel using another Camel component. In that case, the headers present in the incoming metadata will be forwarded in the outgoing metadata.

Example

Let’s imagine you want to read messages from a Nats subject, process it and produce a message on a Kafka topic.

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mp.messaging.incoming.mynatssubject.connector=smallrye-camel # <1>
mp.messaging.incoming.mynatssubject.endpoint-uri=nats:mynatssubject # <2>
mp.messaging.outgoing.mykafkatopic.connector=smallrye-camel # <3>
mp.messaging.outgoing.mykafkatopic.endpoint-uri=kafka:mykafkatopic# <4>

camel.component.nats.servers=127.0.0.1:5555 # <5>
camel.component.kafka.brokers=127.0.0.1:9092 # <6>
1. Sets the connector for the mynatssubject channel 2. Configures the endpoint-uri for nats subject 3. Sets the connector for the mykafkatopic channel 4. Configures the endpoint-uri for the kafka topic 5. Sets the URL of the nats server to use 6. Sets the URL of a kafka broker to use

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package camel.processor;

import javax.enterprise.context.ApplicationScoped;

import org.eclipse.microprofile.reactive.messaging.Incoming;
import org.eclipse.microprofile.reactive.messaging.Outgoing;

@ApplicationScoped
public class CamelProcessor {

    @Incoming("mynatssubject")
    @Outgoing("mykafkatopic")
    public byte[] process(byte[] message) {
        // do some logic
        return message;
    }

}