WireTap configuration in Spring Integration Java D

Question

I've added WireTap configuration to my Spring Integration Java DSL.

I reviewed discussion What is the equivalent of logging-channel-adapter in java DSL and now my main Java Config file looks like

@Configuration
@Import(LoggerConfiguration.class)
@EnableIntegration
public class ProcessorConfiguration {

    @Autowired
    private WireTap wireTap;

    @Bean
    public QueueChannel inputChannel() {
        return MessageChannels.queue(500)
            .interceptor(wireTap)
            .get();
    }

    @Bean
    public PublishSubscribeChannel outputChannel() {
        return MessageChannels.publishSubscribe()
            .interceptor(wireTap)
            .get();
    }
    ...
}

And LoggerConfiguration is

@Configuration
public class LoggerConfiguration {

    public static final LoggingHandler.Level INFO = LoggingHandler.Level.INFO;

    @Bean
    public WireTap wireTap() {
        return new WireTap(loggerChannel());
    }

    @Bean
    public IntegrationFlow loggerChain() {
        return IntegrationFlows.from(loggerChannel())
               .handle(loggerHandler())
               .get();
    }

    @Bean
    public MessageChannel loggerChannel() {
        return MessageChannels.direct().get();
    }

    public MessageHandler loggerHandler() {
        LoggingHandler loggingHandler = new LoggingHandler(INFO.name());
        ...  
        return loggingHandler;
   }
}

All of thes tones(!) of code ONLY to reach what I had in XML configuration in these simple lines

<int:channel id="inputChannel">
    <int:queue capacity="500"/>
    <int:interceptors>
        <int:wire-tap channel="logger"/>
    </int:interceptors>
</int:channel>

<int:publish-subscribe-channel id="outputChannel">
    <int:interceptors>
        <int:wire-tap channel="logger"/>
    </int:interceptors>
</int:publish-subscribe-channel>

<int:logging-channel-adapter id="logger" log-full-message="true" level="INFO"/>

How can I configure wireTaps in Java DSL less verbose and simple?

Answer 1

Since you really don't have there a flow you can just end up with the:

@ServiceActivator(inputChannel = "loggerChannel") 
public MessageHandler loggerHandler() {
     LoggingHandler loggingHandler = new LoggingHandler(INFO.name());
     ...  
     return loggingHandler;
}

No reason to declare a "verbose" IntegrationFlow if there is only the simple handle logic.

The Java DSL really can be combined with the raw Java & Annotation configuration and even the XML configs can live there as well.

WireTap may not be declared as a @Bean:

@Bean
public PublishSubscribeChannel outputChannel() {
    return MessageChannels.publishSubscribe()
        .interceptor(new WireTap(loggerChannel()))
        .get();
}

The XML definition declares bean for the <int:wire-tap> via a Parser logic.

With Java configuration we don't have so much choice, unless @Bean for the target class if we would like to have it as a bean.

From other side the Java DSL has .wireTap() EIP-method. So, you don't need to declare all those beans. E.g. from our test-cases:

@Bean
public IntegrationFlow wireTapFlow5() {
    return f -> f
            .wireTap(sf -> sf
                    .<String, String>transform(String::toUpperCase)
                    .channel(c -> c.queue("wireTapSubflowResult")))
            .channel("nullChannel");
}

As you see we don't have any extra @Bean there and even we don't need the extra channel for the WireTap.

Let me know how more simple would you like to see it!