Support disabling messaging annotations processing

[mjd507]

By adding spring.integration.annotations.enable=false into the environment property or application.properties.

When disabled, the following post processors are not registered in the application context:

• MessagingAnnotationPostProcessor
• MessagingAnnotationBeanPostProcessor

[artembilan]

Please, don't touch GatewayProxyInstantiationPostProcessor and IntegrationComponentScanRegistrar.
They are for components scanning, for those which represents some entries on classpath.

Their purpose similar to the @ComponentScan in Spring Framework.

What we are trying to prevent here is annotations on methods in beans.
So, our goal would be similar to opting-in into something like @EnableMvc, but that does not mean that when we don't opt-in, the @ComponentScan should not work, too.

I agree that something like @EnableIntegrationMethodAnnotations would sound better for you to not look into the IntegrationComponentScanRegistrar, but I don't think we need to go such a fine-grain naming while we can just document this new property and future annotation properly.

Please, make a respective change and we will come back to you shortly for the further review.

Thanks

[artembilan]

Please, consider to mention this property in the respective annotations chapter and in the what’s new one, too.

thanks

[mjd507]

The scope is now much more precise and focused, thanks for the feedback.

[artembilan]

LGTM!
Will merge in the morning from laptop.

Thank you!