Example of @Requires(configuration=String)?

[jchambers]

Hello!

I've successfully used @Requires in a number of real-world use cases, but I'm a little fuzzy on using @Requires(configuration = String) and am hoping for a little help.

The docs say:

Expresses the configurations that should be present for the bean or configuration to load.

…but I'm not exactly sure what "configurations" means in this context.

I have a stanza like this in my application.yml file:

ejectorSeat:
  enabled: true

…and then:

@Context
@Requires(configuration = "ejectorSeat")
public class EjectorSeatSubsystem {
  // ...
}

…but that doesn't do quite what I'd expect; the requirement fails and the EjectorSeatSubsystem never gets instantiated. Is the configuration in this case supposed to be the FQCN of a class annotated with @ConfigurationProperties? That's not my read since other @Requires properties that refer to classes do, indeed, take a Class as an argument. If that's not it, what am I missing?

Thanks kindly!

[alvarosanchez]

Requiring a configuration refers to a bean configuration.

What you need is the following:

@Context
@Requires(property = "ejectorSeat.enabled", value = "true")
public class EjectorSeatSubsystem {
  // ...
}

[jchambers]

Ah—thank you. I had missed the whole concept of a bean configuration, and that was, indeed, the missing piece!