Spring bean depends on a conditional bean

Question

I want a spring bean to be instanciated after another bean. So I simply use the @DependsOn annotation.

The thing is : this other bean is a conditional bean wearing the @ConditionalOnProperty(name = "some.property", havingValue = "true") annotation. So when the property is false then the bean is not instanciated (and that's what we want), and the @DependsOn obviously fails. The goal here is : create the second bean anyway, but create it after the first one if it was created.

Is there a way to do that without removing the @ConditionalOnProperty ? And without playing with the @Order annotation ?

Thank you for your help

Answer 1

How about the following approach:

interface Something {}

public class FirstBean implements Something {}

public class SecondBean implements Something{} // maybe empty implementation

Now the configuration goes like this:

@Configuration
public class MyConfiguration {

  @Bean(name = "hello")
  @ConditionalOnProperty(name = "some.property", havingValue = true) 
  public Something helloBean() {
     return new FirstBean();
  }

  @Bean(name = "hello")
  @ConditionalOnProperty(name = "some.property", havingValue = false) 
  public Something secondBean() {
     return new SecondBean();
  }

  @Bean
  @DependsOn("hello")
  public MyDependantBean dependantBean() {
       return new MyDependantBean();
  }
}

The idea is to create the "Something" bean anyway (even if its an empty implementation), so that the dependant bean will depend on Something in any case.

I've not tried this myself, you know, spring is full of magic, but probably it worth a try:)

Answer 2

Instead of using @DependsOn you can use @AutoConfigureAfter()which will allow the second bean to be created even if the first bean was not created, but still keep the order.

@Configuration
public class FirstConfiguration {

  @Bean(name = "firstBean")
  @ConditionalOnProperty(name = "some.property", havingValue = true) 
  public FirstBean firstBean() {
     return new FirstBean();
  }
}

@Configuration
@AutoConfigureAfter(name = {"firstBean"})
public class SecondConfiguration {

  @Bean
  public SecondBean secondBean() {
       return new SecondBean();
  }
}