How to silently cancel bean creation?

Question

@Component
public class MyBean {

  @Autowired
  public MyBean(@Value("${optional:#{null}}") String optional) {
    if (optional == null) {
      // cancel bean creation?
    }
  }

}

How to silently cancel bean creation? I could throw a RuntimeException, but I don't want this cancellation to be considered as an error: the bean must just not be created, the application initialization must go on.

Answer 1

Here you can make use of @Conditional

Step 1- Implement Condition.matches so as to specify when should the bean be created or not.

public class SomeCondition implements Condition {
    @Override
    public boolean matches(ConditionContext context, AnnotatedTypeMetadata metadata) {
        return System.getProperty("optional") != null;
    }
}

The condition class is referred as direct class (not as spring bean) so it can't use the @Value property injection. See here for alternative

Step 2 - In the configuration class specify the above class as condition to decide the bean creation

@Configuration
public class SomeAppConfig {

    @Bean
    @Condition(SomeCondition.class)
    public MyBean myBean() {
      return new MyBean();
    }
}

P.S.: I have assumed that you use Java config.