@ConditionalOnProperty annotation not working in spring boot project

Question

I want to conditionally create a spring bean. I figured @ConditionalOnProperty would serve that purpose. I used it in my service class but I do not see the bean being created.

Here is my bean that I want to be conditionally created

@Service
@ConditionalOnProperty(value = "polling.enabled", havingValue = "true")
public class MessageQueueService {

@Scheduled(fixedDelay = INTERVAL_MS)
    public void execute() {
     //sysout
    }
}

couple of thing to note.

-- our service loads properties directly from consul(due to legacy reasons) and not through spring environment

-- I hacked RestTemplate bean (below) to add custom propertyResource into environment. I did not know how to do it without creating another PropertySource bean instance.

@Configuration
public class AppConfig {

@Autowired
ConfigurableEnvironment env;

@Bean(name = "consulProps")
 public Properties properties() {
     Properties consulProperties = new ConsulDriver(env.getConsulUrl()).loadProperties();
    return properties;
 }

@Bean
@Autowired
public RestTemplate restTemplate(@Qualifier(consulProps) Properties props) {
    MutablePropertySources sources = env.getPropertySources();
    sources.addFirst(pollingEnabled(props));
    return new RestTemplate();
    }

private MapPropertySource pollingEnabled(Properties props) {
     String enabled = props.getProperty("polling.enabled"); // line 25
     Map<String, Object> map = new HashMap<>();
     if (StringUtils.isNotBlank(enabled)) {
           map.put("polling.enabled", enabled);
     }
     else {
          map.put("polling.enabled", "false");
     }
       return new MapPropertySource("polling", map);
    }

    @Bean
    public static PropertySourcesPlaceholderConfigurer propertyConfigIn() {
        return new PropertySourcesPlaceholderConfigurer();
    }
}

when I run the service, it starts up. I have set up polling.enabled is true in consul. while debugging, I confirmed the value is set correctly in line 25. However, the bean is NOT created. if I comment-out the @ConditionalOnProperty from the class, bean is created and the scheduled Method is called.

Any help to fix this is highly appreciated!! Thanks in advance

Answer 1

This did the work for me (Kotlin, but Java works exactly the same)

@Configuration
class ConditionalBeanConfig {

@Bean
@ConditionalOnProperty(name=["modbus.modbushelper"], havingValue="simulate")
fun conditionalModBusHelper(): ModBusApi {
   return  ModBusSimulatorImpl()
}

@Bean
@ConditionalOnProperty(name=["modbus.modbushelper"],     
havingValue="normal",matchIfMissing = true)
fun conditionalModBus(): ModBusApi {
   var modBusImpl:ModBusApi =  ModBusHelperImpl(Helper())
    return modBusImpl
}

}

interface ModBusApi {

    fun getModbusRegisterValue(startingAddress: Int, quantity: Int): String?

    fun setModbusSingleRegisterValue(startingAddress: Int, value: Int)

}  

class ModBusSimulatorImpl : ModBusApi {

 override fun getModbusRegisterValue(startingAddress: Int, quantity: Int): String? 

   ...

override fun setModbusSingleRegisterValue(startingAddress: Int, value: Int){
  
....

in combi with application.properties:

#simulate, normal
modbus.modbushelper=simulate

Make sure, you have, like always, your packaging in good health:

-Application starts with rootpackage.App

-All your objects/modules start with rootpackage.....

Spring CDI @ComponentScan is is very picky on that, and follows security Java conventions. If you dont, you can experience wide variety of CDI problems.