State-Stored Aggregate: AggregateIdentifier has to be String

Hi everyone,

we use state-based aggregates in our application.

We encountered that we have to use String for the aggregate identifier. Otherwise an exception occurs while sending a command to the aggregate by annotating the id field with @TargetAggregateIdentifier. In this example I tried to use a java.util.UUID:

java.lang.IllegalStateException: Failed to execute CommandLineRunner
	at org.springframework.boot.SpringApplication.callRunner(SpringApplication.java:816) ~[spring-boot-2.1.4.RELEASE.jar:2.1.4.RELEASE]
	at org.springframework.boot.SpringApplication.callRunners(SpringApplication.java:797) ~[spring-boot-2.1.4.RELEASE.jar:2.1.4.RELEASE]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:324) ~[spring-boot-2.1.4.RELEASE.jar:2.1.4.RELEASE]
	at org.springframework.boot.builder.SpringApplicationBuilder.run(SpringApplicationBuilder.java:139) ~[spring-boot-2.1.4.RELEASE.jar:2.1.4.RELEASE]
	at de.libutzki.axon.axonhierarchical.AxonHierarchicalApplication.main(AxonHierarchicalApplication.java:20) ~[classes/:na]
Caused by: java.lang.IllegalArgumentException: Provided id of the wrong type for class de.libutzki.axon.axonhierarchical.module2.entity.Module2Aggregate. Expected: class java.util.UUID, got class java.lang.String
	at org.hibernate.internal.SessionImpl.find(SessionImpl.java:3503) ~[hibernate-core-5.3.9.Final.jar:5.3.9.Final]
	at org.hibernate.internal.SessionImpl.find(SessionImpl.java:3456) ~[hibernate-core-5.3.9.Final.jar:5.3.9.Final]
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:na]
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:na]
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:na]
	at java.base/java.lang.reflect.Method.invoke(Method.java:566) ~[na:na]
	at org.springframework.orm.jpa.SharedEntityManagerCreator$SharedEntityManagerInvocationHandler.invoke(SharedEntityManagerCreator.java:308) ~[spring-orm-5.1.6.RELEASE.jar:5.1.6.RELEASE]
	at com.sun.proxy.$Proxy71.find(Unknown Source) ~[na:na]
	at org.axonframework.modelling.command.GenericJpaRepository.doLoadWithLock(GenericJpaRepository.java:110) ~[axon-modelling-4.1.1.jar:4.1.1]
	at org.axonframework.modelling.command.GenericJpaRepository.doLoadWithLock(GenericJpaRepository.java:53) ~[axon-modelling-4.1.1.jar:4.1.1]
	at org.axonframework.modelling.command.LockingRepository.doLoad(LockingRepository.java:118) ~[axon-modelling-4.1.1.jar:4.1.1]
	at org.axonframework.modelling.command.LockingRepository.doLoad(LockingRepository.java:52) ~[axon-modelling-4.1.1.jar:4.1.1]
	at org.axonframework.modelling.command.AbstractRepository.lambda$load$4(AbstractRepository.java:122) ~[axon-modelling-4.1.1.jar:4.1.1]
	at java.base/java.util.HashMap.computeIfAbsent(HashMap.java:1133) ~[na:na]
	at org.axonframework.modelling.command.AbstractRepository.load(AbstractRepository.java:121) ~[axon-modelling-4.1.1.jar:4.1.1]
	at org.axonframework.modelling.command.AggregateAnnotationCommandHandler$AggregateCommandHandler.handle(AggregateAnnotationCommandHandler.java:349) ~[axon-modelling-4.1.1.jar:4.1.1]
	at org.axonframework.modelling.command.AggregateAnnotationCommandHandler$AggregateCommandHandler.handle(AggregateAnnotationCommandHandler.java:337) ~[axon-modelling-4.1.1.jar:4.1.1]
	at org.axonframework.modelling.command.AggregateAnnotationCommandHandler.handle(AggregateAnnotationCommandHandler.java:125) ~[axon-modelling-4.1.1.jar:4.1.1]
	at org.axonframework.modelling.command.AggregateAnnotationCommandHandler.handle(AggregateAnnotationCommandHandler.java:44) ~[axon-modelling-4.1.1.jar:4.1.1]
	at org.axonframework.messaging.DefaultInterceptorChain.proceed(DefaultInterceptorChain.java:57) ~[axon-messaging-4.1.1.jar:4.1.1]
	at org.axonframework.messaging.interceptors.CorrelationDataInterceptor.handle(CorrelationDataInterceptor.java:65) ~[axon-messaging-4.1.1.jar:4.1.1]
	at org.axonframework.messaging.DefaultInterceptorChain.proceed(DefaultInterceptorChain.java:55) ~[axon-messaging-4.1.1.jar:4.1.1]
	at org.axonframework.messaging.unitofwork.DefaultUnitOfWork.executeWithResult(DefaultUnitOfWork.java:74) ~[axon-messaging-4.1.1.jar:4.1.1]
	at org.axonframework.commandhandling.SimpleCommandBus.handle(SimpleCommandBus.java:176) ~[axon-messaging-4.1.1.jar:4.1.1]
	at org.axonframework.commandhandling.SimpleCommandBus.doDispatch(SimpleCommandBus.java:141) ~[axon-messaging-4.1.1.jar:4.1.1]
	at org.axonframework.commandhandling.SimpleCommandBus.dispatch(SimpleCommandBus.java:110) ~[axon-messaging-4.1.1.jar:4.1.1]
	at org.axonframework.commandhandling.gateway.AbstractCommandGateway.send(AbstractCommandGateway.java:75) ~[axon-messaging-4.1.1.jar:4.1.1]
	at org.axonframework.commandhandling.gateway.DefaultCommandGateway.send(DefaultCommandGateway.java:73) ~[axon-messaging-4.1.1.jar:4.1.1]
	at org.axonframework.commandhandling.gateway.DefaultCommandGateway.sendAndWait(DefaultCommandGateway.java:90) ~[axon-messaging-4.1.1.jar:4.1.1]
	at de.libutzki.axon.axonhierarchical.module2.Module2Runner.run(Module2Runner.java:42) ~[classes/:na]
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:na]
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:na]
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:na]
	at java.base/java.lang.reflect.Method.invoke(Method.java:566) ~[na:na]
	at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:343) ~[spring-aop-5.1.6.RELEASE.jar:5.1.6.RELEASE]
	at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:198) ~[spring-aop-5.1.6.RELEASE.jar:5.1.6.RELEASE]
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:163) ~[spring-aop-5.1.6.RELEASE.jar:5.1.6.RELEASE]
	at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:294) ~[spring-tx-5.1.6.RELEASE.jar:5.1.6.RELEASE]
	at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:98) ~[spring-tx-5.1.6.RELEASE.jar:5.1.6.RELEASE]
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.1.6.RELEASE.jar:5.1.6.RELEASE]
	at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:212) ~[spring-aop-5.1.6.RELEASE.jar:5.1.6.RELEASE]
	at com.sun.proxy.$Proxy85.run(Unknown Source) ~[na:na]
	at org.springframework.boot.SpringApplication.callRunner(SpringApplication.java:813) ~[spring-boot-2.1.4.RELEASE.jar:2.1.4.RELEASE]
	... 4 common frames omitted
Caused by: org.hibernate.TypeMismatchException: Provided id of the wrong type for class de.libutzki.axon.axonhierarchical.module2.entity.Module2Aggregate. Expected: class java.util.UUID, got class java.lang.String
	at org.hibernate.event.internal.DefaultLoadEventListener.checkIdClass(DefaultLoadEventListener.java:169) ~[hibernate-core-5.3.9.Final.jar:5.3.9.Final]
	at org.hibernate.event.internal.DefaultLoadEventListener.onLoad(DefaultLoadEventListener.java:89) ~[hibernate-core-5.3.9.Final.jar:5.3.9.Final]
	at org.hibernate.internal.SessionImpl.fireLoad(SessionImpl.java:1256) ~[hibernate-core-5.3.9.Final.jar:5.3.9.Final]
	at org.hibernate.internal.SessionImpl.access$1900(SessionImpl.java:207) ~[hibernate-core-5.3.9.Final.jar:5.3.9.Final]
	at org.hibernate.internal.SessionImpl$IdentifierLoadAccessImpl.doLoad(SessionImpl.java:2866) ~[hibernate-core-5.3.9.Final.jar:5.3.9.Final]
	at org.hibernate.internal.SessionImpl$IdentifierLoadAccessImpl.load(SessionImpl.java:2847) ~[hibernate-core-5.3.9.Final.jar:5.3.9.Final]
	at org.hibernate.internal.SessionImpl.find(SessionImpl.java:3482) ~[hibernate-core-5.3.9.Final.jar:5.3.9.Final]
	... 46 common frames omitted

While researching I stumbled upon org.axonframework.modelling.command.GenericJpaRepository.Builder.identifierConverter(Function<String, ?>)

But there are two major problems:

1. I use Spring Boot and the GenericJpaRepositories are built in org.axonframework.spring.config.SpringAxonAutoConfigurer.registerAggregateBeanDefinitions(Configurer, BeanDefinitionRegistry) which cannot be customized easily. I have to override (nearly) the whole class to adjust the behaviour. Anyway, by doing this and setting .identifierConverter(UUID::fromString) the command can be handled.
2. The solution only works if I use a type which’s toString() result can be reverted back to the type (like UUID.fromString(String) does). In practice I don’t want to use a UUID as id but a value object like CustomerId which wraps a UUID. Having this I do not see any chance to annotate it with @AggregateIdentifier and to use it in a state-based aggregate.

As stated in #484 you also prefer the usage of value objects, but unfortunately I do not find a way to do this. Maybe it’s a lack of documentation, but I fear it’s a missing feature. That’s the reason why I decided to create this issue.

[nils-christian]

Hi,

We tested some possible solutions in the meantime. The suggested idea of @smcvb works well (custom JPA repository with suitable identifier converter), but this would mean a custom repository for each state stored aggregate. Therefore we decided to use another approach. We used a more generic identifier converter, which would use the Spring conversion mechanism, and added it to the registerAggregateBeanDefinitions in the configurer.

final Class<?> aggregateIdentifierType = Stream.of( aggregateType.getDeclaredFields( ) )
		.filter( field -> field.isAnnotationPresent( AggregateIdentifier.class ) )
		.map( field -> field.getType( ) )
		.findFirst( )
		.orElseThrow( ( ) -> new IllegalStateException( "The aggregate '" + aggregate + "' does not have an identifier." ) );

aggregateConf.configureRepository(
		c -> GenericJpaRepository.builder( aggregateType )
				.identifierConverter( string -> {
					if ( aggregateType == String.class ) {
						return string;
					} else {
						try {
							final ConversionService conversionService = beanFactory.getBean( ConversionService.class );
							return conversionService.convert( string, aggregateIdentifierType );
						} catch ( final NoSuchBeanDefinitionException ex ) {
							throw new IllegalStateException( "Unable to convert String to aggregate identifier of type '" + aggregateIdentifierType.getName( ) + "'. A conversion service is missing." );
						}
					}
				} )

So the basic idea is to find the type of the aggregate identifier and - unless it is already a String - convert it via the Spring conversion service. One would then have a suitable converter for each identifier.

@Named
final class MyIdConverter implements Converter<String, MyId> {

	...

	@Override
	public MyId convert( final String source ) {
		return MyId.fromString( source );
	}

}

In case of UUID identifiers one would only need the Spring conversion service, as it is already equipped with a String to UUID converter.

The only disadvantage of this approach is that we have to override the whole class to modify the private method. Maybe it would be possible to improve the code in this regard?

Best regards

Nils

[smcvb]

Reopening seems reasonable to me, so let’s do that 😃