Reading custom property type from JPA @ManyToOne.targetEntity

Hello,

let’s suppose I have the following interface:

interface CategoryEntityDefinition {
}

with the following implementation:

@Entity
class CategoryEntity implements CategoryEntityDefinition {

     @Id    
     private long id;
}

and then I have the following JPA entity:

@Entity
class ProductEntity  {

    @NotNull
    @ManyToOne(fetch = FetchType.LAZY, targetEntity = CategoryEntity.class)
    @JoinColumn(name = "category_id", nullable = false, referencedColumnName = "id", foreignKey = @ForeignKey(name = (("fk_"+ ProductEntity.NAME)+"_category")))
    @JsonProperty(required = true)
    private CategoryEntityDefinition category;
}

Now i try to diff two objects of type ProductEntity and I get the following exception:

2017-11-17 16:28:47,245 org.apache.catalina.core.ContainerBase.[Tomcat].[localhost].[/storefront].[dispatcherServlet] [https-jsse-nio-127.0.0.1-8112-exec-4] ERROR: Servlet.service() for servlet [dispatcherServlet] in context with path [/storefront] threw exception [Request processing failed; nested exception is JaversException ENTITY_WITHOUT_ID: Class 'com.nemesis.platform.core.definition.catalog.CategoryEntityDefinition' mapped as Entity has no Id property. Use @Id annotation to mark unique and not-null Entity identifier] with root cause
JaversException ENTITY_WITHOUT_ID: Class 'com.nemesis.platform.core.definition.catalog.CategoryEntityDefinition' mapped as Entity has no Id property. Use @Id annotation to mark unique and not-null Entity identifier
	at org.javers.core.metamodel.type.EntityTypeFactory.findDefaultIdProperty(EntityTypeFactory.java:43)
	at org.javers.core.metamodel.type.EntityTypeFactory.createEntity(EntityTypeFactory.java:25)
	at org.javers.core.metamodel.type.TypeFactory.create(TypeFactory.java:42)
	at org.javers.core.metamodel.type.TypeFactory.inferFromAnnotations(TypeFactory.java:129)
	at org.javers.core.metamodel.type.TypeFactory.infer(TypeFactory.java:70)
	at org.javers.core.metamodel.type.TypeMapperState.infer(TypeMapperState.java:149)
	at org.javers.core.metamodel.type.TypeMapperState.lambda$getJaversType$0(TypeMapperState.java:87)
	at org.javers.core.metamodel.type.TypeMapperState.computeIfAbsent(TypeMapperState.java:111)
	at org.javers.core.metamodel.type.TypeMapperState.getJaversType(TypeMapperState.java:87)
	at org.javers.core.metamodel.type.TypeMapper.getJaversType(TypeMapper.java:124)
	at org.javers.core.metamodel.type.ManagedClassFactory.lambda$null$3(ManagedClassFactory.java:50)
	at org.javers.core.metamodel.type.JaversProperty.getType(JaversProperty.java:23)
	at org.javers.core.graph.ObjectGraphBuilder.lambda$getSingleReferencesWithManagedTypes$0(ObjectGraphBuilder.java:105)
	at java.util.stream.ReferencePipeline$2$1.accept(ReferencePipeline.java:174)
	at java.util.ArrayList$ArrayListSpliterator.forEachRemaining(ArrayList.java:1380)
	at java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:481)
	at java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:471)
	at java.util.stream.ReduceOps$ReduceOp.evaluateSequential(ReduceOps.java:708)
	at java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
	at java.util.stream.ReferencePipeline.collect(ReferencePipeline.java:499)
	at org.javers.common.collections.Lists.positiveFilter(Lists.java:55)
	at org.javers.core.metamodel.type.ManagedClass.getManagedProperties(ManagedClass.java:63)
	at org.javers.core.metamodel.type.ManagedType.getProperties(ManagedType.java:49)
	at org.javers.core.graph.ObjectGraphBuilder.getSingleReferencesWithManagedTypes(ObjectGraphBuilder.java:105)
	at org.javers.core.graph.ObjectGraphBuilder.buildSingleEdges(ObjectGraphBuilder.java:75)
	at org.javers.core.graph.ObjectGraphBuilder.buildEdges(ObjectGraphBuilder.java:70)
	at org.javers.core.graph.ObjectGraphBuilder.buildGraphFromCdo(ObjectGraphBuilder.java:58)
	at org.javers.core.graph.ObjectGraphBuilder.buildGraph(ObjectGraphBuilder.java:47)
	at org.javers.core.graph.LiveGraphFactory.createLiveGraph(LiveGraphFactory.java:39)
	at org.javers.core.diff.DiffFactory.buildGraph(DiffFactory.java:98)
	at org.javers.core.diff.DiffFactory.compare(DiffFactory.java:53)
	at org.javers.core.JaversCore.compare(JaversCore.java:134)
	at org.javers.spring.jpa.JaversTransactionalDecorator.compare(JaversTransactionalDecorator.java:94)
	at org.javers.spring.jpa.JaversTransactionalDecorator$$FastClassBySpringCGLIB$$acb40bd0.invoke(<generated>)
	at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:204)
	at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:669)
	at org.javers.spring.jpa.JaversTransactionalDecorator$$EnhancerBySpringCGLIB$$71cf87d.compare(<generated>)
	at com.nemesis.platform.module.restservices.storefront.controller.RestDiffController.synchronize(RestDiffController.java:69)

This seems to be because here:

https://github.com/javers/javers/blob/master/javers-core/src/main/java/org/javers/core/metamodel/type/ManagedClassFactory.java#L50

You get the generic type of the attribute, while in JPA my case is perfectly valid and what you should do is get the targetEntity attribute of the @ManyToOne annotation on the attribute.

[tinesoft]

@bartoszwalacik I’m interested to provide a PR for this one, if still available…

[bartoszwalacik]

Consider contributing a PR. We don’t want more annotation logic in JaVares so this issue could be implemented by adding a possibility to register custom PropertyTypeResolver (as you suggested).