improved error messages if entity not found

README.md

@@ -550,12 +550,37 @@ Dependency versions can be automatically upgraded to the latest available versio
 gw useLatestVersions
 ```
 
-Afterwards, `gw check` is automatically started.
+Afterward, `gw check` is automatically started.
 Please only commit+push to master if the check run shows no errors.
 
 More infos, e.g. on blacklists see on the [project's website](https://github.com/patrikerdes/gradle-use-latest-versions-plugin).
 
 
+## Biggest Flaws in our Architecture
+
+### The RBAC System is too Complicated
+
+Now, where we have a better experience with what we really need from the RBAC system, we have learned
+that and creates too many (grant- and role-) rows and too even tables which could be avoided completely.
+
+The basic idea is always to always have a fixed set of ordered role-types which apply for all DB-tables under RBAC,
+e.g. OWNER>ADMIN>AGENT\[>PROXY?\]>TENENT>REFERRER.
+Grants between these for the same DB-row would be implicit by order comparision.
+This way we would get rid of all explicit grants within the same DB-row
+and would not need the `rbac.role` table anymore.
+We would also reduce the depth of the expensive recursive CTE-query.
+
+This has to be explored further.
+For now, we just keep it in mind and  
+
+### The Mapper is Error-Prone
+
+Where `org.modelmapper.ModelMapper` reduces bloat-code a lot and has some nice features about recursive data-structure mappings,
+it often causes strange errors which are hard to fix.
+E.g. the uuid of the target main object is often taken from an uuid of a sub-subject.
+(For now, use `StrictMapper` to avoid this, for the case it happens.)
+
+
 ## How To ...
 
 ### How to Configure .pgpass for the Default PostgreSQL Database?

src/main/java/net/hostsharing/hsadminng/errors/DisplayAs.java

@@ -11,13 +11,18 @@ import java.lang.annotation.Target;
 public @interface DisplayAs {
     class DisplayName {
         public static String of(final Class<?> clazz) {
-            final var displayNameAnnot = clazz.getAnnotation(DisplayAs.class);
+            final var displayNameAnnot = getDisplayNameAnnotation(clazz);
             return displayNameAnnot != null ? displayNameAnnot.value() : clazz.getSimpleName();
         }
 
         public static String of(@NotNull final Object instance) {
             return of(instance.getClass());
         }
+
+        private static DisplayAs getDisplayNameAnnotation(final Class<?> clazz) {
+                     final var annot =  clazz.getAnnotation(DisplayAs.class);
+                     return annot != null ? annot : getDisplayNameAnnotation(clazz.getSuperclass());
+        }
     }
 
     String value() default "";

src/main/java/net/hostsharing/hsadminng/hs/office/debitor/HsOfficeDebitorController.java

@@ -8,7 +8,7 @@ import net.hostsharing.hsadminng.hs.office.generated.api.v1.model.HsOfficeDebito
 import net.hostsharing.hsadminng.hs.office.relation.HsOfficeRelationRealEntity;
 import net.hostsharing.hsadminng.hs.office.relation.HsOfficeRelationRealRepository;
 import net.hostsharing.hsadminng.mapper.StandardMapper;
-import net.hostsharing.hsadminng.rbac.object.BaseEntity;
+import net.hostsharing.hsadminng.persistence.EntityExistsValidator;
 import org.apache.commons.lang3.Validate;
 import org.hibernate.Hibernate;
 import org.springframework.beans.factory.annotation.Autowired;
@@ -23,7 +23,6 @@ import jakarta.validation.ValidationException;
 import java.util.List;
 import java.util.UUID;
 
-import static net.hostsharing.hsadminng.errors.DisplayAs.DisplayName;
 import static net.hostsharing.hsadminng.hs.office.relation.HsOfficeRelationType.DEBITOR;
 
 @RestController
@@ -42,6 +41,9 @@ public class HsOfficeDebitorController implements HsOfficeDebitorsApi {
     @Autowired
     private HsOfficeRelationRealRepository relrealRepo;
 
+    @Autowired
+    private EntityExistsValidator entityValidator;
+
     @PersistenceContext
     private EntityManager em;
 
@@ -85,9 +87,9 @@ public class HsOfficeDebitorController implements HsOfficeDebitorsApi {
         if ( body.getDebitorRel() != null ) {
             body.getDebitorRel().setType(DEBITOR.name());
             final var debitorRel = mapper.map("debitorRel.", body.getDebitorRel(), HsOfficeRelationRealEntity.class);
-            validateEntityExists("debitorRel.anchorUuid", debitorRel.getAnchor());
+            entityValidator.validateEntityExists("debitorRel.anchorUuid", debitorRel.getAnchor());
-            validateEntityExists("debitorRel.holderUuid", debitorRel.getHolder());
+            entityValidator.validateEntityExists("debitorRel.holderUuid", debitorRel.getHolder());
-            validateEntityExists("debitorRel.contactUuid", debitorRel.getContact());
+            entityValidator.validateEntityExists("debitorRel.contactUuid", debitorRel.getContact());
             entityToSave.setDebitorRel(relrealRepo.save(debitorRel));
         } else {
             final var debitorRelOptional = relrealRepo.findByUuid(body.getDebitorRelUuid());
@@ -160,15 +162,4 @@ public class HsOfficeDebitorController implements HsOfficeDebitorsApi {
         final var mapped = mapper.map(saved, HsOfficeDebitorResource.class);
         return ResponseEntity.ok(mapped);
     }
-
-    // TODO.impl: extract this to some generally usable class?
-    private <T extends BaseEntity<T>> T validateEntityExists(final String property, final T entitySkeleton) {
-        final var foundEntity = em.find(entitySkeleton.getClass(), entitySkeleton.getUuid());
-        if ( foundEntity == null) {
-            throw new ValidationException("Unable to find " + DisplayName.of(entitySkeleton) + " by " + property + ": " + entitySkeleton.getUuid());
-        }
-
-        //noinspection unchecked
-        return (T) foundEntity;
-    }
 }

src/main/java/net/hostsharing/hsadminng/persistence/EntityExistsValidator.java

@@ -0,0 +1,41 @@
+package net.hostsharing.hsadminng.persistence;
+
+import lombok.experimental.UtilityClass;
+import net.hostsharing.hsadminng.errors.DisplayAs;
+import net.hostsharing.hsadminng.errors.DisplayAs.DisplayName;
+import net.hostsharing.hsadminng.rbac.object.BaseEntity;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.stereotype.Service;
+
+import jakarta.persistence.Entity;
+import jakarta.validation.ValidationException;
+
+@Service
+public class EntityExistsValidator {
+
+    @Autowired
+    private EntityManagerWrapper em;
+
+    public <T extends BaseEntity<T>> void validateEntityExists(final String property, final T entitySkeleton) {
+        final var foundEntity = em.find(entityClass(entitySkeleton), entitySkeleton.getUuid());
+        if ( foundEntity == null) {
+            throw new ValidationException("Unable to find " + DisplayName.of(entitySkeleton) + " by " + property + ": " + entitySkeleton.getUuid());
+        }
+    }
+
+    private static <T extends BaseEntity<T>> Class<?> entityClass(final T entityOrProxy) {
+        final var entityClass = entityClass(entityOrProxy.getClass());
+        if (entityClass == null) {
+            throw new IllegalArgumentException("@Entity not found in superclass hierarchy of " + entityOrProxy.getClass());
+        }
+        return entityClass;
+    }
+
+    private static Class<?> entityClass(final Class<?> entityOrProxyClass) {
+        return entityOrProxyClass.isAnnotationPresent(Entity.class)
+                ? entityOrProxyClass
+                : entityOrProxyClass.getSuperclass() == null
+                ? null
+                : entityClass(entityOrProxyClass.getSuperclass());
+    }
+}

src/test/java/net/hostsharing/hsadminng/hs/office/debitor/HsOfficeDebitorControllerAcceptanceTest.java

@@ -405,7 +405,7 @@ class HsOfficeDebitorControllerAcceptanceTest extends ContextBasedTestWithCleanu
                     .post("http://localhost/api/hs/office/debitors")
                 .then().log().all().assertThat()
                     .statusCode(400)
-                    .body("message", is("ERROR: [400] Unable to find RealContact by debitorRel.contact.uuid: 00000000-0000-0000-0000-000000000000"));
+                    .body("message", is("ERROR: [400] Unable to find RealContact by debitorRel.contactUuid: 00000000-0000-0000-0000-000000000000"));
             // @formatter:on
         }
 
@@ -433,7 +433,7 @@ class HsOfficeDebitorControllerAcceptanceTest extends ContextBasedTestWithCleanu
                     .post("http://localhost/api/hs/office/debitors")
                 .then().log().all().assertThat()
                     .statusCode(400)
-                    .body("message", is("ERROR: [400] Unable to find RealRelation by debitorRel.uuid: 00000000-0000-0000-0000-000000000000"));
+                    .body("message", is("ERROR: [400] Unable to find RealRelation by debitorRelUuid: 00000000-0000-0000-0000-000000000000"));
                 // @formatter:on
         }
     }