src/main/java/net/hostsharing/hsadminng/hs/hosting/asset/HsHostingAssetController.java

@@ -73,6 +73,7 @@ public class HsHostingAssetController implements HsHostingAssetsApi {
         final var entity = mapper.map(body, HsHostingAssetEntity.class, RESOURCE_TO_ENTITY_POSTMAPPER);
 
         final var mapped = new HsHostingAssetEntityProcessor(entity)
+                .preprocessEntity()
                 .validateEntity()
                 .prepareForSave()
                 .saveUsing(assetRepo::save)
@@ -133,6 +134,7 @@ public class HsHostingAssetController implements HsHostingAssetsApi {
         new HsHostingAssetEntityPatcher(em, entity).apply(body);
 
         final var mapped = new HsHostingAssetEntityProcessor(entity)
+                .preprocessEntity()
                 .validateEntity()
                 .prepareForSave()
                 .saveUsing(assetRepo::save)

src/main/java/net/hostsharing/hsadminng/hs/hosting/asset/validators/HsDomainDnsSetupHostingAssetValidator.java

@@ -9,6 +9,7 @@ import java.util.List;
 import java.util.regex.Pattern;
 
 import static java.util.Arrays.stream;
+import static java.util.Optional.ofNullable;
 import static net.hostsharing.hsadminng.hs.validation.ArrayProperty.arrayOf;
 import static net.hostsharing.hsadminng.hs.validation.BooleanProperty.booleanProperty;
 import static net.hostsharing.hsadminng.hs.validation.IntegerProperty.integerProperty;
@@ -50,7 +51,7 @@ class HsDomainDnsSetupHostingAssetValidator extends HsHostingAssetEntityValidato
                 booleanProperty("auto-WILDCARD-MX-RR").withDefault(true),
                 booleanProperty("auto-WILDCARD-A-RR").withDefault(true),
                 booleanProperty("auto-WILDCARD-AAAA-RR").withDefault(true),
-                booleanProperty("auto-WILDCARD-DKIM-RR").withDefault(true), // TODO.spec: @Peter
+                booleanProperty("auto-WILDCARD-DKIM-RR").withDefault(true), // TODO.spec: check, if that really works
                 booleanProperty("auto-WILDCARD-SPF-RR").withDefault(true),
                 arrayOf(
                         stringProperty("user-RR").matchesRegEx(RR_REGEX_TTL_IN, RR_REGEX_IN_TTL).required()
@@ -59,10 +60,17 @@ class HsDomainDnsSetupHostingAssetValidator extends HsHostingAssetEntityValidato
 
     @Override
     protected Pattern identifierPattern(final HsHostingAssetEntity assetEntity) {
-        // FIXME: should be auto-initialized
         return  Pattern.compile("^" + assetEntity.getParentAsset().getIdentifier() + "$");
     }
 
+    @Override
+    public void preprocessEntity(final HsHostingAssetEntity entity) {
+        super.preprocessEntity(entity);
+        if (entity.getIdentifier() == null) {
+            ofNullable(entity.getParentAsset()).ifPresent(pa -> entity.setIdentifier(pa.getIdentifier()));
+        }
+    }
+
     @Override
     @SneakyThrows
     public List<String> validateContext(final HsHostingAssetEntity assetEntity) {
@@ -80,6 +88,7 @@ class HsDomainDnsSetupHostingAssetValidator extends HsHostingAssetEntityValidato
     }
 
     String toZonefileString(final HsHostingAssetEntity assetEntity) {
+        // TODO.spec: we need to expand the templates (auto-...) in the same way as in Saltstack
         return """
               $ORIGIN {domain}.
               $TTL {ttl}

src/main/java/net/hostsharing/hsadminng/hs/hosting/asset/validators/HsHostingAssetEntityProcessor.java

@@ -14,6 +14,7 @@ import java.util.function.Function;
 public class HsHostingAssetEntityProcessor {
 
     private final HsEntityValidator<HsHostingAssetEntity> validator;
+    private String expectedStep = "preprocessEntity";
     private HsHostingAssetEntity entity;
     private HsHostingAssetResource resource;
 
@@ -22,8 +23,16 @@ public class HsHostingAssetEntityProcessor {
         this.validator = HsHostingAssetEntityValidatorRegistry.forType(entity.getType());
     }
 
+    /// initial step allowing to set default values before any validations
+    public HsHostingAssetEntityProcessor preprocessEntity() {
+        step("preprocessEntity", "validateEntity");
+        validator.preprocessEntity(entity);
+        return this;
+    }
+
     /// validates the entity itself including its properties
     public HsHostingAssetEntityProcessor validateEntity() {
+        step("validateEntity", "prepareForSave");
         MultiValidationException.throwIfNotEmpty(validator.validateEntity(entity));
         return this;
     }
@@ -31,17 +40,20 @@ public class HsHostingAssetEntityProcessor {
     /// hashing passwords etc.
     @SuppressWarnings("unchecked")
     public  HsHostingAssetEntityProcessor prepareForSave() {
+        step("prepareForSave", "saveUsing");
         validator.prepareProperties(entity);
         return this;
     }
 
     public HsHostingAssetEntityProcessor saveUsing(final Function<HsHostingAssetEntity, HsHostingAssetEntity> saveFunction) {
+        step("saveUsing", "validateContext");
         entity = saveFunction.apply(entity);
         return this;
     }
 
     /// validates the entity within it's parent and child hierarchy (e.g. totals validators and other limits)
     public HsHostingAssetEntityProcessor validateContext() {
+        step("validateContext", "mapUsing");
         MultiValidationException.throwIfNotEmpty(validator.validateContext(entity));
         return this;
     }
@@ -49,6 +61,7 @@ public class HsHostingAssetEntityProcessor {
     /// maps entity to JSON resource representation
     public HsHostingAssetEntityProcessor mapUsing(
             final Function<HsHostingAssetEntity, HsHostingAssetResource> mapFunction) {
+        step("mapUsing", "revampProperties");
         resource = mapFunction.apply(entity);
         return this;
     }
@@ -56,8 +69,18 @@ public class HsHostingAssetEntityProcessor {
     /// removes write-only-properties and ads computed-properties
     @SuppressWarnings("unchecked")
     public HsHostingAssetResource revampProperties() {
+        step("revampProperties", null);
         final var revampedProps = validator.revampProperties(entity, (Map<String, Object>) resource.getConfig());
         resource.setConfig(revampedProps);
         return resource;
     }
+
+    // Makes sure that the steps are called in the correct order.
+    // Could also be implemented using an interface per method, but that seems exaggerated.
+    private void step(final String current, final String next) {
+        if (!expectedStep.equals(current)) {
+            throw new IllegalStateException("expected " + expectedStep + " but got " + current);
+        }
+        expectedStep = next;
+    }
 }

src/main/java/net/hostsharing/hsadminng/hs/validation/HsEntityValidator.java

@@ -49,6 +49,13 @@ public abstract class HsEntityValidator<E extends PropertiesProvider> {
                 .collect(Collectors.toMap(p -> p.get("propertyName").toString(), p -> p));
     }
 
+    /**
+        Gets called before any validations take place.
+        Allows to initialize fields and properties to default values.
+     */
+    public void preprocessEntity(final E entity) {
+    }
+
     protected ArrayList<String> validateProperties(final PropertiesProvider propsProvider) {
         final var result = new ArrayList<String>();
 

src/test/java/net/hostsharing/hsadminng/hs/hosting/asset/validators/HsDomainDnsSetupHostingAssetValidatorUnitTest.java

@@ -43,6 +43,19 @@ class HsDomainDnsSetupHostingAssetValidatorUnitTest {
                 ));
     }
 
+    @Test
+    void preprocessesTakesIdentifierFromParent() {
+        // given
+        final var givenEntity = validEntityBuilder().build();
+        final var validator = HsHostingAssetEntityValidatorRegistry.forType(givenEntity.getType());
+
+        // when
+        validator.preprocessEntity(givenEntity);
+
+        // then
+        assertThat(givenEntity.getIdentifier()).isEqualTo(givenEntity.getParentAsset().getIdentifier());
+    }
+
     @Test
     void rejectsInvalidIdentifier() {
         // given