Refactor domain models to records and move exceptions to sub-package

- Convert Event and Rsvp from mutable POJOs to Java records
- Move all 8 exception classes to application.service.exception sub-package
- Add ArchUnit rule enforcing domain models must be records

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

backend/src/main/java/de/fete/adapter/in/web/EventController.java

@@ -9,8 +9,8 @@ import de.fete.adapter.in.web.model.CreateRsvpResponse;
 import de.fete.adapter.in.web.model.GetAttendeesResponse;
 import de.fete.adapter.in.web.model.GetEventResponse;
 import de.fete.adapter.in.web.model.PatchEventRequest;
-import de.fete.application.service.EventNotFoundException;
+import de.fete.application.service.exception.EventNotFoundException;
-import de.fete.application.service.InvalidTimezoneException;
+import de.fete.application.service.exception.InvalidTimezoneException;
 import de.fete.domain.model.CreateEventCommand;
 import de.fete.domain.model.Event;
 import de.fete.domain.model.EventToken;
@@ -78,11 +78,11 @@ public class EventController implements EventsApi {
     Event event = createEventUseCase.createEvent(command);
 
     var response = new CreateEventResponse();
-    response.setEventToken(event.getEventToken().value());
+    response.setEventToken(event.eventToken().value());
-    response.setOrganizerToken(event.getOrganizerToken().value());
+    response.setOrganizerToken(event.organizerToken().value());
-    response.setTitle(event.getTitle());
+    response.setTitle(event.title());
-    response.setDateTime(event.getDateTime());
+    response.setDateTime(event.dateTime());
-    response.setTimezone(event.getTimezone().getId());
+    response.setTimezone(event.timezone().getId());
 
     return ResponseEntity.status(HttpStatus.CREATED).body(response);
   }
@@ -94,16 +94,16 @@ public class EventController implements EventsApi {
         .orElseThrow(() -> new EventNotFoundException(eventToken));
 
     var response = new GetEventResponse();
-    response.setEventToken(event.getEventToken().value());
+    response.setEventToken(event.eventToken().value());
-    response.setTitle(event.getTitle());
+    response.setTitle(event.title());
-    response.setDescription(event.getDescription());
+    response.setDescription(event.description());
-    response.setDateTime(event.getDateTime());
+    response.setDateTime(event.dateTime());
-    response.setTimezone(event.getTimezone().getId());
+    response.setTimezone(event.timezone().getId());
-    response.setLocation(event.getLocation());
+    response.setLocation(event.location());
     response.setAttendeeCount(
         (int) countAttendeesByEventUseCase.countByEvent(evtToken));
-    response.setCancelled(event.isCancelled());
+    response.setCancelled(event.cancelled());
-    response.setCancellationReason(event.getCancellationReason());
+    response.setCancellationReason(event.cancellationReason());
 
     return ResponseEntity.ok(response);
   }
@@ -145,8 +145,8 @@ public class EventController implements EventsApi {
     Rsvp rsvp = createRsvpUseCase.createRsvp(evtToken, createRsvpRequest.getName());
 
     var response = new CreateRsvpResponse();
-    response.setRsvpToken(rsvp.getRsvpToken().value());
+    response.setRsvpToken(rsvp.rsvpToken().value());
-    response.setName(rsvp.getName());
+    response.setName(rsvp.name());
 
     return ResponseEntity.status(HttpStatus.CREATED).body(response);
   }

backend/src/main/java/de/fete/adapter/in/web/GlobalExceptionHandler.java

@@ -1,13 +1,13 @@
 package de.fete.adapter.in.web;
 
-import de.fete.application.service.EventAlreadyCancelledException;
+import de.fete.application.service.exception.EventAlreadyCancelledException;
-import de.fete.application.service.EventCancelledException;
+import de.fete.application.service.exception.EventCancelledException;
-import de.fete.application.service.EventExpiredException;
+import de.fete.application.service.exception.EventExpiredException;
-import de.fete.application.service.EventNotFoundException;
+import de.fete.application.service.exception.EventNotFoundException;
-import de.fete.application.service.ExpiryDateBeforeEventException;
+import de.fete.application.service.exception.ExpiryDateBeforeEventException;
-import de.fete.application.service.ExpiryDateInPastException;
+import de.fete.application.service.exception.ExpiryDateInPastException;
-import de.fete.application.service.InvalidOrganizerTokenException;
+import de.fete.application.service.exception.InvalidOrganizerTokenException;
-import de.fete.application.service.InvalidTimezoneException;
+import de.fete.application.service.exception.InvalidTimezoneException;
 import java.net.URI;
 import java.util.List;
 import java.util.Map;

backend/src/main/java/de/fete/adapter/in/web/SpaController.java

@@ -86,11 +86,11 @@ public class SpaController {
 
   private Map<String, String> buildEventMeta(Event event, String baseUrl) {
     var tags = new LinkedHashMap<String, String>();
-    String title = truncateTitle(event.getTitle());
+    String title = truncateTitle(event.title());
     String description = formatDescription(event);
     tags.put("og:title", title);
     tags.put("og:description", description);
-    tags.put("og:url", baseUrl + "/events/" + event.getEventToken().value());
+    tags.put("og:url", baseUrl + "/events/" + event.eventToken().value());
     tags.put("og:type", "website");
     tags.put("og:site_name", GENERIC_TITLE);
     tags.put("og:image", baseUrl + "/og-image.png");
@@ -138,16 +138,16 @@ public class SpaController {
   }
 
   private String formatDescription(Event event) {
-    ZonedDateTime zoned = event.getDateTime().atZoneSameInstant(event.getTimezone());
+    ZonedDateTime zoned = event.dateTime().atZoneSameInstant(event.timezone());
     var sb = new StringBuilder();
     sb.append("📅 ").append(zoned.format(DATE_FORMAT));
 
-    if (event.getLocation() != null && !event.getLocation().isBlank()) {
+    if (event.location() != null && !event.location().isBlank()) {
-      sb.append(" · 📍 ").append(event.getLocation());
+      sb.append(" · 📍 ").append(event.location());
     }
 
-    if (event.getDescription() != null && !event.getDescription().isBlank()) {
+    if (event.description() != null && !event.description().isBlank()) {
-      sb.append(" — ").append(event.getDescription());
+      sb.append(" — ").append(event.description());
     }
 
     String result = sb.toString();

backend/src/main/java/de/fete/adapter/out/persistence/EventPersistenceAdapter.java

@@ -38,35 +38,34 @@ public class EventPersistenceAdapter implements EventRepository {
 
   private EventJpaEntity toEntity(Event event) {
     var entity = new EventJpaEntity();
-    entity.setId(event.getId());
+    entity.setId(event.id());
-    entity.setEventToken(event.getEventToken().value());
+    entity.setEventToken(event.eventToken().value());
-    entity.setOrganizerToken(event.getOrganizerToken().value());
+    entity.setOrganizerToken(event.organizerToken().value());
-    entity.setTitle(event.getTitle());
+    entity.setTitle(event.title());
-    entity.setDescription(event.getDescription());
+    entity.setDescription(event.description());
-    entity.setDateTime(event.getDateTime());
+    entity.setDateTime(event.dateTime());
-    entity.setTimezone(event.getTimezone().getId());
+    entity.setTimezone(event.timezone().getId());
-    entity.setLocation(event.getLocation());
+    entity.setLocation(event.location());
-    entity.setExpiryDate(event.getExpiryDate());
+    entity.setExpiryDate(event.expiryDate());
-    entity.setCreatedAt(event.getCreatedAt());
+    entity.setCreatedAt(event.createdAt());
-    entity.setCancelled(event.isCancelled());
+    entity.setCancelled(event.cancelled());
-    entity.setCancellationReason(event.getCancellationReason());
+    entity.setCancellationReason(event.cancellationReason());
     return entity;
   }
 
   private Event toDomain(EventJpaEntity entity) {
-    var event = new Event();
+    return new Event(
-    event.setId(entity.getId());
+        entity.getId(),
-    event.setEventToken(new EventToken(entity.getEventToken()));
+        new EventToken(entity.getEventToken()),
-    event.setOrganizerToken(new OrganizerToken(entity.getOrganizerToken()));
+        new OrganizerToken(entity.getOrganizerToken()),
-    event.setTitle(entity.getTitle());
+        entity.getTitle(),
-    event.setDescription(entity.getDescription());
+        entity.getDescription(),
-    event.setDateTime(entity.getDateTime());
+        entity.getDateTime(),
-    event.setTimezone(ZoneId.of(entity.getTimezone()));
+        ZoneId.of(entity.getTimezone()),
-    event.setLocation(entity.getLocation());
+        entity.getLocation(),
-    event.setExpiryDate(entity.getExpiryDate());
+        entity.getExpiryDate(),
-    event.setCreatedAt(entity.getCreatedAt());
+        entity.getCreatedAt(),
-    event.setCancelled(entity.isCancelled());
+        entity.isCancelled(),
-    event.setCancellationReason(entity.getCancellationReason());
+        entity.getCancellationReason());
-    return event;
   }
 }

backend/src/main/java/de/fete/adapter/out/persistence/RsvpPersistenceAdapter.java

@@ -43,19 +43,18 @@ public class RsvpPersistenceAdapter implements RsvpRepository {
 
   private RsvpJpaEntity toEntity(Rsvp rsvp) {
     var entity = new RsvpJpaEntity();
-    entity.setId(rsvp.getId());
+    entity.setId(rsvp.id());
-    entity.setRsvpToken(rsvp.getRsvpToken().value());
+    entity.setRsvpToken(rsvp.rsvpToken().value());
-    entity.setEventId(rsvp.getEventId());
+    entity.setEventId(rsvp.eventId());
-    entity.setName(rsvp.getName());
+    entity.setName(rsvp.name());
     return entity;
   }
 
   private Rsvp toDomain(RsvpJpaEntity entity) {
-    var rsvp = new Rsvp();
+    return new Rsvp(
-    rsvp.setId(entity.getId());
+        entity.getId(),
-    rsvp.setRsvpToken(new RsvpToken(entity.getRsvpToken()));
+        new RsvpToken(entity.getRsvpToken()),
-    rsvp.setEventId(entity.getEventId());
+        entity.getEventId(),
-    rsvp.setName(entity.getName());
+        entity.getName());
-    return rsvp;
   }
 }

backend/src/main/java/de/fete/application/service/EventService.java

@@ -1,5 +1,8 @@
 package de.fete.application.service;
 
+import de.fete.application.service.exception.EventAlreadyCancelledException;
+import de.fete.application.service.exception.EventNotFoundException;
+import de.fete.application.service.exception.InvalidOrganizerTokenException;
 import de.fete.domain.model.CreateEventCommand;
 import de.fete.domain.model.Event;
 import de.fete.domain.model.EventToken;
@@ -34,16 +37,19 @@ public class EventService implements CreateEventUseCase, GetEventUseCase, Update
   public Event createEvent(CreateEventCommand command) {
     LocalDate expiryDate = command.dateTime().toLocalDate().plusDays(EXPIRY_DAYS_AFTER_EVENT);
 
-    var event = new Event();
+    var event = new Event(
-    event.setEventToken(EventToken.generate());
+        null,
-    event.setOrganizerToken(OrganizerToken.generate());
+        EventToken.generate(),
-    event.setTitle(command.title());
+        OrganizerToken.generate(),
-    event.setDescription(command.description());
+        command.title(),
-    event.setDateTime(command.dateTime());
+        command.description(),
-    event.setTimezone(command.timezone());
+        command.dateTime(),
-    event.setLocation(command.location());
+        command.timezone(),
-    event.setExpiryDate(expiryDate);
+        command.location(),
-    event.setCreatedAt(OffsetDateTime.now(clock));
+        expiryDate,
+        OffsetDateTime.now(clock),
+        false,
+        null);
 
     return eventRepository.save(event);
   }
@@ -65,16 +71,14 @@ public class EventService implements CreateEventUseCase, GetEventUseCase, Update
     Event event = eventRepository.findByEventToken(eventToken)
         .orElseThrow(() -> new EventNotFoundException(eventToken.value()));
 
-    if (!event.getOrganizerToken().equals(organizerToken)) {
+    if (!event.organizerToken().equals(organizerToken)) {
       throw new InvalidOrganizerTokenException();
     }
 
-    if (event.isCancelled()) {
+    if (event.cancelled()) {
       throw new EventAlreadyCancelledException(eventToken.value());
     }
 
-    event.setCancelled(true);
+    eventRepository.save(event.withCancellation(true, reason));
-    event.setCancellationReason(reason);
-    eventRepository.save(event);
   }
 }

backend/src/main/java/de/fete/application/service/RsvpService.java

@@ -1,5 +1,9 @@
 package de.fete.application.service;
 
+import de.fete.application.service.exception.EventCancelledException;
+import de.fete.application.service.exception.EventExpiredException;
+import de.fete.application.service.exception.EventNotFoundException;
+import de.fete.application.service.exception.InvalidOrganizerTokenException;
 import de.fete.domain.model.Event;
 import de.fete.domain.model.EventToken;
 import de.fete.domain.model.OrganizerToken;
@@ -42,18 +46,15 @@ public class RsvpService
     Event event = eventRepository.findByEventToken(eventToken)
         .orElseThrow(() -> new EventNotFoundException(eventToken.value()));
 
-    if (event.isCancelled()) {
+    if (event.cancelled()) {
       throw new EventCancelledException(eventToken.value());
     }
 
-    if (!event.getExpiryDate().isAfter(LocalDate.now(clock))) {
+    if (!event.expiryDate().isAfter(LocalDate.now(clock))) {
       throw new EventExpiredException(eventToken.value());
     }
 
-    var rsvp = new Rsvp();
+    var rsvp = new Rsvp(null, RsvpToken.generate(), event.id(), name.strip());
-    rsvp.setRsvpToken(RsvpToken.generate());
-    rsvp.setEventId(event.getId());
-    rsvp.setName(name.strip());
 
     return rsvpRepository.save(rsvp);
   }
@@ -63,14 +64,14 @@ public class RsvpService
   public void cancelRsvp(EventToken eventToken, RsvpToken rsvpToken) {
     eventRepository.findByEventToken(eventToken)
         .ifPresent(event ->
-            rsvpRepository.deleteByEventIdAndRsvpToken(event.getId(), rsvpToken));
+            rsvpRepository.deleteByEventIdAndRsvpToken(event.id(), rsvpToken));
   }
 
   @Override
   public long countByEvent(EventToken eventToken) {
     Event event = eventRepository.findByEventToken(eventToken)
         .orElseThrow(() -> new EventNotFoundException(eventToken.value()));
-    return rsvpRepository.countByEventId(event.getId());
+    return rsvpRepository.countByEventId(event.id());
   }
 
   @Override
@@ -78,12 +79,12 @@ public class RsvpService
     Event event = eventRepository.findByEventToken(eventToken)
         .orElseThrow(() -> new EventNotFoundException(eventToken.value()));
 
-    if (!event.getOrganizerToken().equals(organizerToken)) {
+    if (!event.organizerToken().equals(organizerToken)) {
       throw new InvalidOrganizerTokenException();
     }
 
-    return rsvpRepository.findByEventId(event.getId()).stream()
+    return rsvpRepository.findByEventId(event.id()).stream()
-        .map(Rsvp::getName)
+        .map(Rsvp::name)
         .toList();
   }
 }

backend/src/main/java/de/fete/application/service/exception/EventAlreadyCancelledException.java

@@ -1,4 +1,4 @@
-package de.fete.application.service;
+package de.fete.application.service.exception;
 
 import java.util.UUID;
 

backend/src/main/java/de/fete/application/service/exception/EventCancelledException.java

@@ -1,4 +1,4 @@
-package de.fete.application.service;
+package de.fete.application.service.exception;
 
 import java.util.UUID;
 

backend/src/main/java/de/fete/application/service/exception/EventExpiredException.java

@@ -1,4 +1,4 @@
-package de.fete.application.service;
+package de.fete.application.service.exception;
 
 import java.util.UUID;
 

backend/src/main/java/de/fete/application/service/exception/EventNotFoundException.java

@@ -1,4 +1,4 @@
-package de.fete.application.service;
+package de.fete.application.service.exception;
 
 import java.util.UUID;
 

backend/src/main/java/de/fete/application/service/exception/ExpiryDateBeforeEventException.java

@@ -1,4 +1,4 @@
-package de.fete.application.service;
+package de.fete.application.service.exception;
 
 import java.time.LocalDate;
 import java.time.OffsetDateTime;

backend/src/main/java/de/fete/application/service/exception/ExpiryDateInPastException.java

@@ -1,4 +1,4 @@
-package de.fete.application.service;
+package de.fete.application.service.exception;
 
 import java.time.LocalDate;
 

backend/src/main/java/de/fete/application/service/exception/InvalidOrganizerTokenException.java

@@ -1,4 +1,4 @@
-package de.fete.application.service;
+package de.fete.application.service.exception;
 
 /** Thrown when an invalid organizer token is provided. */
 public class InvalidOrganizerTokenException extends RuntimeException {

backend/src/main/java/de/fete/application/service/exception/InvalidTimezoneException.java

@@ -1,4 +1,4 @@
-package de.fete.application.service;
+package de.fete.application.service.exception;
 
 /** Thrown when an invalid IANA timezone ID is provided. */
 public class InvalidTimezoneException extends RuntimeException {

backend/src/main/java/de/fete/application/service/exception/package-info.java

@@ -0,0 +1,4 @@
+/**
+ * Application-layer exceptions thrown by service use case implementations.
+ */
+package de.fete.application.service.exception;

backend/src/main/java/de/fete/domain/model/Event.java

@@ -5,138 +5,26 @@ import java.time.OffsetDateTime;
 import java.time.ZoneId;
 
 /** Domain entity representing an event. */
-public class Event {
+public record Event(
+    Long id,
+    EventToken eventToken,
+    OrganizerToken organizerToken,
+    String title,
+    String description,
+    OffsetDateTime dateTime,
+    ZoneId timezone,
+    String location,
+    LocalDate expiryDate,
+    OffsetDateTime createdAt,
+    boolean cancelled,
+    String cancellationReason
+) {
 
-  private Long id;
+  /** Returns a copy of this event with cancellation applied. */
-  private EventToken eventToken;
+  public Event withCancellation(boolean cancelled, String cancellationReason) {
-  private OrganizerToken organizerToken;
+    return new Event(
-  private String title;
+        id, eventToken, organizerToken, title, description,
-  private String description;
+        dateTime, timezone, location, expiryDate, createdAt,
-  private OffsetDateTime dateTime;
+        cancelled, cancellationReason);
-  private ZoneId timezone;
-  private String location;
-  private LocalDate expiryDate;
-  private OffsetDateTime createdAt;
-  private boolean cancelled;
-  private String cancellationReason;
-
-  /** Returns the internal database ID. */
-  public Long getId() {
-    return id;
-  }
-
-  /** Sets the internal database ID. */
-  public void setId(Long id) {
-    this.id = id;
-  }
-
-  /** Returns the public event token. */
-  public EventToken getEventToken() {
-    return eventToken;
-  }
-
-  /** Sets the public event token. */
-  public void setEventToken(EventToken eventToken) {
-    this.eventToken = eventToken;
-  }
-
-  /** Returns the secret organizer token. */
-  public OrganizerToken getOrganizerToken() {
-    return organizerToken;
-  }
-
-  /** Sets the secret organizer token. */
-  public void setOrganizerToken(OrganizerToken organizerToken) {
-    this.organizerToken = organizerToken;
-  }
-
-  /** Returns the event title. */
-  public String getTitle() {
-    return title;
-  }
-
-  /** Sets the event title. */
-  public void setTitle(String title) {
-    this.title = title;
-  }
-
-  /** Returns the event description. */
-  public String getDescription() {
-    return description;
-  }
-
-  /** Sets the event description. */
-  public void setDescription(String description) {
-    this.description = description;
-  }
-
-  /** Returns the event date and time with UTC offset. */
-  public OffsetDateTime getDateTime() {
-    return dateTime;
-  }
-
-  /** Sets the event date and time. */
-  public void setDateTime(OffsetDateTime dateTime) {
-    this.dateTime = dateTime;
-  }
-
-  /** Returns the IANA timezone. */
-  public ZoneId getTimezone() {
-    return timezone;
-  }
-
-  /** Sets the IANA timezone. */
-  public void setTimezone(ZoneId timezone) {
-    this.timezone = timezone;
-  }
-
-  /** Returns the event location. */
-  public String getLocation() {
-    return location;
-  }
-
-  /** Sets the event location. */
-  public void setLocation(String location) {
-    this.location = location;
-  }
-
-  /** Returns the expiry date after which event data is deleted. */
-  public LocalDate getExpiryDate() {
-    return expiryDate;
-  }
-
-  /** Sets the expiry date. */
-  public void setExpiryDate(LocalDate expiryDate) {
-    this.expiryDate = expiryDate;
-  }
-
-  /** Returns the creation timestamp. */
-  public OffsetDateTime getCreatedAt() {
-    return createdAt;
-  }
-
-  /** Sets the creation timestamp. */
-  public void setCreatedAt(OffsetDateTime createdAt) {
-    this.createdAt = createdAt;
-  }
-
-  /** Returns whether the event has been cancelled. */
-  public boolean isCancelled() {
-    return cancelled;
-  }
-
-  /** Sets the cancelled flag. */
-  public void setCancelled(boolean cancelled) {
-    this.cancelled = cancelled;
-  }
-
-  /** Returns the cancellation reason, if any. */
-  public String getCancellationReason() {
-    return cancellationReason;
-  }
-
-  /** Sets the cancellation reason. */
-  public void setCancellationReason(String cancellationReason) {
-    this.cancellationReason = cancellationReason;
   }
 }

backend/src/main/java/de/fete/domain/model/Rsvp.java

@@ -1,50 +1,9 @@
 package de.fete.domain.model;
 
 /** Domain entity representing an RSVP. */
-public class Rsvp {
+public record Rsvp(
-
+    Long id,
-  private Long id;
+    RsvpToken rsvpToken,
-  private RsvpToken rsvpToken;
+    Long eventId,
-  private Long eventId;
+    String name
-  private String name;
+) {}
-
-  /** Returns the internal database ID. */
-  public Long getId() {
-    return id;
-  }
-
-  /** Sets the internal database ID. */
-  public void setId(Long id) {
-    this.id = id;
-  }
-
-  /** Returns the RSVP token. */
-  public RsvpToken getRsvpToken() {
-    return rsvpToken;
-  }
-
-  /** Sets the RSVP token. */
-  public void setRsvpToken(RsvpToken rsvpToken) {
-    this.rsvpToken = rsvpToken;
-  }
-
-  /** Returns the event ID this RSVP belongs to. */
-  public Long getEventId() {
-    return eventId;
-  }
-
-  /** Sets the event ID. */
-  public void setEventId(Long eventId) {
-    this.eventId = eventId;
-  }
-
-  /** Returns the guest's display name. */
-  public String getName() {
-    return name;
-  }
-
-  /** Sets the guest's display name. */
-  public void setName(String name) {
-    this.name = name;
-  }
-}

backend/src/test/java/de/fete/HexagonalArchitectureTest.java

@@ -4,10 +4,14 @@ import static com.tngtech.archunit.lang.syntax.ArchRuleDefinition.classes;
 import static com.tngtech.archunit.lang.syntax.ArchRuleDefinition.noClasses;
 import static com.tngtech.archunit.library.Architectures.onionArchitecture;
 
+import com.tngtech.archunit.core.domain.JavaClass;
 import com.tngtech.archunit.core.importer.ImportOption;
 import com.tngtech.archunit.junit.AnalyzeClasses;
 import com.tngtech.archunit.junit.ArchTest;
+import com.tngtech.archunit.lang.ArchCondition;
 import com.tngtech.archunit.lang.ArchRule;
+import com.tngtech.archunit.lang.ConditionEvents;
+import com.tngtech.archunit.lang.SimpleConditionEvent;
 
 @AnalyzeClasses(packages = "de.fete", importOptions = ImportOption.DoNotIncludeTests.class)
 class HexagonalArchitectureTest {
@@ -65,4 +69,24 @@ class HexagonalArchitectureTest {
   static final ArchRule webAdapterMustNotDependOnOutboundPorts = noClasses()
       .that().resideInAPackage("de.fete.adapter.in.web..")
       .should().dependOnClassesThat().resideInAPackage("de.fete.domain.port.out..");
+
+  @ArchTest
+  static final ArchRule domainModelsMustBeRecords = classes()
+      .that().resideInAPackage("de.fete.domain.model..")
+      .and().doNotHaveSimpleName("package-info")
+      .should(beRecords());
+
+  private static ArchCondition<JavaClass> beRecords() {
+    return new ArchCondition<>("be records") {
+      @Override
+      public void check(JavaClass javaClass,
+          ConditionEvents events) {
+        boolean isRecord = javaClass.reflect().isRecord();
+        if (!isRecord) {
+          events.add(SimpleConditionEvent.violated(javaClass,
+              javaClass.getFullName() + " is not a record"));
+        }
+      }
+    };
+  }
 }

backend/src/test/java/de/fete/adapter/out/persistence/EventPersistenceAdapterIntegrationTest.java

@@ -42,7 +42,7 @@ class EventPersistenceAdapterIntegrationTest {
 
     eventRepository.deleteExpired();
 
-    assertThat(eventRepository.findByEventToken(saved.getEventToken())).isPresent();
+    assertThat(eventRepository.findByEventToken(saved.eventToken())).isPresent();
   }
 
   @Test
@@ -52,7 +52,7 @@ class EventPersistenceAdapterIntegrationTest {
 
     eventRepository.deleteExpired();
 
-    assertThat(eventRepository.findByEventToken(saved.getEventToken())).isPresent();
+    assertThat(eventRepository.findByEventToken(saved.eventToken())).isPresent();
   }
 
   @Test
@@ -66,16 +66,18 @@ class EventPersistenceAdapterIntegrationTest {
   }
 
   private Event buildEvent(String title, LocalDate expiryDate) {
-    var event = new Event();
+    return new Event(
-    event.setEventToken(EventToken.generate());
+        null,
-    event.setOrganizerToken(OrganizerToken.generate());
+        EventToken.generate(),
-    event.setTitle(title);
+        OrganizerToken.generate(),
-    event.setDescription("Test description");
+        title,
-    event.setDateTime(OffsetDateTime.of(2026, 6, 15, 20, 0, 0, 0, ZoneOffset.ofHours(2)));
+        "Test description",
-    event.setTimezone(ZoneId.of("Europe/Berlin"));
+        OffsetDateTime.of(2026, 6, 15, 20, 0, 0, 0, ZoneOffset.ofHours(2)),
-    event.setLocation("Test Location");
+        ZoneId.of("Europe/Berlin"),
-    event.setExpiryDate(expiryDate);
+        "Test Location",
-    event.setCreatedAt(OffsetDateTime.now());
+        expiryDate,
-    return event;
+        OffsetDateTime.now(),
+        false,
+        null);
   }
 }

backend/src/test/java/de/fete/adapter/out/persistence/EventPersistenceAdapterTest.java

@@ -30,8 +30,8 @@ class EventPersistenceAdapterTest {
 
     Event saved = eventRepository.save(event);
 
-    assertThat(saved.getId()).isNotNull();
+    assertThat(saved.id()).isNotNull();
-    assertThat(saved.getTitle()).isEqualTo("Test Event");
+    assertThat(saved.title()).isEqualTo("Test Event");
   }
 
   @Test
@@ -39,11 +39,11 @@ class EventPersistenceAdapterTest {
     Event event = buildEvent();
     Event saved = eventRepository.save(event);
 
-    Optional<Event> found = eventRepository.findByEventToken(saved.getEventToken());
+    Optional<Event> found = eventRepository.findByEventToken(saved.eventToken());
 
     assertThat(found).isPresent();
-    assertThat(found.get().getTitle()).isEqualTo("Test Event");
+    assertThat(found.get().title()).isEqualTo("Test Event");
-    assertThat(found.get().getId()).isEqualTo(saved.getId());
+    assertThat(found.get().id()).isEqualTo(saved.id());
   }
 
   @Test
@@ -61,42 +61,47 @@ class EventPersistenceAdapterTest {
     OffsetDateTime createdAt =
         OffsetDateTime.of(2026, 3, 4, 12, 0, 0, 0, ZoneOffset.UTC);
 
-    var event = new Event();
+    var event = new Event(
-    event.setEventToken(EventToken.generate());
+        null,
-    event.setOrganizerToken(OrganizerToken.generate());
+        EventToken.generate(),
-    event.setTitle("Full Event");
+        OrganizerToken.generate(),
-    event.setDescription("A detailed description");
+        "Full Event",
-    event.setDateTime(dateTime);
+        "A detailed description",
-    event.setTimezone(ZoneId.of("Europe/Berlin"));
+        dateTime,
-    event.setLocation("Berlin, Germany");
+        ZoneId.of("Europe/Berlin"),
-    event.setExpiryDate(expiryDate);
+        "Berlin, Germany",
-    event.setCreatedAt(createdAt);
+        expiryDate,
+        createdAt,
+        false,
+        null);
 
     Event saved = eventRepository.save(event);
-    Event found = eventRepository.findByEventToken(saved.getEventToken()).orElseThrow();
+    Event found = eventRepository.findByEventToken(saved.eventToken()).orElseThrow();
 
-    assertThat(found.getEventToken()).isEqualTo(event.getEventToken());
+    assertThat(found.eventToken()).isEqualTo(event.eventToken());
-    assertThat(found.getOrganizerToken()).isEqualTo(event.getOrganizerToken());
+    assertThat(found.organizerToken()).isEqualTo(event.organizerToken());
-    assertThat(found.getTitle()).isEqualTo("Full Event");
+    assertThat(found.title()).isEqualTo("Full Event");
-    assertThat(found.getDescription()).isEqualTo("A detailed description");
+    assertThat(found.description()).isEqualTo("A detailed description");
-    assertThat(found.getDateTime().toInstant()).isEqualTo(dateTime.toInstant());
+    assertThat(found.dateTime().toInstant()).isEqualTo(dateTime.toInstant());
-    assertThat(found.getTimezone()).isEqualTo(ZoneId.of("Europe/Berlin"));
+    assertThat(found.timezone()).isEqualTo(ZoneId.of("Europe/Berlin"));
-    assertThat(found.getLocation()).isEqualTo("Berlin, Germany");
+    assertThat(found.location()).isEqualTo("Berlin, Germany");
-    assertThat(found.getExpiryDate()).isEqualTo(expiryDate);
+    assertThat(found.expiryDate()).isEqualTo(expiryDate);
-    assertThat(found.getCreatedAt().toInstant()).isEqualTo(createdAt.toInstant());
+    assertThat(found.createdAt().toInstant()).isEqualTo(createdAt.toInstant());
   }
 
   private Event buildEvent() {
-    var event = new Event();
+    return new Event(
-    event.setEventToken(EventToken.generate());
+        null,
-    event.setOrganizerToken(OrganizerToken.generate());
+        EventToken.generate(),
-    event.setTitle("Test Event");
+        OrganizerToken.generate(),
-    event.setDescription("Test description");
+        "Test Event",
-    event.setDateTime(OffsetDateTime.now().plusDays(7));
+        "Test description",
-    event.setTimezone(ZoneId.of("Europe/Berlin"));
+        OffsetDateTime.now().plusDays(7),
-    event.setLocation("Somewhere");
+        ZoneId.of("Europe/Berlin"),
-    event.setExpiryDate(LocalDate.now().plusDays(30));
+        "Somewhere",
-    event.setCreatedAt(OffsetDateTime.now());
+        LocalDate.now().plusDays(30),
-    return event;
+        OffsetDateTime.now(),
+        false,
+        null);
   }
 }

backend/src/test/java/de/fete/application/service/EventServiceCancelTest.java

@@ -7,7 +7,9 @@ import static org.mockito.Mockito.never;
 import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.when;
 
-import de.fete.application.service.EventAlreadyCancelledException;
+import de.fete.application.service.exception.EventAlreadyCancelledException;
+import de.fete.application.service.exception.EventNotFoundException;
+import de.fete.application.service.exception.InvalidOrganizerTokenException;
 import de.fete.domain.model.Event;
 import de.fete.domain.model.EventToken;
 import de.fete.domain.model.OrganizerToken;
@@ -46,10 +48,8 @@ class EventServiceCancelTest {
   void cancelEventDelegatesToDomainAndSaves() {
     EventToken eventToken = EventToken.generate();
     OrganizerToken organizerToken = OrganizerToken.generate();
-    var event = new Event();
+    var event = new Event(null, eventToken, organizerToken, null, null, null, null, null, null,
-    event.setEventToken(eventToken);
+        null, false, null);
-    event.setOrganizerToken(organizerToken);
-    event.setCancelled(false);
 
     when(eventRepository.findByEventToken(eventToken))
         .thenReturn(Optional.of(event));
@@ -60,18 +60,16 @@ class EventServiceCancelTest {
 
     ArgumentCaptor<Event> captor = ArgumentCaptor.forClass(Event.class);
     verify(eventRepository).save(captor.capture());
-    assertThat(captor.getValue().isCancelled()).isTrue();
+    assertThat(captor.getValue().cancelled()).isTrue();
-    assertThat(captor.getValue().getCancellationReason()).isEqualTo("Venue unavailable");
+    assertThat(captor.getValue().cancellationReason()).isEqualTo("Venue unavailable");
   }
 
   @Test
   void cancelEventWithNullReason() {
     EventToken eventToken = EventToken.generate();
     OrganizerToken organizerToken = OrganizerToken.generate();
-    var event = new Event();
+    var event = new Event(null, eventToken, organizerToken, null, null, null, null, null, null,
-    event.setEventToken(eventToken);
+        null, false, null);
-    event.setOrganizerToken(organizerToken);
-    event.setCancelled(false);
 
     when(eventRepository.findByEventToken(eventToken))
         .thenReturn(Optional.of(event));
@@ -82,8 +80,8 @@ class EventServiceCancelTest {
 
     ArgumentCaptor<Event> captor = ArgumentCaptor.forClass(Event.class);
     verify(eventRepository).save(captor.capture());
-    assertThat(captor.getValue().isCancelled()).isTrue();
+    assertThat(captor.getValue().cancelled()).isTrue();
-    assertThat(captor.getValue().getCancellationReason()).isNull();
+    assertThat(captor.getValue().cancellationReason()).isNull();
   }
 
   @Test
@@ -104,9 +102,8 @@ class EventServiceCancelTest {
   void cancelEventThrows403WhenWrongOrganizerToken() {
     EventToken eventToken = EventToken.generate();
     OrganizerToken correctToken = OrganizerToken.generate();
-    var event = new Event();
+    var event = new Event(null, eventToken, correctToken, null, null, null, null, null, null,
-    event.setEventToken(eventToken);
+        null, false, null);
-    event.setOrganizerToken(correctToken);
 
     when(eventRepository.findByEventToken(eventToken))
         .thenReturn(Optional.of(event));
@@ -122,10 +119,8 @@ class EventServiceCancelTest {
   void cancelEventThrows409WhenAlreadyCancelled() {
     EventToken eventToken = EventToken.generate();
     OrganizerToken organizerToken = OrganizerToken.generate();
-    var event = new Event();
+    var event = new Event(null, eventToken, organizerToken, null, null, null, null, null, null,
-    event.setEventToken(eventToken);
+        null, true, null);
-    event.setOrganizerToken(organizerToken);
-    event.setCancelled(true);
 
     when(eventRepository.findByEventToken(eventToken))
         .thenReturn(Optional.of(event));

backend/src/test/java/de/fete/application/service/EventServiceTest.java

@@ -57,13 +57,13 @@ class EventServiceTest {
 
     Event result = eventService.createEvent(command);
 
-    assertThat(result.getTitle()).isEqualTo("Birthday Party");
+    assertThat(result.title()).isEqualTo("Birthday Party");
-    assertThat(result.getDescription()).isEqualTo("Come celebrate!");
+    assertThat(result.description()).isEqualTo("Come celebrate!");
-    assertThat(result.getTimezone()).isEqualTo(ZONE);
+    assertThat(result.timezone()).isEqualTo(ZONE);
-    assertThat(result.getLocation()).isEqualTo("Berlin");
+    assertThat(result.location()).isEqualTo("Berlin");
-    assertThat(result.getEventToken()).isNotNull();
+    assertThat(result.eventToken()).isNotNull();
-    assertThat(result.getOrganizerToken()).isNotNull();
+    assertThat(result.organizerToken()).isNotNull();
-    assertThat(result.getCreatedAt()).isEqualTo(OffsetDateTime.ofInstant(FIXED_INSTANT, ZONE));
+    assertThat(result.createdAt()).isEqualTo(OffsetDateTime.ofInstant(FIXED_INSTANT, ZONE));
   }
 
   @Test
@@ -80,7 +80,7 @@ class EventServiceTest {
 
     ArgumentCaptor<Event> captor = ArgumentCaptor.forClass(Event.class);
     verify(eventRepository, times(1)).save(captor.capture());
-    assertThat(captor.getValue().getTitle()).isEqualTo("Test");
+    assertThat(captor.getValue().title()).isEqualTo("Test");
   }
 
   @Test
@@ -96,7 +96,7 @@ class EventServiceTest {
 
     Event result = eventService.createEvent(command);
 
-    assertThat(result.getExpiryDate()).isEqualTo(eventDate.plusDays(7));
+    assertThat(result.expiryDate()).isEqualTo(eventDate.plusDays(7));
   }
 
   // --- GetEventUseCase tests (T004) ---
@@ -104,16 +104,15 @@ class EventServiceTest {
   @Test
   void getByEventTokenReturnsEvent() {
     EventToken token = EventToken.generate();
-    var event = new Event();
+    var event = new Event(null, token, null, "Found Event", null, null, null, null, null, null,
-    event.setEventToken(token);
+        false, null);
-    event.setTitle("Found Event");
     when(eventRepository.findByEventToken(token))
         .thenReturn(Optional.of(event));
 
     Optional<Event> result = eventService.getByEventToken(token);
 
     assertThat(result).isPresent();
-    assertThat(result.get().getTitle()).isEqualTo("Found Event");
+    assertThat(result.get().title()).isEqualTo("Found Event");
   }
 
   @Test
@@ -142,6 +141,6 @@ class EventServiceTest {
 
     Event result = eventService.createEvent(command);
 
-    assertThat(result.getTimezone()).isEqualTo(ZoneId.of("America/New_York"));
+    assertThat(result.timezone()).isEqualTo(ZoneId.of("America/New_York"));
   }
 }

backend/src/test/java/de/fete/application/service/RsvpServiceTest.java

@@ -6,6 +6,10 @@ import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.when;
 
+import de.fete.application.service.exception.EventCancelledException;
+import de.fete.application.service.exception.EventExpiredException;
+import de.fete.application.service.exception.EventNotFoundException;
+import de.fete.application.service.exception.InvalidOrganizerTokenException;
 import de.fete.domain.model.Event;
 import de.fete.domain.model.EventToken;
 import de.fete.domain.model.OrganizerToken;
@@ -51,23 +55,23 @@ class RsvpServiceTest {
 
   @Test
   void createRsvpSucceedsForActiveEvent() {
-    Event event = buildActiveEvent();
+    Event event = buildActiveEvent(TODAY.plusDays(30));
-    EventToken token = event.getEventToken();
+    EventToken token = event.eventToken();
     when(eventRepository.findByEventToken(token)).thenReturn(Optional.of(event));
     when(rsvpRepository.save(any(Rsvp.class)))
         .thenAnswer(invocation -> invocation.getArgument(0));
 
     Rsvp result = rsvpService.createRsvp(token, "Max Mustermann");
 
-    assertThat(result.getName()).isEqualTo("Max Mustermann");
+    assertThat(result.name()).isEqualTo("Max Mustermann");
-    assertThat(result.getRsvpToken()).isNotNull();
+    assertThat(result.rsvpToken()).isNotNull();
-    assertThat(result.getEventId()).isEqualTo(event.getId());
+    assertThat(result.eventId()).isEqualTo(event.id());
   }
 
   @Test
   void createRsvpPersistsViaRepository() {
-    Event event = buildActiveEvent();
+    Event event = buildActiveEvent(TODAY.plusDays(30));
-    EventToken token = event.getEventToken();
+    EventToken token = event.eventToken();
     when(eventRepository.findByEventToken(token)).thenReturn(Optional.of(event));
     when(rsvpRepository.save(any(Rsvp.class)))
         .thenAnswer(invocation -> invocation.getArgument(0));
@@ -76,8 +80,8 @@ class RsvpServiceTest {
 
     ArgumentCaptor<Rsvp> captor = ArgumentCaptor.forClass(Rsvp.class);
     verify(rsvpRepository).save(captor.capture());
-    assertThat(captor.getValue().getName()).isEqualTo("Test Guest");
+    assertThat(captor.getValue().name()).isEqualTo("Test Guest");
-    assertThat(captor.getValue().getEventId()).isEqualTo(event.getId());
+    assertThat(captor.getValue().eventId()).isEqualTo(event.id());
   }
 
   @Test
@@ -91,22 +95,21 @@ class RsvpServiceTest {
 
   @Test
   void createRsvpTrimsName() {
-    Event event = buildActiveEvent();
+    Event event = buildActiveEvent(TODAY.plusDays(30));
-    EventToken token = event.getEventToken();
+    EventToken token = event.eventToken();
     when(eventRepository.findByEventToken(token)).thenReturn(Optional.of(event));
     when(rsvpRepository.save(any(Rsvp.class)))
         .thenAnswer(invocation -> invocation.getArgument(0));
 
     Rsvp result = rsvpService.createRsvp(token, "  Max  ");
 
-    assertThat(result.getName()).isEqualTo("Max");
+    assertThat(result.name()).isEqualTo("Max");
   }
 
   @Test
   void createRsvpThrowsWhenEventExpired() {
-    var event = buildActiveEvent();
+    Event event = buildActiveEvent(TODAY.minusDays(1));
-    event.setExpiryDate(TODAY.minusDays(1));
+    EventToken token = event.eventToken();
-    EventToken token = event.getEventToken();
     when(eventRepository.findByEventToken(token)).thenReturn(Optional.of(event));
 
     assertThatThrownBy(() -> rsvpService.createRsvp(token, "Late Guest"))
@@ -115,9 +118,8 @@ class RsvpServiceTest {
 
   @Test
   void createRsvpThrowsWhenEventExpiresToday() {
-    var event = buildActiveEvent();
+    Event event = buildActiveEvent(TODAY);
-    event.setExpiryDate(TODAY);
+    EventToken token = event.eventToken();
-    EventToken token = event.getEventToken();
     when(eventRepository.findByEventToken(token)).thenReturn(Optional.of(event));
 
     assertThatThrownBy(() -> rsvpService.createRsvp(token, "Late Guest"))
@@ -126,12 +128,12 @@ class RsvpServiceTest {
 
   @Test
   void getAttendeeNamesReturnsNamesInOrder() {
-    Event event = buildActiveEvent();
+    Event event = buildActiveEvent(TODAY.plusDays(30));
-    EventToken token = event.getEventToken();
+    EventToken token = event.eventToken();
-    OrganizerToken orgToken = event.getOrganizerToken();
+    OrganizerToken orgToken = event.organizerToken();
     when(eventRepository.findByEventToken(token))
         .thenReturn(Optional.of(event));
-    when(rsvpRepository.findByEventId(event.getId()))
+    when(rsvpRepository.findByEventId(event.id()))
         .thenReturn(List.of(
             buildRsvp(1L, "Alice"),
             buildRsvp(2L, "Bob"),
@@ -144,12 +146,12 @@ class RsvpServiceTest {
 
   @Test
   void getAttendeeNamesReturnsEmptyListWhenNoRsvps() {
-    Event event = buildActiveEvent();
+    Event event = buildActiveEvent(TODAY.plusDays(30));
-    EventToken token = event.getEventToken();
+    EventToken token = event.eventToken();
-    OrganizerToken orgToken = event.getOrganizerToken();
+    OrganizerToken orgToken = event.organizerToken();
     when(eventRepository.findByEventToken(token))
         .thenReturn(Optional.of(event));
-    when(rsvpRepository.findByEventId(event.getId()))
+    when(rsvpRepository.findByEventId(event.id()))
         .thenReturn(List.of());
 
     List<String> names = rsvpService.getAttendeeNames(token, orgToken);
@@ -171,8 +173,8 @@ class RsvpServiceTest {
 
   @Test
   void getAttendeeNamesThrowsWhenOrganizerTokenInvalid() {
-    Event event = buildActiveEvent();
+    Event event = buildActiveEvent(TODAY.plusDays(30));
-    EventToken token = event.getEventToken();
+    EventToken token = event.eventToken();
     OrganizerToken wrongToken = OrganizerToken.generate();
     when(eventRepository.findByEventToken(token))
         .thenReturn(Optional.of(event));
@@ -183,38 +185,33 @@ class RsvpServiceTest {
   }
 
   private Rsvp buildRsvp(Long id, String name) {
-    var rsvp = new Rsvp();
+    return new Rsvp(id, RsvpToken.generate(), 1L, name);
-    rsvp.setId(id);
-    rsvp.setRsvpToken(RsvpToken.generate());
-    rsvp.setEventId(1L);
-    rsvp.setName(name);
-    return rsvp;
   }
 
   @Test
   void cancelRsvpDeletesWhenEventAndRsvpExist() {
-    Event event = buildActiveEvent();
+    Event event = buildActiveEvent(TODAY.plusDays(30));
-    EventToken token = event.getEventToken();
+    EventToken token = event.eventToken();
     RsvpToken rsvpToken = RsvpToken.generate();
     when(eventRepository.findByEventToken(token)).thenReturn(Optional.of(event));
-    when(rsvpRepository.deleteByEventIdAndRsvpToken(event.getId(), rsvpToken)).thenReturn(true);
+    when(rsvpRepository.deleteByEventIdAndRsvpToken(event.id(), rsvpToken)).thenReturn(true);
 
     rsvpService.cancelRsvp(token, rsvpToken);
 
-    verify(rsvpRepository).deleteByEventIdAndRsvpToken(event.getId(), rsvpToken);
+    verify(rsvpRepository).deleteByEventIdAndRsvpToken(event.id(), rsvpToken);
   }
 
   @Test
   void cancelRsvpSucceedsWhenRsvpNotFound() {
-    Event event = buildActiveEvent();
+    Event event = buildActiveEvent(TODAY.plusDays(30));
-    EventToken token = event.getEventToken();
+    EventToken token = event.eventToken();
     RsvpToken rsvpToken = RsvpToken.generate();
     when(eventRepository.findByEventToken(token)).thenReturn(Optional.of(event));
-    when(rsvpRepository.deleteByEventIdAndRsvpToken(event.getId(), rsvpToken)).thenReturn(false);
+    when(rsvpRepository.deleteByEventIdAndRsvpToken(event.id(), rsvpToken)).thenReturn(false);
 
     rsvpService.cancelRsvp(token, rsvpToken);
 
-    verify(rsvpRepository).deleteByEventIdAndRsvpToken(event.getId(), rsvpToken);
+    verify(rsvpRepository).deleteByEventIdAndRsvpToken(event.id(), rsvpToken);
   }
 
   @Test
@@ -226,16 +223,19 @@ class RsvpServiceTest {
     rsvpService.cancelRsvp(token, rsvpToken);
   }
 
-  private Event buildActiveEvent() {
+  private Event buildActiveEvent(LocalDate expiryDate) {
-    var event = new Event();
+    return new Event(
-    event.setId(1L);
+        1L,
-    event.setEventToken(EventToken.generate());
+        EventToken.generate(),
-    event.setOrganizerToken(OrganizerToken.generate());
+        OrganizerToken.generate(),
-    event.setTitle("Test Event");
+        "Test Event",
-    event.setDateTime(OffsetDateTime.of(2026, 6, 15, 20, 0, 0, 0, ZoneOffset.ofHours(2)));
+        null,
-    event.setTimezone(ZONE);
+        OffsetDateTime.of(2026, 6, 15, 20, 0, 0, 0, ZoneOffset.ofHours(2)),
-    event.setExpiryDate(TODAY.plusDays(30));
+        ZONE,
-    event.setCreatedAt(OffsetDateTime.now());
+        null,
-    return event;
+        expiryDate,
+        OffsetDateTime.now(),
+        false,
+        null);
   }
 }