fix: Request validation in UserService

src/main/java/eu/ztsh/wymiana/service/UserService.java

@@ -4,8 +4,8 @@ import eu.ztsh.wymiana.data.repository.UserRepository;
 import eu.ztsh.wymiana.exception.UserAlreadyExistsException;
 import eu.ztsh.wymiana.model.User;
 import eu.ztsh.wymiana.util.UserMapper;
+import eu.ztsh.wymiana.validation.InstanceValidator;
 import eu.ztsh.wymiana.web.model.UserCreateRequest;
-import jakarta.validation.Valid;
 import lombok.RequiredArgsConstructor;
 import org.springframework.stereotype.Service;
 
@@ -16,8 +16,10 @@ import java.util.Optional;
 public class UserService {
 
     private final UserRepository userRepository;
+    private final InstanceValidator validator;
 
-    public User create(@Valid UserCreateRequest request) {
+    public User create(UserCreateRequest request) {
+        validator.validate(request);
         if (userRepository.findById(request.pesel()).isPresent()) {
             throw new UserAlreadyExistsException(request);
         }

src/main/java/eu/ztsh/wymiana/validation/Adult.java

@@ -16,9 +16,12 @@ import static java.lang.annotation.RetentionPolicy.RUNTIME;
 @Constraint(validatedBy = AdultValidator.class)
 @Documented
 public @interface Adult {
-    String message() default "{jakarta.validation.constraints.Adult.message}";
+    String message() default MESSAGE;
 
     Class<?>[] groups() default { };
 
     Class<? extends Payload>[] payload() default { };
+
+    String MESSAGE = "The person has not reached the age of 18";
+
 }

src/main/java/eu/ztsh/wymiana/validation/InstanceValidator.java

@@ -0,0 +1,20 @@
+package eu.ztsh.wymiana.validation;
+
+import jakarta.validation.Validator;
+
+public class InstanceValidator {
+
+    private final Validator validator;
+
+    public InstanceValidator(Validator validator) {
+        this.validator = validator;
+    }
+
+    public <T> void validate(T t, Class<?>... classes) {
+        var violations = validator.validate(t, classes);
+        if (!violations.isEmpty()) {
+            throw new ValidationFailedException(violations);
+        }
+    }
+
+}

src/main/java/eu/ztsh/wymiana/validation/InstanceValidatorFactory.java

@@ -0,0 +1,18 @@
+package eu.ztsh.wymiana.validation;
+
+import jakarta.validation.Validation;
+import jakarta.validation.ValidatorFactory;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+
+@Configuration
+public class InstanceValidatorFactory {
+
+    @Bean
+    public InstanceValidator instanceValidator() {
+        try (ValidatorFactory factory = Validation.buildDefaultValidatorFactory()) {
+            return new InstanceValidator(factory.getValidator());
+        }
+    }
+
+}

src/main/java/eu/ztsh/wymiana/validation/ValidationFailedException.java

@@ -0,0 +1,20 @@
+package eu.ztsh.wymiana.validation;
+
+import jakarta.validation.ConstraintViolation;
+import lombok.Getter;
+
+import java.util.Set;
+import java.util.stream.Collectors;
+
+@Getter
+public class ValidationFailedException extends RuntimeException {
+
+    private final transient Set<?> violations;
+
+    public <T> ValidationFailedException(Set<ConstraintViolation<T>> violations) {
+        super("Validation failed: %s".formatted(violations.stream()
+            .map(ConstraintViolation::getMessage).collect(Collectors.joining(System.lineSeparator()))));
+        this.violations = violations;
+    }
+
+}

src/main/java/eu/ztsh/wymiana/web/model/UserCreateRequest.java

@@ -3,7 +3,9 @@ package eu.ztsh.wymiana.web.model;
 import eu.ztsh.wymiana.validation.Adult;
 import jakarta.validation.constraints.Min;
 import jakarta.validation.constraints.NotNull;
+import lombok.Builder;
 
+@Builder
 public record UserCreateRequest(
     @NotNull String name,
     @NotNull String surname,