add custom required one field validator

dmp-backend/core/pom.xml

@@ -48,7 +48,12 @@
 			<groupId>org.eclipse.angus</groupId>
 			<artifactId>jakarta.mail</artifactId>
 		</dependency>
-	</dependencies>
+        <dependency>
+            <groupId>commons-beanutils</groupId>
+            <artifactId>commons-beanutils</artifactId>
+            <version>1.9.4</version>
+        </dependency>
+    </dependencies>
 
     <build>
         <plugins>

dmp-backend/core/src/main/java/eu/eudat/commons/validation/RequiredOneField.java

@@ -0,0 +1,21 @@
+package eu.eudat.commons.validation;
+
+import jakarta.validation.Constraint;
+import jakarta.validation.Payload;
+
+import java.lang.annotation.*;
+
+@Constraint( validatedBy = { RequiredOneFieldValidator.class } )
+@Documented
+@Target( { ElementType.TYPE } )
+@Retention( RetentionPolicy.RUNTIME )
+public @interface RequiredOneField {
+
+    String message() default "One field is required";
+
+    Class<?>[] groups() default {};
+
+    Class<? extends Payload>[] payload() default {};
+
+    String[] fieldNames();
+}

dmp-backend/core/src/main/java/eu/eudat/commons/validation/RequiredOneFieldValidator.java

@@ -0,0 +1,40 @@
+package eu.eudat.commons.validation;
+
+import jakarta.validation.ConstraintValidator;
+import jakarta.validation.ConstraintValidatorContext;
+import org.apache.commons.beanutils.PropertyUtils;
+
+
+public class RequiredOneFieldValidator implements ConstraintValidator<RequiredOneField, Object> {
+
+    private String[] fieldNames;
+
+    public void initialize(RequiredOneField constraintAnnotation) {
+        this.fieldNames = constraintAnnotation.fieldNames();
+    }
+
+    public boolean isValid(Object object, ConstraintValidatorContext constraintContext) {
+
+        if (object == null) {
+            return true;
+        }
+        int requiredCount = 0;
+        try {
+            for (String fieldName:fieldNames){
+
+                Object property = PropertyUtils.getProperty(object, fieldName);
+                if (property != null) {
+                    requiredCount = requiredCount + 1;
+                }
+            }
+            if (requiredCount == 1){
+                return true;
+            }
+            return false;
+        } catch (Exception e) {
+            return false;
+        }
+    }
+
+}
+

dmp-backend/core/src/main/java/eu/eudat/model/persist/DmpUserInvitePersist.java

@@ -3,12 +3,16 @@ package eu.eudat.model.persist;
 import eu.eudat.commons.enums.DmpUserRole;
 import eu.eudat.commons.validation.ValidEnum;
 import jakarta.validation.Valid;
+import jakarta.validation.constraints.NotEmpty;
+import jakarta.validation.constraints.NotNull;
 
 import java.util.List;
 
 public class DmpUserInvitePersist {
 
     @Valid
+    @NotNull
+    @NotEmpty
     private List<DmpUserInviteTypePersist> users;
 
     @ValidEnum(message = "{validation.empty}")

dmp-backend/core/src/main/java/eu/eudat/model/persist/DmpUserInviteTypePersist.java

@@ -1,8 +1,10 @@
 package eu.eudat.model.persist;
 
+import eu.eudat.commons.validation.RequiredOneField;
 
 import java.util.UUID;
 
+@RequiredOneField(fieldNames={"userId","email"})
 public class DmpUserInviteTypePersist {
     
     private UUID userId;