spring-projectsgh-4901: introduce ValidatingEntityCallback

Author: rfelgent

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/mapping/event/ValidatingEntityCallback.java

@@ -15,6 +15,7 @@
  */
 package org.springframework.data.mongodb.core.mapping.event;
 
+import jakarta.validation.ConstraintViolation;
 import jakarta.validation.ConstraintViolationException;
 import jakarta.validation.Validator;
 import java.util.Set;
@@ -25,7 +26,7 @@
 import org.springframework.util.Assert;
 
 /**
- * javax.validation dependant entities validator.
+ * JSR-303 dependant entities validator.
  * <p>
  * When it is registered as Spring component its automatically invoked
  * after any {@link AbstractMongoEventListener} and before entities are saved in database.
@@ -39,7 +40,7 @@ public class ValidatingEntityCallback implements BeforeSaveCallback<Object>, Ord
 
 	private static final Log LOG = LogFactory.getLog(ValidatingEntityCallback.class);
 
-	// TODO: discuss with spring team, if a handler encapsulating validation logic makes more sense (similar to "AuditingHandler")
+	// TODO: create a validation handler (similar to "AuditingHandler") an reference it from "ValidatingMongoEventListener" and "ValidatingMongoEventListener"
 	private final Validator validator;
 
 	/**
@@ -48,7 +49,6 @@ public class ValidatingEntityCallback implements BeforeSaveCallback<Object>, Ord
 	 * @param validator must not be {@literal null}.
 	 */
 	public ValidatingEntityCallback(Validator validator) {
-
 		Assert.notNull(validator, "Validator must not be null");
 		this.validator = validator;
 	}
@@ -60,12 +60,11 @@ public Object onBeforeSave(Object entity, Document document, String collection)
 		if (LOG.isDebugEnabled()) {
 			LOG.debug(String.format("Validating object: %s", entity));
 		}
-		Set violations = validator.validate(entity);
+		Set<ConstraintViolation<Object>> violations = validator.validate(entity);
 
 		if (!violations.isEmpty()) {
-
 			if (LOG.isDebugEnabled()) {
-				LOG.info(String.format("During object: %s validation violations found: %s", event.getSource(), violations));
+				LOG.info(String.format("During object: %s validation violations found: %s", entity, violations));
 			}
 			throw new ConstraintViolationException(violations);
 		}

spring-data-mongodb/src/test/java/org/springframework/data/mongodb/core/mapping/event/ValidatingEntityCallbackTests.java

@@ -0,0 +1,73 @@
+/*
+ * Copyright 2012-2025 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.data.mongodb.core.mapping.event;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
+
+import jakarta.validation.ConstraintViolationException;
+import jakarta.validation.Validation;
+import jakarta.validation.ValidatorFactory;
+import jakarta.validation.constraints.Min;
+import jakarta.validation.constraints.NotNull;
+import org.bson.Document;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+/**
+ * Unit test for {@link ValidatingEntityCallback}.
+ *
+ * @author Rene Felgenträger
+ */
+class ValidatingEntityCallbackTests {
+
+  private ValidatingEntityCallback callback;
+
+  @BeforeEach
+  public void setUp() {
+    try (ValidatorFactory factory = Validation.buildDefaultValidatorFactory()) {
+      callback = new ValidatingEntityCallback(factory.getValidator());
+    }
+  }
+
+  @Test
+  void invalidModel_throwsException() {
+    Coordinates coordinates = new Coordinates(-1, -1);
+
+    assertThatExceptionOfType(ConstraintViolationException.class)
+        .isThrownBy(() -> callback.onBeforeSave(coordinates, coordinates.toDocument(), "coordinates"))
+        .satisfies(e -> assertThat(e.getConstraintViolations()).hasSize(2));
+  }
+
+  @Test
+  void validModel_noException() {
+    Coordinates coordinates = new Coordinates(0, 0);
+    Object entity = callback.onBeforeSave(coordinates, coordinates.toDocument(), "coordinates");
+    assertThat(entity).isEqualTo(coordinates);
+  }
+
+  record Coordinates(@NotNull @Min(0) Integer x, @NotNull @Min(0) Integer y) {
+
+    Document toDocument() {
+      return Document.parse("""
+          {
+            "x": %d,
+            "y": %d
+          }
+          """.formatted(x, y));
+    }
+  }
+}