From 1c79fa820f7402c4f763148a771bb985827cceef Mon Sep 17 00:00:00 2001
From: Mark Paluch <mark.paluch@broadcom.com>
Date: Mon, 25 Nov 2024 09:26:55 +0100
Subject: [PATCH] Consider `NULLS` precedence using `Sort` for Criteria
 Queries.

Closes: #3587
Original Pull Request: #3695
---
 .../data/jpa/repository/query/QueryUtils.java | 23 ++++++++++++-------
 .../query/QueryUtilsIntegrationTests.java     | 11 +++++----
 2 files changed, 22 insertions(+), 12 deletions(-)

diff --git a/spring-data-jpa/src/main/java/org/springframework/data/jpa/repository/query/QueryUtils.java b/spring-data-jpa/src/main/java/org/springframework/data/jpa/repository/query/QueryUtils.java
index e625c9460f..302da71f18 100644
--- a/spring-data-jpa/src/main/java/org/springframework/data/jpa/repository/query/QueryUtils.java
+++ b/spring-data-jpa/src/main/java/org/springframework/data/jpa/repository/query/QueryUtils.java
@@ -29,6 +29,7 @@
 import jakarta.persistence.criteria.From;
 import jakarta.persistence.criteria.Join;
 import jakarta.persistence.criteria.JoinType;
+import jakarta.persistence.criteria.Nulls;
 import jakarta.persistence.criteria.Path;
 import jakarta.persistence.metamodel.Attribute;
 import jakarta.persistence.metamodel.Attribute.PersistentAttributeType;
@@ -292,9 +293,8 @@ public static String applySorting(String query, Sort sort, @Nullable String alia
 		Set<String> selectionAliases = getFunctionAliases(query);
 		selectionAliases.addAll(getFieldAliases(query));
 
-		String orderClauses = sort.stream()
-			.map(order -> getOrderClause(joinAliases, selectionAliases, alias, order))
-			.collect(Collectors.joining(", "));
+		String orderClauses = sort.stream().map(order -> getOrderClause(joinAliases, selectionAliases, alias, order))
+				.collect(Collectors.joining(", "));
 
 		builder.append(orderClauses);
 
@@ -753,18 +753,25 @@ private static jakarta.persistence.criteria.Order toJpaOrder(Order order, From<?
 		PropertyPath property = PropertyPath.from(order.getProperty(), from.getJavaType());
 		Expression<?> expression = toExpressionRecursively(from, property);
 
-		if (order.getNullHandling() != Sort.NullHandling.NATIVE) {
-			throw new UnsupportedOperationException("Applying Null Precedence using Criteria Queries is not yet supported.");
-		}
+		Nulls nulls = toNulls(order.getNullHandling());
 
 		if (order.isIgnoreCase() && String.class.equals(expression.getJavaType())) {
 			Expression<String> upper = cb.lower((Expression<String>) expression);
-			return order.isAscending() ? cb.asc(upper) : cb.desc(upper);
+			return order.isAscending() ? cb.asc(upper, nulls) : cb.desc(upper, nulls);
 		} else {
-			return order.isAscending() ? cb.asc(expression) : cb.desc(expression);
+			return order.isAscending() ? cb.asc(expression, nulls) : cb.desc(expression, nulls);
 		}
 	}
 
+	private static Nulls toNulls(Sort.NullHandling nullHandling) {
+
+		return switch (nullHandling) {
+			case NULLS_LAST -> Nulls.LAST;
+			case NULLS_FIRST -> Nulls.FIRST;
+			case NATIVE -> Nulls.NONE;
+		};
+	}
+
 	static <T> Expression<T> toExpressionRecursively(From<?, ?> from, PropertyPath property) {
 		return toExpressionRecursively(from, property, false);
 	}
diff --git a/spring-data-jpa/src/test/java/org/springframework/data/jpa/repository/query/QueryUtilsIntegrationTests.java b/spring-data-jpa/src/test/java/org/springframework/data/jpa/repository/query/QueryUtilsIntegrationTests.java
index 59eb5f8667..1c7adc781d 100644
--- a/spring-data-jpa/src/test/java/org/springframework/data/jpa/repository/query/QueryUtilsIntegrationTests.java
+++ b/spring-data-jpa/src/test/java/org/springframework/data/jpa/repository/query/QueryUtilsIntegrationTests.java
@@ -32,6 +32,7 @@
 import jakarta.persistence.criteria.From;
 import jakarta.persistence.criteria.Join;
 import jakarta.persistence.criteria.JoinType;
+import jakarta.persistence.criteria.Nulls;
 import jakarta.persistence.criteria.Root;
 import jakarta.persistence.spi.PersistenceProvider;
 import jakarta.persistence.spi.PersistenceProviderResolver;
@@ -314,8 +315,8 @@ void toOrdersCanSortByJoinColumn() {
 		assertThat(orders).hasSize(1);
 	}
 
-	@Test // GH-3529
-	void nullPrecedenceThroughCriteriaApiNotYetSupported() {
+	@Test // GH-3529, GH-3587
+	void queryUtilsConsidersNullPrecedence() {
 
 		CriteriaBuilder builder = em.getCriteriaBuilder();
 		CriteriaQuery<User> query = builder.createQuery(User.class);
@@ -324,8 +325,10 @@ void nullPrecedenceThroughCriteriaApiNotYetSupported() {
 
 		Sort sort = Sort.by(Sort.Order.desc("manager").nullsFirst());
 
-		assertThatExceptionOfType(UnsupportedOperationException.class)
-				.isThrownBy(() -> QueryUtils.toOrders(sort, join, builder));
+		List<jakarta.persistence.criteria.Order> orders = QueryUtils.toOrders(sort, join, builder);
+		for (jakarta.persistence.criteria.Order order : orders) {
+			assertThat(order.getNullPrecedence()).isEqualTo(Nulls.FIRST);
+		}
 	}
 
 	/**