Retain case-sensitivity and null-handling when changing Sort direction.

We now retain case-sensitivity and null-handling configuration when changing the entire Sort direction.

Closes #2585

Author: mp911de

Diff for: src/main/java/org/springframework/data/domain/Sort.java

@@ -259,7 +259,7 @@ public String toString() {
 	 */
 	private Sort withDirection(Direction direction) {
 
-		return Sort.by(stream().map(it -> new Order(direction, it.getProperty())).collect(Collectors.toList()));
+		return Sort.by(stream().map(it -> it.with(direction)).collect(Collectors.toList()));
 	}
 
 	/**

Diff for: src/test/java/org/springframework/data/domain/SortUnitTests.java

@@ -104,9 +104,12 @@ void handlesAdditionalNullSort() {
 		assertThat(sort).containsExactly(Order.by("foo"));
 	}
 
-	@Test // DATACMNS-281, DATACMNS-1021
+	@Test // DATACMNS-281, DATACMNS-1021, GH-2585
 	void configuresIgnoreCaseForOrder() {
+
 		assertThat(Order.asc("foo").ignoreCase().isIgnoreCase()).isTrue();
+		assertThat(Sort.by(Order.by("foo").ignoreCase()).descending().iterator().next().isIgnoreCase()).isTrue();
+		assertThat(Sort.by(Order.by("foo").ignoreCase()).ascending().iterator().next().isIgnoreCase()).isTrue();
 	}
 
 	@Test // DATACMNS-281, DATACMNS-1021
@@ -154,6 +157,15 @@ void orderWithDefaultNullHandlingHint() {
 		assertThat(Order.by("foo").getNullHandling()).isEqualTo(NATIVE);
 	}
 
+	@Test // GH-2585
+	void retainsNullHandlingAfterChangingDirection() {
+
+		assertThat(Sort.by(Order.by("foo").with(NULLS_FIRST)).ascending().iterator().next().getNullHandling())
+				.isEqualTo(NULLS_FIRST);
+		assertThat(Sort.by(Order.by("foo").with(NULLS_FIRST)).descending().iterator().next().getNullHandling())
+				.isEqualTo(NULLS_FIRST);
+	}
+
 	@Test // DATACMNS-908
 	void createsNewOrderForDifferentProperty() {