Allow combining Sort and TypedSort using Sort.and(…).

We now retain properly the collection of orders by using accessor methods instead of relying on using the orders field. TypedSort orders are not using the orders field, instead they iterate over recorded persistent property paths.

Closes spring-projects#2103
Original pull request: spring-projects#2377.

Author: mp911de

src/main/java/org/springframework/data/domain/Sort.java

@@ -170,7 +170,7 @@ public Sort ascending() {
 	}
 
 	public boolean isSorted() {
-		return !orders.isEmpty();
+		return !isEmpty();
 	}
 
 	public boolean isUnsorted() {
@@ -188,7 +188,7 @@ public Sort and(Sort sort) {
 
 		Assert.notNull(sort, "Sort must not be null!");
 
-		ArrayList<Order> these = new ArrayList<>(this.orders);
+		ArrayList<Order> these = new ArrayList<>(this.toList());
 
 		for (Order order : sort) {
 			these.add(order);
@@ -240,7 +240,7 @@ public boolean equals(@Nullable Object obj) {
 
 		Sort that = (Sort) obj;
 
-		return this.orders.equals(that.orders);
+		return toList().equals(that.toList());
 	}
 
 	/*
@@ -261,7 +261,7 @@ public int hashCode() {
 	 */
 	@Override
 	public String toString() {
-		return orders.isEmpty() ? "UNSORTED" : StringUtils.collectionToCommaDelimitedString(orders);
+		return isEmpty() ? "UNSORTED" : StringUtils.collectionToCommaDelimitedString(orders);
 	}
 
 	/**
@@ -272,7 +272,7 @@ public String toString() {
 	 */
 	private Sort withDirection(Direction direction) {
 
-		return Sort.by(orders.stream().map(it -> new Order(direction, it.getProperty())).collect(Collectors.toList()));
+		return Sort.by(stream().map(it -> new Order(direction, it.getProperty())).collect(Collectors.toList()));
 	}
 
 	/**

src/test/java/org/springframework/data/domain/SortUnitTests.java

@@ -25,6 +25,7 @@
 import org.junit.jupiter.api.Test;
 import org.springframework.data.domain.Sort.Direction;
 import org.springframework.data.domain.Sort.Order;
+import org.springframework.data.geo.Circle;
 
 /**
  * Unit test for {@link Sort}.
@@ -33,6 +34,7 @@
  * @author Kevin Raymond
  * @author Thomas Darimont
  * @author Mark Paluch
+ * @author Hiufung Kwok
  */
 class SortUnitTests {
 
@@ -186,6 +188,17 @@ void translatesTypedSortCorrectly() {
 				.containsExactly(Order.by("nesteds.firstname"));
 	}
 
+	@Test // #2103
+	void allowsCombiningTypedSorts() {
+
+		assertThat(Sort.sort(Circle.class).by(Circle::getCenter) //
+				.and(Sort.sort(Circle.class).by(Circle::getRadius))) //
+						.containsExactly(Order.by("center"), Order.by("radius"));
+
+		assertThat(Sort.by("center").and(Sort.sort(Circle.class).by(Circle::getRadius))) //
+				.containsExactly(Order.by("center"), Order.by("radius"));
+	}
+
 	@Getter
 	static class Sample {
 		Nested nested;