8179918: EnumSet spliterator should report SORTED, ORDERED, NONNULL

Reviewed-by: vklang

Author: kilink

src/java.base/share/classes/java/util/EnumSet.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2025, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -501,4 +501,10 @@ private void readObjectNoData()
         throws java.io.InvalidObjectException {
         throw new java.io.InvalidObjectException("Proxy required");
     }
+
+    @Override
+    public Spliterator<E> spliterator() {
+        return Spliterators.spliterator(this,
+                Spliterator.DISTINCT | Spliterator.SORTED | Spliterator.ORDERED | Spliterator.NONNULL);
+    }
 }

test/jdk/java/util/EnumSet/EnumSetSpliteratorTest.java

@@ -0,0 +1,97 @@
+/*
+ * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/*
+ * @test
+ * @run     junit EnumSetSpliteratorTest
+ * @bug     8179918
+ * @summary EnumSet spliterator should report SORTED, ORDERED, NONNULL
+ */
+
+import java.util.EnumSet;
+import java.util.List;
+import java.util.Spliterator;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+public class EnumSetSpliteratorTest {
+
+    private enum Empty {}
+
+    private enum Small {
+        a, b, c, d
+    }
+
+    private enum Large {
+        e00, e01, e02, e03, e04, e05, e06, e07,
+        e08, e09, e0A, e0B, e0C, e0D, e0E, e0F,
+        e10, e11, e12, e13, e14, e15, e16, e17,
+        e18, e19, e1A, e1B, e1C, e1D, e1E, e1F,
+        e20, e21, e22, e23, e24, e25, e26, e27,
+        e28, e29, e2A, e2B, e2C, e2D, e2E, e2F,
+        e30, e31, e32, e33, e34, e35, e36, e37,
+        e38, e39, e3A, e3B, e3C, e3D, e3E, e3F,
+        e40, e41, e42, e43, e44, e45, e46, e47,
+        e48, e49, e4A, e4B, e4C, e4D, e4E, e4F
+    }
+
+    @Test
+    public void testSpliteratorCharacteristics() {
+        assertSpliteratorCharacteristics(EnumSet.allOf(Empty.class));
+        assertSpliteratorCharacteristics(EnumSet.allOf(Small.class));
+        assertSpliteratorCharacteristics(EnumSet.allOf(Large.class));
+        assertSpliteratorCharacteristics(EnumSet.noneOf(Empty.class));
+        assertSpliteratorCharacteristics(EnumSet.noneOf(Small.class));
+        assertSpliteratorCharacteristics(EnumSet.noneOf(Large.class));
+        assertSpliteratorCharacteristics(EnumSet.of(Small.a, Small.d));
+        assertSpliteratorCharacteristics(EnumSet.range(Small.a, Small.c));
+        assertSpliteratorCharacteristics(EnumSet.range(Large.e02, Large.e4D));
+        assertSpliteratorCharacteristics(EnumSet.complementOf(EnumSet.of(Small.c)));
+        assertSpliteratorCharacteristics(EnumSet.complementOf(EnumSet.of(Large.e00, Large.e4F)));
+    }
+
+    @Test
+    public void testEncounterOrder() {
+        assertEquals(List.of(Small.values()), EnumSet.allOf(Small.class).stream().toList());
+        assertEquals(List.of(Large.values()), EnumSet.allOf(Large.class).stream().toList());
+    }
+
+    private static final int EXPECTED_CHARACTERISTICS = (
+            Spliterator.DISTINCT | Spliterator.SORTED | Spliterator.ORDERED |
+                    Spliterator.NONNULL | Spliterator.SIZED | Spliterator.SUBSIZED);
+
+    private static void assertSpliteratorCharacteristics(EnumSet<?> enumSet) {
+        Spliterator<?> spliterator = enumSet.spliterator();
+        assertTrue(spliterator.hasCharacteristics(Spliterator.DISTINCT), "Missing DISTINCT");
+        assertTrue(spliterator.hasCharacteristics(Spliterator.SORTED), "Missing SORTED");
+        assertTrue(spliterator.hasCharacteristics(Spliterator.ORDERED), "Missing ORDERED");
+        assertTrue(spliterator.hasCharacteristics(Spliterator.NONNULL), "Missing NONNULL");
+        assertTrue(spliterator.hasCharacteristics(Spliterator.SIZED), "Missing SIZED");
+        assertTrue(spliterator.hasCharacteristics(Spliterator.SUBSIZED), "Missing SUBSIZED");
+        assertEquals(EXPECTED_CHARACTERISTICS, spliterator.characteristics(), "Unexpected characteristics");
+    }
+}