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8171826: Comparator.reverseOrder(c) mishandles singleton comparators

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Reviewed-by: rriggs
This commit is contained in:
Paul Sandoz 2017-12-12 09:33:35 -08:00
parent f1212e26c3
commit 72e7a31529
2 changed files with 46 additions and 16 deletions
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24
src/java.base/share/classes/java/util/Collections.java
View File

@ -24,9 +24,10 @@
*/
package java.util;
import java.io.Serializable;
import java.io.ObjectOutputStream;
import java.io.IOException;
import java.io.ObjectOutputStream;
import java.io.Serializable;
import java.lang.reflect.Array;
import java.util.function.BiConsumer;
import java.util.function.BiFunction;
@ -5164,14 +5165,19 @@ public class Collections {
* specified comparator.
* @since 1.5
*/
@SuppressWarnings("unchecked")
public static <T> Comparator<T> reverseOrder(Comparator<T> cmp) {
if (cmp == null)
return reverseOrder();
if (cmp instanceof ReverseComparator2)
return ((ReverseComparator2<T>)cmp).cmp;
return new ReverseComparator2<>(cmp);
if (cmp == null) {
return (Comparator<T>) ReverseComparator.REVERSE_ORDER;
} else if (cmp == ReverseComparator.REVERSE_ORDER) {
return (Comparator<T>) Comparators.NaturalOrderComparator.INSTANCE;
} else if (cmp == Comparators.NaturalOrderComparator.INSTANCE) {
return (Comparator<T>) ReverseComparator.REVERSE_ORDER;
} else if (cmp instanceof ReverseComparator2) {
return ((ReverseComparator2<T>) cmp).cmp;
} else {
return new ReverseComparator2<>(cmp);
}
}
/**

38
test/jdk/java/util/Comparator/BasicTest.java
View File

@ -1,5 +1,5 @@
/*
* Copyright (c) 2013, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2013, 2017 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
@ -23,22 +23,21 @@
/**
* @test
* @bug 8171826
* @summary Comparator default method tests
* @run testng BasicTest
*/
import java.util.TreeMap;
import java.util.Comparator;
import org.testng.annotations.Test;
import java.util.Collections;
import java.util.Comparator;
import java.util.function.Function;
import java.util.function.ToDoubleFunction;
import java.util.function.ToIntFunction;
import java.util.function.ToLongFunction;
import java.util.function.ToDoubleFunction;
import static org.testng.Assert.assertEquals;
import static org.testng.Assert.assertTrue;
import static org.testng.Assert.fail;
import static org.testng.Assert.*;
@Test(groups = "unit")
public class BasicTest {
@ -366,4 +365,29 @@ public class BasicTest {
fail("comparing(null) should throw NPE");
} catch (NullPointerException npe) {}
}
public void testNaturalAndReverseIdentity() {
var naturalOrder = Comparator.<String>naturalOrder();
var reverseOrder = Comparator.<String>reverseOrder();
assertEquals(
naturalOrder,
Collections.reverseOrder(reverseOrder),
"Comparator.naturalOrder() and Collections.reverseOrder(Comparator.reverseOrder()) not equal");
assertEquals(
reverseOrder,
Collections.reverseOrder(naturalOrder),
"Comparator.reverseOrder() and Collections.reverseOrder(Comparator.naturalOrder()) not equal");
assertEquals(
naturalOrder.reversed(),
reverseOrder,
"Comparator.naturalOrder().reversed() amd Comparator.reverseOrder() not equal");
assertEquals(
reverseOrder.reversed(),
naturalOrder,
"Comparator.reverseOrder().reversed() and Comparator.naturalOrder() not equal");
}
}