8017447: Unmodifiable map entry becomes modifiable if taken from a stream of map entries

Reviewed-by: briangoetz

src/share/classes/java/util/Collections.java

@@ -34,6 +34,8 @@ import java.util.function.Consumer;
 import java.util.function.Function;
 import java.util.function.Predicate;
 import java.util.function.UnaryOperator;
+import java.util.stream.Stream;
+import java.util.stream.StreamSupport;
 
 /**
  * This class consists exclusively of static methods that operate on or return
@@ -1510,6 +1512,86 @@ public class Collections {
                 // Need to cast to raw in order to work around a limitation in the type system
                 super((Set)s);
             }
+
+            static <K, V> Consumer<Map.Entry<K, V>> entryConsumer(Consumer<? super Entry<K, V>> action) {
+                return e -> action.accept(new UnmodifiableEntry<>(e));
+            }
+
+            public void forEach(Consumer<? super Entry<K, V>> action) {
+                Objects.requireNonNull(action);
+                c.forEach(entryConsumer(action));
+            }
+
+            static final class UnmodifiableEntrySetSpliterator<K, V>
+                    implements Spliterator<Entry<K,V>> {
+                final Spliterator<Map.Entry<K, V>> s;
+
+                UnmodifiableEntrySetSpliterator(Spliterator<Entry<K, V>> s) {
+                    this.s = s;
+                }
+
+                @Override
+                public boolean tryAdvance(Consumer<? super Entry<K, V>> action) {
+                    Objects.requireNonNull(action);
+                    return s.tryAdvance(entryConsumer(action));
+                }
+
+                @Override
+                public void forEachRemaining(Consumer<? super Entry<K, V>> action) {
+                    Objects.requireNonNull(action);
+                    s.forEachRemaining(entryConsumer(action));
+                }
+
+                @Override
+                public Spliterator<Entry<K, V>> trySplit() {
+                    Spliterator<Entry<K, V>> split = s.trySplit();
+                    return split == null
+                           ? null
+                           : new UnmodifiableEntrySetSpliterator<>(split);
+                }
+
+                @Override
+                public long estimateSize() {
+                    return s.estimateSize();
+                }
+
+                @Override
+                public long getExactSizeIfKnown() {
+                    return s.getExactSizeIfKnown();
+                }
+
+                @Override
+                public int characteristics() {
+                    return s.characteristics();
+                }
+
+                @Override
+                public boolean hasCharacteristics(int characteristics) {
+                    return s.hasCharacteristics(characteristics);
+                }
+
+                @Override
+                public Comparator<? super Entry<K, V>> getComparator() {
+                    return s.getComparator();
+                }
+            }
+
+            @SuppressWarnings("unchecked")
+            public Spliterator<Entry<K,V>> spliterator() {
+                return new UnmodifiableEntrySetSpliterator<>(
+                        (Spliterator<Map.Entry<K, V>>) c.spliterator());
+            }
+
+            @Override
+            public Stream<Entry<K,V>> stream() {
+                return StreamSupport.stream(spliterator());
+            }
+
+            @Override
+            public Stream<Entry<K,V>> parallelStream() {
+                return StreamSupport.parallelStream(spliterator());
+            }
+
             public Iterator<Map.Entry<K,V>> iterator() {
                 return new Iterator<Map.Entry<K,V>>() {
                     private final Iterator<? extends Map.Entry<? extends K, ? extends V>> i = c.iterator();

test/java/util/Collections/UnmodifiableMapEntrySet.java

+/*
+ * Copyright (c) 2013, 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 testng UnmodifiableMapEntrySet
+ * @summary Unit tests for wrapping classes should delegate to default methods
+ */
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Spliterator;
+import java.util.TreeMap;
+import java.util.function.Consumer;
+import java.util.function.Function;
+import java.util.function.Supplier;
+
+import org.testng.annotations.Test;
+import org.testng.annotations.DataProvider;
+
+import static org.testng.Assert.assertEquals;
+
+@Test(groups = "unit")
+public class UnmodifiableMapEntrySet {
+    static Object[][] collections;
+
+    static <M extends Map<Integer, Integer>> M fillMap(int size, M m) {
+        for (int i = 0; i < size; i++) {
+            m.put(i, i);
+        }
+        return m;
+    }
+
+    @DataProvider(name="maps")
+    static Object[][] mapCases() {
+        if (collections != null) {
+            return collections;
+        }
+
+        List<Object[]> cases = new ArrayList<>();
+        for (int size : new int[] {1, 2, 16}) {
+            cases.add(new Object[] {
+                    String.format("new HashMap(%d)", size),
+                    (Supplier<Map<Integer, Integer>>)
+                    () -> Collections.unmodifiableMap(fillMap(size, new HashMap<>())) });
+            cases.add(new Object[] {
+                    String.format("new TreeMap(%d)", size),
+                    (Supplier<Map<Integer, Integer>>)
+                    () -> Collections.unmodifiableSortedMap(fillMap(size, new TreeMap<>())) });
+        }
+
+        return cases.toArray(new Object[0][]);
+    }
+
+    static class EntryConsumer implements Consumer<Map.Entry<Integer, Integer>> {
+        int updates;
+        @Override
+        public void accept(Map.Entry<Integer, Integer> me) {
+            try {
+                me.setValue(Integer.MAX_VALUE);
+                updates++;
+            } catch (UnsupportedOperationException e) {
+            }
+        }
+
+        void assertNoUpdates() {
+            assertEquals(updates, 0, "Updates to entries");
+        }
+    }
+
+    void testWithEntryConsumer(Consumer<EntryConsumer> c) {
+        EntryConsumer ec = new EntryConsumer();
+        c.accept(ec);
+        ec.assertNoUpdates();
+    }
+
+    @Test(dataProvider = "maps")
+    public void testForEach(String d, Supplier<Map<Integer, Integer>> ms) {
+        testWithEntryConsumer(
+                ec -> ms.get().entrySet().forEach(ec));
+    }
+
+    @Test(dataProvider = "maps")
+    public void testIteratorForEachRemaining(String d, Supplier<Map<Integer, Integer>> ms) {
+        testWithEntryConsumer(
+                ec -> ms.get().entrySet().iterator().forEachRemaining(ec));
+    }
+
+    @Test(dataProvider = "maps")
+    public void testIteratorNext(String d, Supplier<Map<Integer, Integer>> ms) {
+        testWithEntryConsumer(ec -> {
+            for (Map.Entry<Integer, Integer> me : ms.get().entrySet()) {
+                ec.accept(me);
+            }
+        });
+    }
+
+    @Test(dataProvider = "maps")
+    public void testSpliteratorForEachRemaining(String d, Supplier<Map<Integer, Integer>> ms) {
+        testSpliterator(
+                ms.get().entrySet()::spliterator,
+                // Higher order function returning a consumer that
+                // traverses all spliterator elements using an EntryConsumer
+                s -> ec -> s.forEachRemaining(ec));
+    }
+
+    @Test(dataProvider = "maps")
+    public void testSpliteratorTryAdvance(String d, Supplier<Map<Integer, Integer>> ms) {
+        testSpliterator(
+                ms.get().entrySet()::spliterator,
+                // Higher order function returning a consumer that
+                // traverses all spliterator elements using an EntryConsumer
+                s -> ec -> { while (s.tryAdvance(ec)); });
+    }
+
+    void testSpliterator(Supplier<Spliterator<Map.Entry<Integer, Integer>>> ss,
+                         // Higher order function that given a spliterator returns a
+                         // consumer for that spliterator which traverses elements
+                         // using an EntryConsumer
+                         Function<Spliterator<Map.Entry<Integer, Integer>>, Consumer<EntryConsumer>> sc) {
+        testWithEntryConsumer(sc.apply(ss.get()));
+
+        Spliterator<Map.Entry<Integer, Integer>> s = ss.get();
+        Spliterator<Map.Entry<Integer, Integer>> split = s.trySplit();
+        if (split != null) {
+            testWithEntryConsumer(sc.apply(split));
+            testWithEntryConsumer(sc.apply(s));
+        }
+    }
+
+    @Test(dataProvider = "maps")
+    public void testStreamForEach(String d, Supplier<Map<Integer, Integer>> ms) {
+        testWithEntryConsumer(ec -> ms.get().entrySet().stream().forEach(ec));
+    }
+
+    @Test(dataProvider = "maps")
+    public void testParallelStreamForEach(String d, Supplier<Map<Integer, Integer>> ms) {
+        testWithEntryConsumer(ec -> ms.get().entrySet().parallelStream().forEach(ec));
+    }
+}
+