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1 /*
2  * Copyright (c) 2018 Google Inc. All rights reserved.
3  * Copyright (c) 2018, 2022, Oracle and/or its affiliates. All rights reserved.
4  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
5  *
6  * This code is free software; you can redistribute it and/or modify it
7  * under the terms of the GNU General Public License version 2 only, as
8  * published by the Free Software Foundation.
9  *
10  * This code is distributed in the hope that it will be useful, but WITHOUT
11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
13  * version 2 for more details (a copy is included in the LICENSE file that
14  * accompanied this code).
15  *
16  * You should have received a copy of the GNU General Public License version
17  * 2 along with this work; if not, write to the Free Software Foundation,
18  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
19  *
20  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
21  * or visit www.oracle.com if you need additional information or have any
22  * questions.
23  */
24 
25 /*
26  * @test
27  * @run junit DelegatingIteratorForEachRemaining
28  */
29 
30 package test.java.util.Collections;
31 
32 import org.junit.Assert;
33 import org.junit.Test;
34 
35 import java.util.Collection;
36 import java.util.Collections;
37 import java.util.HashMap;
38 import java.util.Iterator;
39 import java.util.Map;
40 import java.util.Objects;
41 import java.util.Set;
42 import java.util.Spliterator;
43 import java.util.function.BiConsumer;
44 import java.util.function.BiFunction;
45 import java.util.function.Consumer;
46 import java.util.function.Function;
47 import java.util.function.Predicate;
48 import java.util.stream.Stream;
49 
50 public class DelegatingIteratorForEachRemaining {
51 
52     static abstract class ForwardingIterator<E> implements Iterator<E> {
53         private final Iterator<E> delegate;
54 
ForwardingIterator(Iterator<E> delegate)55         protected ForwardingIterator(Iterator<E> delegate) {
56             this.delegate = Objects.requireNonNull(delegate);
57         }
58 
hasNext()59         @Override public boolean hasNext() { return delegate.hasNext(); }
next()60         @Override public E next() { return delegate.next(); }
remove()61         @Override public void remove() { delegate.remove(); }
forEachRemaining(Consumer<? super E> action)62         @Override public void forEachRemaining(Consumer<? super E> action) {
63             delegate.forEachRemaining(action);
64         }
65     }
66 
67     static final class ThrowingIterator<E> extends ForwardingIterator<E> {
ThrowingIterator(Iterator<E> delegate)68         public ThrowingIterator(Iterator<E> delegate) {
69             super(delegate);
70         }
71 
72         @Override
forEachRemaining(Consumer<? super E> action)73         public void forEachRemaining(Consumer<? super E> action) {
74             throw new UnsupportedOperationException();
75         }
76     }
77 
78     static abstract class ForwardingSet<E> implements Set<E> {
79         private final Set<E> delegate;
80 
ForwardingSet(Set<E> delegate)81         protected ForwardingSet(Set<E> delegate) {
82             this.delegate = Objects.requireNonNull(delegate);
83         }
84 
size()85         @Override public int size() { return delegate.size(); }
isEmpty()86         @Override public boolean isEmpty() { return delegate.isEmpty(); }
contains(Object o)87         @Override public boolean contains(Object o) { return delegate.contains(o); }
iterator()88         @Override public Iterator<E> iterator() { return delegate.iterator(); }
toArray()89         @Override public Object[] toArray() { return delegate.toArray(); }
toArray( T[] ts)90         @Override public <T> T[] toArray( T[] ts) { return delegate.toArray(ts); }
add(E e)91         @Override public boolean add(E e) { return delegate.add(e); }
remove(Object o)92         @Override public boolean remove(Object o) { return delegate.remove(o); }
containsAll( Collection<?> c)93         @Override public boolean containsAll( Collection<?> c) { return delegate.containsAll(c); }
addAll( Collection<? extends E> c)94         @Override public boolean addAll( Collection<? extends E> c) { return delegate.addAll(c); }
retainAll( Collection<?> c)95         @Override public boolean retainAll( Collection<?> c) { return delegate.retainAll(c); }
removeAll( Collection<?> c)96         @Override public boolean removeAll( Collection<?> c) { return delegate.removeAll(c); }
clear()97         @Override public void clear() { delegate.clear(); }
equals(Object o)98         @Override public boolean equals(Object o) { return delegate.equals(o); }
hashCode()99         @Override public int hashCode() { return delegate.hashCode(); }
spliterator()100         @Override public Spliterator<E> spliterator() { return delegate.spliterator(); }
removeIf(Predicate<? super E> filter)101         @Override public boolean removeIf(Predicate<? super E> filter) { return delegate.removeIf(filter); }
stream()102         @Override public Stream<E> stream() { return delegate.stream(); }
parallelStream()103         @Override public Stream<E> parallelStream() { return delegate.parallelStream(); }
forEach(Consumer<? super E> action)104         @Override public void forEach(Consumer<? super E> action) { delegate.forEach(action); }
105     }
106 
107     static class ThrowingSet<E> extends ForwardingSet<E> {
ThrowingSet(Set<E> delegate)108         public ThrowingSet(Set<E> delegate) {
109             super(delegate);
110         }
111 
112         @Override
iterator()113         public ThrowingIterator<E> iterator() {
114             return new ThrowingIterator<>(super.iterator());
115         }
116     }
117 
118     static abstract class ForwardingMap<K, V> implements Map<K, V> {
119         private final Map<K, V> delegate;
120 
ForwardingMap(Map<K, V> delegate)121         public ForwardingMap(Map<K, V> delegate) {
122             this.delegate = delegate;
123         }
124 
size()125         @Override public int size() { return delegate.size(); }
isEmpty()126         @Override public boolean isEmpty() { return delegate.isEmpty(); }
containsKey(Object o)127         @Override public boolean containsKey(Object o) { return delegate.containsKey(o); }
containsValue(Object o)128         @Override public boolean containsValue(Object o) { return delegate.containsValue(o); }
get(Object o)129         @Override public V get(Object o) { return delegate.get(o); }
put(K k, V v)130         @Override public V put(K k, V v) { return delegate.put(k, v); }
remove(Object o)131         @Override public V remove(Object o) { return delegate.remove(o); }
putAll(Map<? extends K, ? extends V> map)132         @Override public void putAll(Map<? extends K, ? extends V> map) { delegate.putAll(map); }
clear()133         @Override public void clear() { delegate.clear(); }
keySet()134         @Override public Set<K> keySet() { return delegate.keySet(); }
values()135         @Override public Collection<V> values() { return delegate.values(); }
entrySet()136         @Override public Set<Entry<K, V>> entrySet() { return delegate.entrySet(); }
equals(Object o)137         @Override public boolean equals(Object o) { return delegate.equals(o); }
hashCode()138         @Override public int hashCode() { return delegate.hashCode(); }
getOrDefault(Object key, V defaultValue)139         @Override public V getOrDefault(Object key, V defaultValue) { return delegate.getOrDefault(key, defaultValue); }
forEach(BiConsumer<? super K, ? super V> action)140         @Override public void forEach(BiConsumer<? super K, ? super V> action) { delegate.forEach(action); }
replaceAll(BiFunction<? super K, ? super V, ? extends V> function)141         @Override public void replaceAll(BiFunction<? super K, ? super V, ? extends V> function) { delegate.replaceAll(function); }
putIfAbsent(K key, V value)142         @Override public V putIfAbsent(K key, V value) { return delegate.putIfAbsent(key, value); }
remove(Object key, Object value)143         @Override public boolean remove(Object key, Object value) { return delegate.remove(key, value); }
replace(K key, V oldValue, V newValue)144         @Override public boolean replace(K key, V oldValue, V newValue) { return delegate.replace(key, oldValue, newValue); }
replace(K key, V value)145         @Override public V replace(K key, V value) { return delegate.replace(key, value); }
computeIfAbsent(K key, Function<? super K, ? extends V> mappingFunction)146         @Override public V computeIfAbsent(K key, Function<? super K, ? extends V> mappingFunction) { return delegate.computeIfAbsent(key, mappingFunction); }
computeIfPresent(K key, BiFunction<? super K, ? super V, ? extends V> remappingFunction)147         @Override public V computeIfPresent(K key, BiFunction<? super K, ? super V, ? extends V> remappingFunction) { return delegate.computeIfPresent(key, remappingFunction); }
compute(K key, BiFunction<? super K, ? super V, ? extends V> remappingFunction)148         @Override public V compute(K key, BiFunction<? super K, ? super V, ? extends V> remappingFunction) { return delegate.compute(key, remappingFunction); }
merge(K key, V value, BiFunction<? super V, ? super V, ? extends V> remappingFunction)149         @Override public V merge(K key, V value, BiFunction<? super V, ? super V, ? extends V> remappingFunction) { return delegate.merge(key, value, remappingFunction); }
150     }
151 
152     static class ThrowingMap<K, V> extends ForwardingMap<K, V> {
ThrowingMap(Map<K, V> delegate)153         public ThrowingMap(Map<K, V> delegate) {
154             super(delegate);
155         }
156 
157         @Override
entrySet()158         public ThrowingSet<Entry<K, V>> entrySet() {
159             return new ThrowingSet<>(super.entrySet());
160         }
161 
162         @Override
keySet()163         public Set<K> keySet() {
164             return new ThrowingSet(super.keySet());
165         }
166     }
167 
assertThrowingIterator(Iterator<E> iterator)168     static<E> void assertThrowingIterator(Iterator<E> iterator) {
169         try {
170             iterator.forEachRemaining((entry) -> {});
171             Assert.fail();
172         } catch (UnsupportedOperationException expected) {
173         }
174     }
175 
map()176     private static Map<String, Object> map() {
177         Map<String, Object> map = new HashMap<>();
178         map.put("name", "Bill");
179         map.put("age", 23);
180         return new ThrowingMap<>(map);
181     }
182 
testUnwrapped()183     @Test public void testUnwrapped() {
184         assertThrowingIterator(map().entrySet().iterator());
185         assertThrowingIterator(map().keySet().iterator());
186     }
187 
test_unmodifiableMap_entrySet()188     @Test public void test_unmodifiableMap_entrySet() {
189         assertThrowingIterator(Collections.unmodifiableMap(map()).entrySet().iterator());
190     }
191 
test_checkedMap_entrySet()192     @Test public void test_checkedMap_entrySet() {
193         assertThrowingIterator(Collections.checkedMap(map(), String.class, Object.class).entrySet().iterator());
194     }
195 
test_entrySet_checkedSet()196     @Test public void test_entrySet_checkedSet() {
197         Set<Map.Entry<String, Object>> entrySet = map().entrySet();
198         Class clazz = entrySet.iterator().next().getClass();
199         assertThrowingIterator(Collections.checkedSet(entrySet, clazz).iterator());
200     }
201 
202     /**
203      * Calls Collections.unmodifiableMap().entrySet().iterator().forEachRemaining() by passing
204      * that method a {@code null} action and expects that call to fail with a
205      * {@code NullPointerException}.
206      */
207     @Test
testUnmodifiableForEachRemainingNPE()208     public void testUnmodifiableForEachRemainingNPE() {
209         final Iterator<?> it = Collections.unmodifiableMap(Map.of()).entrySet().iterator();
210         // pass null action and expect a NPE
211         Assert.assertThrows(NullPointerException.class, () -> it.forEachRemaining(null));
212     }
213 
214     /**
215      * Calls Collections.checkedMap().entrySet().iterator().forEachRemaining() by passing
216      * that method a {@code null} action and expects that call to fail with a
217      * {@code NullPointerException}.
218      */
219     @Test
testCheckedMapForEachRemainingNPE()220     public void testCheckedMapForEachRemainingNPE() {
221         final Iterator<?> it = Collections.checkedMap(Map.of(), String.class,
222                 String.class).entrySet().iterator();
223         // pass null "action" and expect it to fail with NPE
224         Assert.assertThrows(NullPointerException.class, () -> it.forEachRemaining(null));
225     }
226 }
227