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1   /*
2    * Copyright (C) 2008 The Guava Authors
3    *
4    * Licensed under the Apache License, Version 2.0 (the "License");
5    * you may not use this file except in compliance with the License.
6    * You may obtain a copy of the License at
7    *
8    * http://www.apache.org/licenses/LICENSE-2.0
9    *
10   * Unless required by applicable law or agreed to in writing, software
11   * distributed under the License is distributed on an "AS IS" BASIS,
12   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13   * See the License for the specific language governing permissions and
14   * limitations under the License.
15   */
16  
17  package com.google.common.collect.testing.testers;
18  
19  import static com.google.common.collect.testing.features.CollectionSize.SEVERAL;
20  import static com.google.common.collect.testing.features.CollectionSize.ZERO;
21  import static com.google.common.collect.testing.features.MapFeature.ALLOWS_NULL_KEYS;
22  import static com.google.common.collect.testing.features.MapFeature.ALLOWS_NULL_KEY_QUERIES;
23  import static com.google.common.collect.testing.features.MapFeature.FAILS_FAST_ON_CONCURRENT_MODIFICATION;
24  import static com.google.common.collect.testing.features.MapFeature.SUPPORTS_REMOVE;
25  
26  import com.google.common.annotations.GwtCompatible;
27  import com.google.common.collect.testing.AbstractMapTester;
28  import com.google.common.collect.testing.WrongType;
29  import com.google.common.collect.testing.features.CollectionSize;
30  import com.google.common.collect.testing.features.MapFeature;
31  import java.util.ConcurrentModificationException;
32  import java.util.Iterator;
33  import java.util.Map.Entry;
34  
35  /**
36   * A generic JUnit test which tests {@code remove} operations on a map. Can't be
37   * invoked directly; please see
38   * {@link com.google.common.collect.testing.MapTestSuiteBuilder}.
39   *
40   * @author George van den Driessche
41   * @author Chris Povirk
42   */
43  @SuppressWarnings("unchecked") // too many "unchecked generic array creations"
44  @GwtCompatible
45  public class MapRemoveTester<K, V> extends AbstractMapTester<K, V> {
46    @MapFeature.Require(SUPPORTS_REMOVE)
47    @CollectionSize.Require(absent = ZERO)
48    public void testRemove_present() {
49      int initialSize = getMap().size();
50      assertEquals("remove(present) should return the associated value", v0(), getMap().remove(k0()));
51      assertEquals(
52          "remove(present) should decrease a map's size by one.", initialSize - 1, getMap().size());
53      expectMissing(e0());
54    }
55  
56    @MapFeature.Require({FAILS_FAST_ON_CONCURRENT_MODIFICATION, SUPPORTS_REMOVE})
57    @CollectionSize.Require(SEVERAL)
58    public void testRemovePresentConcurrentWithEntrySetIteration() {
59      try {
60        Iterator<Entry<K, V>> iterator = getMap().entrySet().iterator();
61        getMap().remove(k0());
62        iterator.next();
63        fail("Expected ConcurrentModificationException");
64      } catch (ConcurrentModificationException expected) {
65        // success
66      }
67    }
68  
69    @MapFeature.Require({FAILS_FAST_ON_CONCURRENT_MODIFICATION, SUPPORTS_REMOVE})
70    @CollectionSize.Require(SEVERAL)
71    public void testRemovePresentConcurrentWithKeySetIteration() {
72      try {
73        Iterator<K> iterator = getMap().keySet().iterator();
74        getMap().remove(k0());
75        iterator.next();
76        fail("Expected ConcurrentModificationException");
77      } catch (ConcurrentModificationException expected) {
78        // success
79      }
80    }
81  
82    @MapFeature.Require({FAILS_FAST_ON_CONCURRENT_MODIFICATION, SUPPORTS_REMOVE})
83    @CollectionSize.Require(SEVERAL)
84    public void testRemovePresentConcurrentWithValuesIteration() {
85      try {
86        Iterator<V> iterator = getMap().values().iterator();
87        getMap().remove(k0());
88        iterator.next();
89        fail("Expected ConcurrentModificationException");
90      } catch (ConcurrentModificationException expected) {
91        // success
92      }
93    }
94  
95    @MapFeature.Require(SUPPORTS_REMOVE)
96    public void testRemove_notPresent() {
97      assertNull("remove(notPresent) should return null", getMap().remove(k3()));
98      expectUnchanged();
99    }
100 
101   @MapFeature.Require({SUPPORTS_REMOVE, ALLOWS_NULL_KEYS})
102   @CollectionSize.Require(absent = ZERO)
103   public void testRemove_nullPresent() {
104     initMapWithNullKey();
105 
106     int initialSize = getMap().size();
107     assertEquals(
108         "remove(null) should return the associated value",
109         getValueForNullKey(),
110         getMap().remove(null));
111     assertEquals(
112         "remove(present) should decrease a map's size by one.", initialSize - 1, getMap().size());
113     expectMissing(entry(null, getValueForNullKey()));
114   }
115 
116   @MapFeature.Require(absent = SUPPORTS_REMOVE)
117   @CollectionSize.Require(absent = ZERO)
118   public void testRemove_unsupported() {
119     try {
120       getMap().remove(k0());
121       fail("remove(present) should throw UnsupportedOperationException");
122     } catch (UnsupportedOperationException expected) {
123     }
124     expectUnchanged();
125     assertEquals("remove(present) should not remove the element", v0(), get(k0()));
126   }
127 
128   @MapFeature.Require(absent = SUPPORTS_REMOVE)
129   public void testRemove_unsupportedNotPresent() {
130     try {
131       assertNull(
132           "remove(notPresent) should return null or throw UnsupportedOperationException",
133           getMap().remove(k3()));
134     } catch (UnsupportedOperationException tolerated) {
135     }
136     expectUnchanged();
137     expectMissing(e3());
138   }
139 
140   @MapFeature.Require(value = SUPPORTS_REMOVE, absent = ALLOWS_NULL_KEY_QUERIES)
141   public void testRemove_nullQueriesNotSupported() {
142     try {
143       assertNull(
144           "remove(null) should return null or throw NullPointerException", getMap().remove(null));
145     } catch (NullPointerException tolerated) {
146     }
147     expectUnchanged();
148   }
149 
150   @MapFeature.Require({SUPPORTS_REMOVE, ALLOWS_NULL_KEY_QUERIES})
151   public void testRemove_nullSupportedMissing() {
152     assertNull("remove(null) should return null", getMap().remove(null));
153     expectUnchanged();
154   }
155 
156   @MapFeature.Require(SUPPORTS_REMOVE)
157   public void testRemove_wrongType() {
158     try {
159       assertNull(getMap().remove(WrongType.VALUE));
160     } catch (ClassCastException tolerated) {
161     }
162     expectUnchanged();
163   }
164 }