001/*
002 * Copyright (C) 2008 The Guava Authors
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 * http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016
017package com.google.common.collect.testing.testers;
018
019import static com.google.common.collect.testing.features.CollectionSize.SEVERAL;
020import static com.google.common.collect.testing.features.CollectionSize.ZERO;
021import static com.google.common.collect.testing.features.MapFeature.FAILS_FAST_ON_CONCURRENT_MODIFICATION;
022import static com.google.common.collect.testing.features.MapFeature.SUPPORTS_REMOVE;
023import static org.junit.Assert.assertThrows;
024
025import com.google.common.annotations.GwtCompatible;
026import com.google.common.collect.testing.AbstractMapTester;
027import com.google.common.collect.testing.features.CollectionSize;
028import com.google.common.collect.testing.features.MapFeature;
029import java.util.ConcurrentModificationException;
030import java.util.Iterator;
031import java.util.Map.Entry;
032
033/**
034 * A generic JUnit test which tests {@code clear()} operations on a map. Can't be invoked directly;
035 * please see {@link com.google.common.collect.testing.MapTestSuiteBuilder}.
036 *
037 * @author George van den Driessche
038 * @author Chris Povirk
039 */
040@GwtCompatible
041public class MapClearTester<K, V> extends AbstractMapTester<K, V> {
042  @MapFeature.Require(SUPPORTS_REMOVE)
043  public void testClear() {
044    getMap().clear();
045    assertTrue("After clear(), a map should be empty.", getMap().isEmpty());
046    assertEquals(0, getMap().size());
047    assertFalse(getMap().entrySet().iterator().hasNext());
048  }
049
050  @MapFeature.Require({FAILS_FAST_ON_CONCURRENT_MODIFICATION, SUPPORTS_REMOVE})
051  @CollectionSize.Require(SEVERAL)
052  public void testClearConcurrentWithEntrySetIteration() {
053    Iterator<Entry<K, V>> iterator = getMap().entrySet().iterator();
054    getMap().clear();
055    assertThrows(ConcurrentModificationException.class, iterator::next);
056  }
057
058  @MapFeature.Require({FAILS_FAST_ON_CONCURRENT_MODIFICATION, SUPPORTS_REMOVE})
059  @CollectionSize.Require(SEVERAL)
060  public void testClearConcurrentWithKeySetIteration() {
061    Iterator<K> iterator = getMap().keySet().iterator();
062    getMap().clear();
063    assertThrows(ConcurrentModificationException.class, iterator::next);
064  }
065
066  @MapFeature.Require({FAILS_FAST_ON_CONCURRENT_MODIFICATION, SUPPORTS_REMOVE})
067  @CollectionSize.Require(SEVERAL)
068  public void testClearConcurrentWithValuesIteration() {
069    Iterator<V> iterator = getMap().values().iterator();
070    getMap().clear();
071    assertThrows(ConcurrentModificationException.class, iterator::next);
072  }
073
074  @MapFeature.Require(absent = SUPPORTS_REMOVE)
075  @CollectionSize.Require(absent = ZERO)
076  public void testClear_unsupported() {
077    assertThrows(UnsupportedOperationException.class, () -> getMap().clear());
078    expectUnchanged();
079  }
080
081  @MapFeature.Require(absent = SUPPORTS_REMOVE)
082  @CollectionSize.Require(ZERO)
083  public void testClear_unsupportedByEmptyCollection() {
084    try {
085      getMap().clear();
086    } catch (UnsupportedOperationException tolerated) {
087    }
088    expectUnchanged();
089  }
090}