1 /* 2 * Copyright (C) 2007 The Guava Authors 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except 5 * in compliance with the License. You may obtain a copy of the License at 6 * 7 * http://www.apache.org/licenses/LICENSE-2.0 8 * 9 * Unless required by applicable law or agreed to in writing, software distributed under the License 10 * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express 11 * or implied. See the License for the specific language governing permissions and limitations under 12 * the License. 13 */ 14 15 package com.google.common.collect; 16 17 import static com.google.common.base.Preconditions.checkArgument; 18 19 import com.google.common.annotations.GwtCompatible; 20 import com.google.common.collect.Multiset.Entry; 21 22 import java.io.Serializable; 23 import java.util.Iterator; 24 import java.util.Map; 25 import java.util.concurrent.atomic.AtomicInteger; 26 27 /** 28 * Unit test for {@link AbstractMultiset}. 29 * 30 * @author Kevin Bourrillion 31 * @author Louis Wasserman 32 */ 33 @SuppressWarnings("serial") // No serialization is used in this test 34 @GwtCompatible 35 public class SimpleAbstractMultisetTest extends AbstractMultisetTest { 36 37 @Override protected <E> Multiset<E> create() { 38 return new SimpleAbstractMultiset<E>(); 39 } 40 41 public void testFastAddAllMultiset() { 42 final AtomicInteger addCalls = new AtomicInteger(); 43 Multiset<String> multiset = new NoRemoveMultiset<String>() { 44 @Override 45 public int add(String element, int occurrences) { 46 addCalls.incrementAndGet(); 47 return super.add(element, occurrences); 48 } 49 }; 50 ImmutableMultiset<String> adds = 51 new ImmutableMultiset.Builder<String>().addCopies("x", 10).build(); 52 multiset.addAll(adds); 53 assertEquals(addCalls.get(), 1); 54 } 55 56 public void testRemoveUnsupported() { 57 Multiset<String> multiset = new NoRemoveMultiset<String>(); 58 multiset.add("a"); 59 try { 60 multiset.remove("a"); 61 fail(); 62 } catch (UnsupportedOperationException expected) {} 63 assertTrue(multiset.contains("a")); 64 } 65 66 private static class NoRemoveMultiset<E> extends AbstractMultiset<E> 67 implements Serializable { 68 final Map<E, Integer> backingMap = Maps.newHashMap(); 69 70 @Override public int add(E element, int occurrences) { 71 checkArgument(occurrences >= 0); 72 Integer frequency = backingMap.get(element); 73 if (frequency == null) { 74 frequency = 0; 75 } 76 if (occurrences == 0) { 77 return frequency; 78 } 79 checkArgument(occurrences <= Integer.MAX_VALUE - frequency); 80 backingMap.put(element, frequency + occurrences); 81 return frequency; 82 } 83 84 @Override 85 Iterator<Entry<E>> entryIterator() { 86 final Iterator<Map.Entry<E, Integer>> backingEntries = backingMap.entrySet().iterator(); 87 return new Iterator<Multiset.Entry<E>>() { 88 @Override 89 public boolean hasNext() { 90 return backingEntries.hasNext(); 91 } 92 93 @Override 94 public Multiset.Entry<E> next() { 95 final Map.Entry<E, Integer> mapEntry = backingEntries.next(); 96 return new Multisets.AbstractEntry<E>() { 97 @Override 98 public E getElement() { 99 return mapEntry.getKey(); 100 } 101 102 @Override 103 public int getCount() { 104 Integer frequency = backingMap.get(getElement()); 105 return (frequency == null) ? 0 : frequency; 106 } 107 }; 108 } 109 110 @Override 111 public void remove() { 112 backingEntries.remove(); 113 } 114 }; 115 } 116 117 @Override 118 int distinctElements() { 119 return backingMap.size(); 120 } 121 } 122 123 private static class SimpleAbstractMultiset<E> extends NoRemoveMultiset<E> { 124 @SuppressWarnings("unchecked") 125 @Override public int remove(Object element, int occurrences) { 126 checkArgument(occurrences >= 0); 127 Integer count = backingMap.get(element); 128 if (count == null) { 129 return 0; 130 } else if (count > occurrences) { 131 backingMap.put((E) element, count - occurrences); 132 return count; 133 } else { 134 return backingMap.remove(element); 135 } 136 } 137 } 138 } 139
