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/*
* Copyright (C) 2007 The Guava Authors
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
* in compliance with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software distributed under the License
* is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
* or implied. See the License for the specific language governing permissions and limitations under
* the License.
*/
package com.google.common.collect;
import static com.google.common.base.Preconditions.checkArgument;
import com.google.common.annotations.GwtCompatible;
import java.io.Serializable;
import java.util.Iterator;
import java.util.Map;
import java.util.concurrent.atomic.AtomicInteger;
import javax.annotation.Nullable;
/**
* Unit test for {@link AbstractMultiset}.
*
* @author Kevin Bourrillion
* @author Louis Wasserman
*/
@SuppressWarnings("serial") // No serialization is used in this test
@GwtCompatible
public class SimpleAbstractMultisetTest extends AbstractMultisetTest {
@Override protected <E> Multiset<E> create() {
return new SimpleAbstractMultiset<E>();
}
public void testFastAddAllMultiset() {
final AtomicInteger addCalls = new AtomicInteger();
Multiset<String> multiset = new NoRemoveMultiset<String>() {
@Override
public int add(String element, int occurrences) {
addCalls.incrementAndGet();
return super.add(element, occurrences);
}
};
ImmutableMultiset<String> adds =
new ImmutableMultiset.Builder<String>().addCopies("x", 10).build();
multiset.addAll(adds);
assertEquals(addCalls.get(), 1);
}
public void testRemoveUnsupported() {
Multiset<String> multiset = new NoRemoveMultiset<String>();
multiset.add("a");
try {
multiset.remove("a");
fail();
} catch (UnsupportedOperationException expected) {}
assertTrue(multiset.contains("a"));
}
private static class NoRemoveMultiset<E> extends AbstractMultiset<E>
implements Serializable {
final Map<E, Integer> backingMap = Maps.newHashMap();
@Override public int add(@Nullable E element, int occurrences) {
checkArgument(occurrences >= 0);
Integer frequency = backingMap.get(element);
if (frequency == null) {
frequency = 0;
}
if (occurrences == 0) {
return frequency;
}
checkArgument(occurrences <= Integer.MAX_VALUE - frequency);
backingMap.put(element, frequency + occurrences);
return frequency;
}
@Override
Iterator<Entry<E>> entryIterator() {
final Iterator<Map.Entry<E, Integer>> backingEntries = backingMap.entrySet().iterator();
return new Iterator<Multiset.Entry<E>>() {
@Override
public boolean hasNext() {
return backingEntries.hasNext();
}
@Override
public Multiset.Entry<E> next() {
final Map.Entry<E, Integer> mapEntry = backingEntries.next();
return new Multisets.AbstractEntry<E>() {
@Override
public E getElement() {
return mapEntry.getKey();
}
@Override
public int getCount() {
Integer frequency = backingMap.get(getElement());
return (frequency == null) ? 0 : frequency;
}
};
}
@Override
public void remove() {
backingEntries.remove();
}
};
}
@Override
int distinctElements() {
return backingMap.size();
}
}
private static class SimpleAbstractMultiset<E> extends NoRemoveMultiset<E> {
@SuppressWarnings("unchecked")
@Override public int remove(@Nullable Object element, int occurrences) {
checkArgument(occurrences >= 0);
Integer count = backingMap.get(element);
if (count == null) {
return 0;
} else if (count > occurrences) {
backingMap.put((E) element, count - occurrences);
return count;
} else {
return backingMap.remove(element);
}
}
}
}
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