com.google.common.collect.JdkBackedImmutableMultiset Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of guava Show documentation
Show all versions of guava Show documentation
Guava is a suite of core and expanded libraries that include
utility classes, google's collections, io classes, and much
much more.
/*
* Copyright (C) 2018 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.checkNotNull;
import com.google.common.annotations.GwtCompatible;
import com.google.common.primitives.Ints;
import com.google.errorprone.annotations.concurrent.LazyInit;
import java.util.Collection;
import java.util.Map;
import javax.annotation.CheckForNull;
/**
* An implementation of ImmutableMultiset backed by a JDK Map and a list of entries. Used to protect
* against hash flooding attacks.
*
* @author Louis Wasserman
*/
@GwtCompatible
@ElementTypesAreNonnullByDefault
final class JdkBackedImmutableMultiset extends ImmutableMultiset {
private final Map delegateMap;
private final ImmutableList> entries;
private final long size;
static ImmutableMultiset create(Collection extends Entry extends E>> entries) {
@SuppressWarnings("unchecked")
Entry[] entriesArray = entries.toArray(new Entry[0]);
Map delegateMap = Maps.newHashMapWithExpectedSize(entriesArray.length);
long size = 0;
for (int i = 0; i < entriesArray.length; i++) {
Entry entry = entriesArray[i];
int count = entry.getCount();
size += count;
E element = checkNotNull(entry.getElement());
delegateMap.put(element, count);
if (!(entry instanceof Multisets.ImmutableEntry)) {
entriesArray[i] = Multisets.immutableEntry(element, count);
}
}
return new JdkBackedImmutableMultiset<>(
delegateMap, ImmutableList.asImmutableList(entriesArray), size);
}
private JdkBackedImmutableMultiset(
Map delegateMap, ImmutableList> entries, long size) {
this.delegateMap = delegateMap;
this.entries = entries;
this.size = size;
}
@Override
public int count(@CheckForNull Object element) {
return delegateMap.getOrDefault(element, 0);
}
@LazyInit @CheckForNull private transient ImmutableSet elementSet;
@Override
public ImmutableSet elementSet() {
ImmutableSet result = elementSet;
return (result == null) ? elementSet = new ElementSet<>(entries, this) : result;
}
@Override
Entry getEntry(int index) {
return entries.get(index);
}
@Override
boolean isPartialView() {
return false;
}
@Override
public int size() {
return Ints.saturatedCast(size);
}
}
© 2015 - 2024 Weber Informatics LLC | Privacy Policy