ConcurrentSkipListIntObjMultimap.java — netty Source File

Source Code

/*
 * Copyright 2026 The Netty Project
 *
 * The Netty Project licenses this file to you 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:
 *
 *   https://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.
 */
/*
 * Written by Doug Lea with assistance from members of JCP JSR-166
 * Expert Group and released to the public domain, as explained at
 * https://creativecommons.org/publicdomain/zero/1.0/
 *
 * With substantial modifications by The Netty Project team.
 */
package io.netty.util.concurrent;

import io.netty.util.internal.PlatformDependent;

import java.lang.invoke.MethodHandle;
import java.lang.invoke.MethodHandles;
import java.lang.invoke.MethodType;
import java.lang.invoke.VarHandle;
import java.util.Iterator;
import java.util.NoSuchElementException;
import java.util.Objects;
import java.util.concurrent.ThreadLocalRandom;
import java.util.concurrent.atomic.AtomicReferenceFieldUpdater;
import java.util.function.BiConsumer;
import java.util.function.BiFunction;
import java.util.concurrent.atomic.LongAdder;

import static java.util.Objects.requireNonNull;

/**
 * A scalable concurrent multimap implementation.
 * The map is sorted according to the natural ordering of its {@code int} keys.
 *
 * <p>This class implements a concurrent variant of <a
 * href="https://en.wikipedia.org/wiki/Skip_list" target="_top">SkipLists</a>
 * providing expected average <i>log(n)</i> time cost for the
 * {@code containsKey}, {@code get}, {@code put} and
 * {@code remove} operations and their variants.  Insertion, removal,
 * update, and access operations safely execute concurrently by
 * multiple threads.
 *
 * <p>This class is a multimap, which means the same key can be associated with
 * multiple values. Each such instance will be represented by a separate
 * {@code IntEntry}. There is no defined ordering for the values mapped to
 * the same key.
 *
 * <p>As a multimap, certain atomic operations like {@code putIfPresent},
 * {@code compute}, or {@code computeIfPresent}, cannot be supported.
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