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Standard library for the Scala Programming Language

There is a newer version: 2.13.13

/*
 * Scala (https://www.scala-lang.org)
 *
 * Copyright EPFL and Lightbend, Inc.
 *
 * Licensed under Apache License 2.0
 * (http://www.apache.org/licenses/LICENSE-2.0).
 *
 * See the NOTICE file distributed with this work for
 * additional information regarding copyright ownership.
 */

package scala.collection.concurrent;

import java.util.concurrent.atomic.AtomicReferenceFieldUpdater;

abstract class MainNode extends BasicNode {

    @SuppressWarnings("unchecked")
    public static final AtomicReferenceFieldUpdater, MainNode> updater =
            AtomicReferenceFieldUpdater.newUpdater((Class>) (Class) MainNode.class, (Class>) (Class) MainNode.class, "prev");

    public volatile MainNode prev = null;

    public abstract int cachedSize(Object ct);

    public boolean CAS_PREV(MainNode oldval, MainNode nval) {
        return updater.compareAndSet(this, oldval, nval);
    }

    public void WRITE_PREV(MainNode nval) {
        updater.set(this, nval);
    }

    // do we need this? unclear in the javadocs...
    // apparently not - volatile reads are supposed to be safe
    // regardless of whether there are concurrent ARFU updates
    @Deprecated @SuppressWarnings("unchecked")
    public MainNode READ_PREV() {
        return (MainNode) updater.get(this);
    }

}