shz.core.node.ConcurrentJDNode Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of core
${project.artifactId}
There is a newer version: 2024.0.2
package shz.core.node;

import java.util.concurrent.atomic.AtomicLongFieldUpdater;
import java.util.concurrent.atomic.AtomicReferenceFieldUpdater;

/**
 * 元素类型为long支持并发的双向链表节点
 * 
 * 24*n(n为元素个数)
 * 
 * B=16+24*n
 */
@SuppressWarnings("restriction")
public class ConcurrentJDNode implements DNode {
    private static final long serialVersionUID = 6121417618430692988L;
    public volatile long val;
    protected volatile ConcurrentJDNode next;
    protected volatile ConcurrentJDNode prev;

    protected ConcurrentJDNode(long val) {
        this.val = val;
    }

    public static ConcurrentJDNode of(long e) {
        return new ConcurrentJDNode(e);
    }

    public static ConcurrentJDNode of() {
        return of(0L);
    }

    private static final AtomicLongFieldUpdater valUpdater = AtomicLongFieldUpdater.newUpdater(ConcurrentJDNode.class, "val");
    private static final AtomicReferenceFieldUpdater nextUpdater = AtomicReferenceFieldUpdater.newUpdater(ConcurrentJDNode.class, ConcurrentJDNode.class, "next");
    private static final AtomicReferenceFieldUpdater prevUpdater = AtomicReferenceFieldUpdater.newUpdater(ConcurrentJDNode.class, ConcurrentJDNode.class, "prev");

    public boolean casVal(long expect, long update) {
        return valUpdater.compareAndSet(this, expect, update);
    }

    public boolean casNext(ConcurrentJDNode expect, ConcurrentJDNode update) {
        return nextUpdater.compareAndSet(this, expect, update);
    }

    public boolean casPrev(ConcurrentJDNode expect, ConcurrentJDNode update) {
        return prevUpdater.compareAndSet(this, expect, update);
    }

    @Override
    public final ConcurrentJDNode next() {
        return next;
    }

    @Override
    public final void next(ConcurrentJDNode node) {
        next = node;
    }

    @Override
    public final ConcurrentJDNode prev() {
        return prev;
    }

    @Override
    public final void prev(ConcurrentJDNode node) {
        prev = node;
    }

    @Override
    public final ConcurrentJDNode addNext(ConcurrentJDNode node) {
        while (true) {
            ConcurrentJDNode next = this.next;
            node.prev = this;
            node.next = next;
            if (!casNext(next, node)) continue;
            if (next != null) next.prev = node;
            break;
        }
        return node;
    }

    @Override
    public final ConcurrentJDNode addPrev(ConcurrentJDNode node) {
        while (true) {
            ConcurrentJDNode prev = this.prev;
            node.prev = prev;
            node.next = this;
            if (!casPrev(prev, node)) continue;
            if (prev != null) prev.next = node;
            break;
        }
        return node;
    }

    @Override
    public final void poll() {
        ConcurrentJDNode prev = this.prev;
        ConcurrentJDNode next = this.next;
        if (prev != null) {
            if (prev.casNext(this, next)) if (next != null) next.prev = prev;
        } else if (next != null) next.casPrev(this, null);
    }

    public final ConcurrentJDNode addNext(long e) {
        return addNext(of(e));
    }

    public final ConcurrentJDNode addNext(long... es) {
        ConcurrentJDNode next = this;
        for (long e : es) next = next.addNext(e);
        return next;
    }

    public final ConcurrentJDNode addPrev(long e) {
        return addPrev(of(e));
    }

    public final ConcurrentJDNode addPrev(long... es) {
        ConcurrentJDNode prev = this;
        for (long e : es) prev = prev.addPrev(e);
        return prev;
    }
}