shz.core.node.ConcurrentIDNode 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.AtomicIntegerFieldUpdater;
import java.util.concurrent.atomic.AtomicReferenceFieldUpdater;

/**
 * 元素类型为int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 ConcurrentIDNode implements DNode {
    private static final long serialVersionUID = -7774549081458197249L;
    public volatile int val;
    protected volatile ConcurrentIDNode next;
    protected volatile ConcurrentIDNode prev;

    protected ConcurrentIDNode(int val) {
        this.val = val;
    }

    public static ConcurrentIDNode of(int e) {
        return new ConcurrentIDNode(e);
    }

    public static ConcurrentIDNode of() {
        return of(0);
    }

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

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

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

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

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

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

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

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

    @Override
    public final ConcurrentIDNode addNext(ConcurrentIDNode node) {
        while (true) {
            ConcurrentIDNode 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 ConcurrentIDNode addPrev(ConcurrentIDNode node) {
        while (true) {
            ConcurrentIDNode 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() {
        ConcurrentIDNode prev = this.prev;
        ConcurrentIDNode 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 ConcurrentIDNode addNext(int e) {
        return addNext(of(e));
    }

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

    public final ConcurrentIDNode addPrev(int e) {
        return addPrev(of(e));
    }

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