/*                     __                                               *\
 **     ________ ___   / /  ___     Scala API                            **
 **    / __/ __// _ | / /  / _ |    (c) 2003-2012, LAMP/EPFL             **
 **  __\ \/ /__/ __ |/ /__/ __ |    http://scala-lang.org/               **
 ** /____/\___/_/ |_/____/_/ | |                                         **
 **                          |/                                          **
\*                                                                      */

package org.opendaylight.yangtools.triemap;

import java.util.concurrent.atomic.AtomicReferenceFieldUpdater;

abstract class MainNode<K, V> extends BasicNode {

    public static final AtomicReferenceFieldUpdater<MainNode, MainNode> updater = AtomicReferenceFieldUpdater.newUpdater (MainNode.class, MainNode.class, "prev");

    public volatile MainNode<K, V> prev = null;

    public abstract int cachedSize (Object ct);

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

    public void WRITE_PREV (MainNode<K, V> 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
    public MainNode<K, V> READ_PREV () {
        return updater.get (this);
    }

}