com.alibaba.rocketmq.shade.io.netty.util.internal.MpscLinkedQueueTailRef Maven / Gradle / Ivy
/*
* Copyright 2014 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:
*
* http://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.
*/
package io.netty.util.internal;
import java.util.concurrent.atomic.AtomicReferenceFieldUpdater;
abstract class MpscLinkedQueueTailRef extends MpscLinkedQueuePad1 {
private static final long serialVersionUID = 8717072462993327429L;
@SuppressWarnings("rawtypes")
private static final AtomicReferenceFieldUpdater UPDATER;
static {
@SuppressWarnings("rawtypes")
AtomicReferenceFieldUpdater updater;
updater = PlatformDependent.newAtomicReferenceFieldUpdater(MpscLinkedQueueTailRef.class, "tailRef");
if (updater == null) {
updater = AtomicReferenceFieldUpdater.newUpdater(
MpscLinkedQueueTailRef.class, MpscLinkedQueueNode.class, "tailRef");
}
UPDATER = updater;
}
private transient volatile MpscLinkedQueueNode tailRef;
protected final MpscLinkedQueueNode tailRef() {
return tailRef;
}
protected final void setTailRef(MpscLinkedQueueNode tailRef) {
this.tailRef = tailRef;
}
@SuppressWarnings("unchecked")
protected final MpscLinkedQueueNode getAndSetTailRef(MpscLinkedQueueNode tailRef) {
// LOCK XCHG in JDK8, a CAS loop in JDK 7/6
return (MpscLinkedQueueNode) UPDATER.getAndSet(this, tailRef);
}
}