org.apache.hudi.org.apache.hadoop.hbase.regionserver.wal.RingBufferTruck Maven / Gradle / Ivy
/**
*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF 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 org.apache.hadoop.hbase.regionserver.wal;
import org.apache.yetus.audience.InterfaceAudience;
/**
* A 'truck' to carry a payload across the ring buffer from Handler to WAL. Has EITHER a
* {@link FSWALEntry} for making an append OR it has a {@link SyncFuture} to represent a 'sync'
* invocation. Truck instances are reused by the disruptor when it gets around to it so their
* payload references must be discarded on consumption to release them to GC.
*/
@InterfaceAudience.Private
final class RingBufferTruck {
public enum Type {
APPEND, SYNC, EMPTY
}
private Type type = Type.EMPTY;
/**
* Either this syncFuture is set or entry is set, but not both.
*/
private SyncFuture sync;
private FSWALEntry entry;
/**
* Load the truck with a {@link FSWALEntry}.
*/
void load(FSWALEntry entry) {
this.entry = entry;
this.type = Type.APPEND;
}
/**
* Load the truck with a {@link SyncFuture}.
*/
void load(final SyncFuture syncFuture) {
this.sync = syncFuture;
this.type = Type.SYNC;
}
/**
* @return the type of this truck's payload.
*/
Type type() {
return type;
}
/**
* Unload the truck of its {@link FSWALEntry} payload. The internal reference is released.
*/
FSWALEntry unloadAppend() {
FSWALEntry entry = this.entry;
this.entry = null;
this.type = Type.EMPTY;
return entry;
}
/**
* Unload the truck of its {@link SyncFuture} payload. The internal reference is released.
*/
SyncFuture unloadSync() {
SyncFuture sync = this.sync;
this.sync = null;
this.type = Type.EMPTY;
return sync;
}
}