com.hazelcast.internal.networking.nio.NioPipelineTask Maven / Gradle / Ivy
/*
* Copyright (c) 2008-2021, Hazelcast, Inc. All Rights Reserved.
*
* Licensed 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 com.hazelcast.internal.networking.nio;
import static java.lang.Thread.currentThread;
/**
* A {@link Runnable} that gets executed on the {@link NioThread} owning the pipeline.
*
* Normally this is a pretty simple task, just schedule the runnable on the owner
* using {@link NioThread#addTaskAndWakeup(Runnable)}.
*
* The problem however is that pipeline migration can cause a task to end up at a
* NioThread that doesn't own the pipeline any longer. Therefore, this task does a
* check when it is executed if the owner of the pipeline is the same as the
* current thread. If it is, then the {@link #run0()} is called. If it isn't, the
* task is sent to the {@link NioPipeline#ownerAddTaskAndWakeup(Runnable)} which will
* make sure the task is sent to the right NioThread.
*/
abstract class NioPipelineTask implements Runnable {
private final NioPipeline pipeline;
NioPipelineTask(NioPipeline pipeline) {
this.pipeline = pipeline;
}
@Override
public final void run() {
if (pipeline.owner() == currentThread()) {
// the task is executed by the proper thread
try {
run0();
} catch (Exception e) {
pipeline.onError(e);
}
} else {
// the pipeline is migrating or already has migrated.
// let's reschedule this task on the pipeline, so it will
// be picked up by the new owner.
pipeline.ownerAddTaskAndWakeup(this);
}
}
protected abstract void run0() throws Exception;
}