73 lines
2.8 KiB
Java
73 lines
2.8 KiB
Java
/*
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* Copyright 2016 The Netty Project
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*
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* The Netty Project licenses this file to you under the Apache License,
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* version 2.0 (the "License"); you may not use this file except in compliance
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* with the License. You may obtain a copy of the License at:
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*/
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package io.netty.util.concurrent;
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import io.netty.util.internal.ObjectUtil;
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import java.util.concurrent.RejectedExecutionException;
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import java.util.concurrent.TimeUnit;
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import java.util.concurrent.locks.LockSupport;
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/**
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* Expose helper methods which create different {@link RejectedExecutionHandler}s.
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*/
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public final class RejectedExecutionHandlers {
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private static final RejectedExecutionHandler REJECT = new RejectedExecutionHandler() {
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@Override
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public void rejected(Runnable task, SingleThreadEventExecutor executor) {
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throw new RejectedExecutionException();
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}
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};
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private RejectedExecutionHandlers() { }
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/**
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* Returns a {@link RejectedExecutionHandler} that will always just throw a {@link RejectedExecutionException}.
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*/
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public static RejectedExecutionHandler reject() {
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return REJECT;
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}
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/**
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* Tries to backoff when the task can not be added due restrictions for an configured amount of time. This
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* is only done if the task was added from outside of the event loop which means
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* {@link EventExecutor#inEventLoop()} returns {@code false}.
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*/
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public static RejectedExecutionHandler backoff(final int retries, long backoffAmount, TimeUnit unit) {
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ObjectUtil.checkPositive(retries, "retries");
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final long backOffNanos = unit.toNanos(backoffAmount);
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return new RejectedExecutionHandler() {
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@Override
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public void rejected(Runnable task, SingleThreadEventExecutor executor) {
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if (!executor.inEventLoop()) {
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for (int i = 0; i < retries; i++) {
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// Try to wake up the executor so it will empty its task queue.
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executor.wakeup(false);
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LockSupport.parkNanos(backOffNanos);
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if (executor.offerTask(task)) {
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return;
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}
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}
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}
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// Either we tried to add the task from within the EventLoop or we was not able to add it even with
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// backoff.
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throw new RejectedExecutionException();
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}
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};
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}
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}
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