239 lines
9.2 KiB
Java
239 lines
9.2 KiB
Java
/*
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* Copyright 2012 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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* https://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.channel;
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import static io.netty.util.internal.ObjectUtil.checkPositive;
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import static java.util.Objects.requireNonNull;
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import io.netty.util.concurrent.RejectedExecutionHandler;
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import io.netty.util.concurrent.RejectedExecutionHandlers;
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import io.netty.util.concurrent.SingleThreadEventExecutor;
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import io.netty.util.internal.PlatformDependent;
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import io.netty.util.internal.SystemPropertyUtil;
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import java.util.Queue;
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import java.util.concurrent.Executor;
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import java.util.concurrent.ThreadFactory;
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/**
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* {@link EventLoop} that execute all its submitted tasks in a single thread and uses an {@link IoHandler} for
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* IO processing.
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*/
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public class SingleThreadEventLoop extends SingleThreadEventExecutor implements EventLoop {
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protected static final int DEFAULT_MAX_PENDING_TASKS = Math.max(16,
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SystemPropertyUtil.getInt("io.netty.eventLoop.maxPendingTasks", Integer.MAX_VALUE));
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// TODO: Is this a sensible default ?
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protected static final int DEFAULT_MAX_TASKS_PER_RUN = Math.max(1,
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SystemPropertyUtil.getInt("io.netty.eventLoop.maxTaskPerRun", 1024 * 4));
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private final IoExecutionContext context = new IoExecutionContext() {
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@Override
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public boolean canBlock() {
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assert inEventLoop();
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return !SingleThreadEventLoop.this.hasTasks() && !SingleThreadEventLoop.this.hasScheduledTasks();
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}
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@Override
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public long delayNanos(long currentTimeNanos) {
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assert inEventLoop();
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return SingleThreadEventLoop.this.delayNanos(currentTimeNanos);
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}
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@Override
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public long deadlineNanos() {
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assert inEventLoop();
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return SingleThreadEventLoop.this.deadlineNanos();
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}
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};
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private final Unsafe unsafe = new Unsafe() {
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@Override
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public void register(Channel channel) throws Exception {
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SingleThreadEventLoop.this.register(channel);
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}
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@Override
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public void deregister(Channel channel) throws Exception {
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SingleThreadEventLoop.this.deregister(channel);
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}
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};
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private final IoHandler ioHandler;
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private final int maxTasksPerRun;
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/**
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* Create a new instance
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*
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* @param threadFactory the {@link ThreadFactory} which will be used for the used {@link Thread}
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* @param ioHandler the {@link IoHandler} to use.
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*/
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public SingleThreadEventLoop(ThreadFactory threadFactory, IoHandler ioHandler) {
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this(threadFactory, ioHandler, DEFAULT_MAX_PENDING_TASKS, RejectedExecutionHandlers.reject());
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}
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/**
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* Create a new instance
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*
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* @param executor the {@link Executor} which will be used to run this {@link EventLoop}.
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* @param ioHandler the {@link IoHandler} to use.
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*/
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public SingleThreadEventLoop(Executor executor, IoHandler ioHandler) {
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this(executor, ioHandler, DEFAULT_MAX_PENDING_TASKS, RejectedExecutionHandlers.reject());
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}
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/**
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* Create a new instance
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*
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* @param threadFactory the {@link ThreadFactory} which will be used for the used {@link Thread}
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* @param ioHandler the {@link IoHandler} to use.
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* @param maxPendingTasks the maximum number of pending tasks before new tasks will be rejected.
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* @param rejectedHandler the {@link RejectedExecutionHandler} to use.
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*/
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public SingleThreadEventLoop(ThreadFactory threadFactory,
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IoHandler ioHandler, int maxPendingTasks,
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RejectedExecutionHandler rejectedHandler) {
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this(threadFactory, ioHandler, maxPendingTasks, rejectedHandler, DEFAULT_MAX_TASKS_PER_RUN);
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}
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/**
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* Create a new instance
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*
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* @param executor the {@link Executor} which will be used to run this {@link EventLoop}.
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* @param ioHandler the {@link IoHandler} to use.
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* @param maxPendingTasks the maximum number of pending tasks before new tasks will be rejected.
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* @param rejectedHandler the {@link RejectedExecutionHandler} to use.
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*/
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public SingleThreadEventLoop(Executor executor,
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IoHandler ioHandler, int maxPendingTasks,
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RejectedExecutionHandler rejectedHandler) {
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this(executor, ioHandler, maxPendingTasks, rejectedHandler, DEFAULT_MAX_TASKS_PER_RUN);
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}
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/**
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* Create a new instance
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*
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* @param threadFactory the {@link ThreadFactory} which will be used for the used {@link Thread}
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* @param ioHandler the {@link IoHandler} to use.
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* @param maxPendingTasks the maximum number of pending tasks before new tasks will be rejected.
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* @param rejectedHandler the {@link RejectedExecutionHandler} to use.
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* @param maxTasksPerRun the maximum number of tasks per {@link EventLoop} run that will be processed
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* before trying to handle IO again.
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*/
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public SingleThreadEventLoop(ThreadFactory threadFactory,
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IoHandler ioHandler, int maxPendingTasks,
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RejectedExecutionHandler rejectedHandler, int maxTasksPerRun) {
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super(threadFactory, maxPendingTasks, rejectedHandler);
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this.ioHandler = requireNonNull(ioHandler, "ioHandler");
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this.maxTasksPerRun = checkPositive(maxTasksPerRun, "maxTasksPerRun");
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}
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/**
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* Create a new instance
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*
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* @param executor the {@link Executor} which will be used to run this {@link EventLoop}.
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* @param ioHandler the {@link IoHandler} to use.
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* @param maxPendingTasks the maximum number of pending tasks before new tasks will be rejected.
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* @param rejectedHandler the {@link RejectedExecutionHandler} to use.
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* @param maxTasksPerRun the maximum number of tasks per {@link EventLoop} run that will be processed
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* before trying to handle IO again.
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*/
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public SingleThreadEventLoop(Executor executor,
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IoHandler ioHandler, int maxPendingTasks,
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RejectedExecutionHandler rejectedHandler, int maxTasksPerRun) {
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super(executor, maxPendingTasks, rejectedHandler);
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this.ioHandler = requireNonNull(ioHandler, "ioHandler");
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this.maxTasksPerRun = checkPositive(maxTasksPerRun, "maxTasksPerRun");
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}
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@Override
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protected Queue<Runnable> newTaskQueue(int maxPendingTasks) {
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// This event loop never calls takeTask()
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return maxPendingTasks == Integer.MAX_VALUE ? PlatformDependent.newMpscQueue()
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: PlatformDependent.newMpscQueue(maxPendingTasks);
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}
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@Override
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protected final boolean wakesUpForTask(Runnable task) {
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return !(task instanceof NonWakeupRunnable);
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}
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/**
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* Marker interface for {@link Runnable} that will not trigger an {@link #wakeup(boolean)} in all cases.
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*/
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interface NonWakeupRunnable extends Runnable { }
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@Override
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public final Unsafe unsafe() {
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return unsafe;
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}
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// Methods that a user can override to easily add instrumentation and other things.
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@Override
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protected void run() {
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assert inEventLoop();
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do {
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runIo();
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if (isShuttingDown()) {
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ioHandler.prepareToDestroy();
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}
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runAllTasks(maxTasksPerRun);
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} while (!confirmShutdown());
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}
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/**
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* Called when IO will be processed for all the {@link Channel}s on this {@link SingleThreadEventLoop}.
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* This method returns the number of {@link Channel}s for which IO was processed.
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*
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* This method must be called from the {@link EventLoop} thread.
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*/
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protected int runIo() {
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assert inEventLoop();
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return ioHandler.run(context);
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}
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/**
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* Called once a {@link Channel} should be registered on this {@link SingleThreadEventLoop}.
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*
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* This method must be called from the {@link EventLoop} thread.
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*/
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protected void register(Channel channel) throws Exception {
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assert inEventLoop();
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ioHandler.register(channel);
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}
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/**
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* Called once a {@link Channel} should be deregistered from this {@link SingleThreadEventLoop}.
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*/
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protected void deregister(Channel channel) throws Exception {
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assert inEventLoop();
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ioHandler.deregister(channel);
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}
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@Override
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protected final void wakeup(boolean inEventLoop) {
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ioHandler.wakeup(inEventLoop);
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}
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@Override
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protected final void cleanup() {
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assert inEventLoop();
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ioHandler.destroy();
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}
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}
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