Package io.netty.channel.nio

Class NioEventLoop

java.lang.Object

java.util.concurrent.AbstractExecutorService

io.netty.util.concurrent.AbstractEventExecutor

io.netty.util.concurrent.AbstractScheduledEventExecutor

io.netty.util.concurrent.SingleThreadEventExecutor

io.netty.channel.SingleThreadEventLoop

io.netty.channel.nio.NioEventLoop

All Implemented Interfaces:

EventLoop, EventLoopGroup, EventExecutor, EventExecutorGroup, OrderedEventExecutor, AutoCloseable, Iterable<EventExecutor>, Executor, ExecutorService, ScheduledExecutorService

public final class NioEventLoop
extends SingleThreadEventLoop

SingleThreadEventLoop implementation which register the Channel's to a Selector and so does the multi-plexing of these in the event loop.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
private static final class	NioEventLoop.SelectorTuple

Nested classes/interfaces inherited from class io.netty.channel.SingleThreadEventLoop

SingleThreadEventLoop.ChannelsReadOnlyIterator<T extends Channel>

Nested classes/interfaces inherited from class io.netty.util.concurrent.SingleThreadEventExecutor

SingleThreadEventExecutor.NonWakeupRunnable

Nested classes/interfaces inherited from class io.netty.util.concurrent.AbstractEventExecutor

AbstractEventExecutor.LazyRunnable

Field Summary

Fields

Modifier and Type	Field	Description
private static final long	AWAKE
private int	cancelledKeys
private static final int	CLEANUP_INTERVAL
private static final boolean	DISABLE_KEY_SET_OPTIMIZATION
private int	ioRatio
private static final InternalLogger	logger
private static final int	MIN_PREMATURE_SELECTOR_RETURNS
private boolean	needsToSelectAgain
private final AtomicLong	nextWakeupNanos
private static final long	NONE
private final SelectorProvider	provider
private SelectedSelectionKeySet	selectedKeys
private final IntSupplier	selectNowSupplier
private Selector	selector	The NIO Selector.
private static final int	SELECTOR_AUTO_REBUILD_THRESHOLD
private final SelectStrategy	selectStrategy
private Selector	unwrappedSelector

Fields inherited from class io.netty.channel.SingleThreadEventLoop

DEFAULT_MAX_PENDING_TASKS

Constructor Summary

Constructors

Constructor	Description
NioEventLoop(NioEventLoopGroup parent, Executor executor, SelectorProvider selectorProvider, SelectStrategy strategy, RejectedExecutionHandler rejectedExecutionHandler, EventLoopTaskQueueFactory taskQueueFactory, EventLoopTaskQueueFactory tailTaskQueueFactory)

Method Summary

Modifier and Type	Method	Description
protected boolean	afterScheduledTaskSubmitted(long deadlineNanos)	See AbstractScheduledEventExecutor.beforeScheduledTaskSubmitted(long).
protected boolean	beforeScheduledTaskSubmitted(long deadlineNanos)	Called from arbitrary non-EventExecutor threads prior to scheduled task submission.
(package private) void	cancel(SelectionKey key)
protected void	cleanup()	Do nothing, sub-classes may override
private void	closeAll()
int	getIoRatio()	Returns the percentage of the desired amount of time spent for I/O in the event loop.
private static void	handleLoopException(Throwable t)
private static void	invokeChannelUnregistered(NioTask<SelectableChannel> task, SelectionKey k, Throwable cause)
protected Queue<Runnable>	newTaskQueue(int maxPendingTasks)	Create a new Queue which will holds the tasks to execute.
private static Queue<Runnable>	newTaskQueue(EventLoopTaskQueueFactory queueFactory)
private static Queue<Runnable>	newTaskQueue0(int maxPendingTasks)
private NioEventLoop.SelectorTuple	openSelector()
private void	processSelectedKey(SelectionKey k, AbstractNioChannel ch)
private static void	processSelectedKey(SelectionKey k, NioTask<SelectableChannel> task)
private void	processSelectedKeys()
private void	processSelectedKeysOptimized()
private void	processSelectedKeysPlain(Set<SelectionKey> selectedKeys)
void	rebuildSelector()	Replaces the current Selector of this event loop with newly created Selectors to work around the infamous epoll 100% CPU bug.
private void	rebuildSelector0()
void	register(SelectableChannel ch, int interestOps, NioTask<?> task)	Registers an arbitrary SelectableChannel, not necessarily created by Netty, to the Selector of this event loop.
private void	register0(SelectableChannel ch, int interestOps, NioTask<?> task)
int	registeredChannels()	Returns the number of Channels registered with this EventLoop or -1 if operation is not supported.
Iterator<Channel>	registeredChannelsIterator()
protected void	run()	Run the tasks in the SingleThreadEventExecutor.taskQueue
private int	select(long deadlineNanos)
private void	selectAgain()
(package private) int	selectNow()
SelectorProvider	selectorProvider()	Returns the SelectorProvider used by this NioEventLoop to obtain the Selector.
private boolean	selectReturnPrematurely(int selectCnt, boolean ranTasks, int strategy)
void	setIoRatio(int ioRatio)	Sets the percentage of the desired amount of time spent for I/O in the event loop.
private boolean	unexpectedSelectorWakeup(int selectCnt)
(package private) Selector	unwrappedSelector()
protected void	wakeup(boolean inEventLoop)

Methods inherited from class io.netty.channel.SingleThreadEventLoop

afterRunningAllTasks, executeAfterEventLoopIteration, hasTasks, next, parent, pendingTasks, register, register, register

Methods inherited from class io.netty.util.concurrent.SingleThreadEventExecutor

addShutdownHook, addTask, awaitTermination, confirmShutdown, deadlineNanos, delayNanos, execute, inEventLoop, interruptThread, invokeAll, invokeAll, invokeAny, invokeAny, isShutdown, isShuttingDown, isTerminated, lazyExecute, newTaskQueue, peekTask, pollTask, pollTaskFrom, reject, reject, removeShutdownHook, removeTask, runAllTasks, runAllTasks, runAllTasksFrom, runScheduledAndExecutorTasks, shutdown, shutdownGracefully, takeTask, terminationFuture, threadProperties, updateLastExecutionTime, wakesUpForTask

Methods inherited from class io.netty.util.concurrent.AbstractScheduledEventExecutor

cancelScheduledTasks, deadlineToDelayNanos, getCurrentTimeNanos, hasScheduledTasks, initialNanoTime, nanoTime, nextScheduledTaskDeadlineNanos, nextScheduledTaskNano, pollScheduledTask, pollScheduledTask, schedule, schedule, scheduleAtFixedRate, scheduleWithFixedDelay, validateScheduled

Methods inherited from class io.netty.util.concurrent.AbstractEventExecutor

inEventLoop, iterator, newFailedFuture, newProgressivePromise, newPromise, newSucceededFuture, newTaskFor, newTaskFor, runTask, safeExecute, shutdownGracefully, shutdownNow, submit, submit, submit

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface io.netty.util.concurrent.EventExecutor

inEventLoop, inEventLoop, newFailedFuture, newProgressivePromise, newPromise, newSucceededFuture

Methods inherited from interface io.netty.util.concurrent.EventExecutorGroup

isShuttingDown, iterator, schedule, schedule, scheduleAtFixedRate, scheduleWithFixedDelay, shutdown, shutdownGracefully, shutdownGracefully, shutdownNow, submit, submit, submit, terminationFuture

Methods inherited from interface java.util.concurrent.Executor

execute

Methods inherited from interface java.util.concurrent.ExecutorService

awaitTermination, close, invokeAll, invokeAll, invokeAny, invokeAny, isShutdown, isTerminated

Methods inherited from interface java.lang.Iterable

forEach, spliterator

Field Details

logger

private static final InternalLogger logger

CLEANUP_INTERVAL

private static final int CLEANUP_INTERVAL

See Also:

• Constant Field Values

DISABLE_KEY_SET_OPTIMIZATION

private static final boolean DISABLE_KEY_SET_OPTIMIZATION

MIN_PREMATURE_SELECTOR_RETURNS

private static final int MIN_PREMATURE_SELECTOR_RETURNS

See Also:

• Constant Field Values

SELECTOR_AUTO_REBUILD_THRESHOLD

private static final int SELECTOR_AUTO_REBUILD_THRESHOLD

selectNowSupplier

private final IntSupplier selectNowSupplier

selector

private Selector selector

The NIO Selector.

unwrappedSelector

private Selector unwrappedSelector

selectedKeys

private SelectedSelectionKeySet selectedKeys

provider

private final SelectorProvider provider

AWAKE

private static final long AWAKE

See Also:

• Constant Field Values

NONE

private static final long NONE

See Also:

• Constant Field Values

nextWakeupNanos

private final AtomicLong nextWakeupNanos

selectStrategy

private final SelectStrategy selectStrategy

ioRatio

private volatile int ioRatio

cancelledKeys

private int cancelledKeys

needsToSelectAgain

private boolean needsToSelectAgain

Constructor Details

NioEventLoop

NioEventLoop(NioEventLoopGroup parent,
 Executor executor,
 SelectorProvider selectorProvider,
 SelectStrategy strategy,
 RejectedExecutionHandler rejectedExecutionHandler,
 EventLoopTaskQueueFactory taskQueueFactory,
 EventLoopTaskQueueFactory tailTaskQueueFactory)

Method Details

newTaskQueue

private static Queue<Runnable> newTaskQueue(EventLoopTaskQueueFactory queueFactory)

openSelector

private NioEventLoop.SelectorTuple openSelector()

selectorProvider

public SelectorProvider selectorProvider()

Returns the SelectorProvider used by this NioEventLoop to obtain the Selector.

newTaskQueue

protected Queue<Runnable> newTaskQueue(int maxPendingTasks)

Description copied from class: SingleThreadEventExecutor

Create a new Queue which will holds the tasks to execute. This default implementation will return a LinkedBlockingQueue but if your sub-class of SingleThreadEventExecutor will not do any blocking calls on the this Queue it may make sense to @Override this and return some more performant implementation that does not support blocking operations at all.

Overrides:

newTaskQueue in class SingleThreadEventExecutor

newTaskQueue0

private static Queue<Runnable> newTaskQueue0(int maxPendingTasks)

register

public void register(SelectableChannel ch,
 int interestOps,
 NioTask<?> task)

Registers an arbitrary SelectableChannel, not necessarily created by Netty, to the Selector of this event loop. Once the specified SelectableChannel is registered, the specified task will be executed by this event loop when the SelectableChannel is ready.

register0

private void register0(SelectableChannel ch,
 int interestOps,
 NioTask<?> task)

getIoRatio

public int getIoRatio()

Returns the percentage of the desired amount of time spent for I/O in the event loop.

setIoRatio

public void setIoRatio(int ioRatio)

Sets the percentage of the desired amount of time spent for I/O in the event loop. Value range from 1-100. The default value is 50, which means the event loop will try to spend the same amount of time for I/O as for non-I/O tasks. The lower the number the more time can be spent on non-I/O tasks. If value set to 100, this feature will be disabled and event loop will not attempt to balance I/O and non-I/O tasks.

rebuildSelector

public void rebuildSelector()

Replaces the current Selector of this event loop with newly created Selectors to work around the infamous epoll 100% CPU bug.

registeredChannels

public int registeredChannels()

Description copied from class: SingleThreadEventLoop

Returns the number of Channels registered with this EventLoop or -1 if operation is not supported. The returned value is not guaranteed to be exact accurate and should be viewed as a best effort.

Overrides:

registeredChannels in class SingleThreadEventLoop

registeredChannelsIterator

public Iterator<Channel> registeredChannelsIterator()

Overrides:

registeredChannelsIterator in class SingleThreadEventLoop

Returns:

read-only iterator of active Channels registered with this EventLoop. The returned value is not guaranteed to be exact accurate and should be viewed as a best effort. This method is expected to be called from within event loop.

rebuildSelector0

private void rebuildSelector0()

run

protected void run()

Description copied from class: SingleThreadEventExecutor

Run the tasks in the SingleThreadEventExecutor.taskQueue

Specified by:

run in class SingleThreadEventExecutor

selectReturnPrematurely

private boolean selectReturnPrematurely(int selectCnt,
 boolean ranTasks,
 int strategy)

unexpectedSelectorWakeup

private boolean unexpectedSelectorWakeup(int selectCnt)

handleLoopException

private static void handleLoopException(Throwable t)

processSelectedKeys

private void processSelectedKeys()

cleanup

protected void cleanup()

Description copied from class: SingleThreadEventExecutor

Do nothing, sub-classes may override

Overrides:

cleanup in class SingleThreadEventExecutor

cancel

void cancel(SelectionKey key)

processSelectedKeysPlain

private void processSelectedKeysPlain(Set<SelectionKey> selectedKeys)

processSelectedKeysOptimized

private void processSelectedKeysOptimized()

processSelectedKey

private void processSelectedKey(SelectionKey k,
 AbstractNioChannel ch)

processSelectedKey

private static void processSelectedKey(SelectionKey k,
 NioTask<SelectableChannel> task)

closeAll

private void closeAll()

invokeChannelUnregistered

private static void invokeChannelUnregistered(NioTask<SelectableChannel> task,
 SelectionKey k,
 Throwable cause)

wakeup

protected void wakeup(boolean inEventLoop)

Overrides:

wakeup in class SingleThreadEventExecutor

beforeScheduledTaskSubmitted

protected boolean beforeScheduledTaskSubmitted(long deadlineNanos)

Description copied from class: AbstractScheduledEventExecutor

Called from arbitrary non-EventExecutor threads prior to scheduled task submission. Returns true if the EventExecutor thread should be woken immediately to process the scheduled task (if not already awake).

If false is returned, AbstractScheduledEventExecutor.afterScheduledTaskSubmitted(long) will be called with the same value after the scheduled task is enqueued, providing another opportunity to wake the EventExecutor thread if required.

Overrides:

beforeScheduledTaskSubmitted in class AbstractScheduledEventExecutor

Parameters:

deadlineNanos - deadline of the to-be-scheduled task relative to AbstractScheduledEventExecutor.getCurrentTimeNanos()

Returns:

true if the EventExecutor thread should be woken, false otherwise

afterScheduledTaskSubmitted

protected boolean afterScheduledTaskSubmitted(long deadlineNanos)

Description copied from class: AbstractScheduledEventExecutor

See AbstractScheduledEventExecutor.beforeScheduledTaskSubmitted(long). Called only after that method returns false.

Overrides:

afterScheduledTaskSubmitted in class AbstractScheduledEventExecutor

Parameters:

deadlineNanos - relative to AbstractScheduledEventExecutor.getCurrentTimeNanos()

Returns:

true if the EventExecutor thread should be woken, false otherwise

unwrappedSelector

Selector unwrappedSelector()

selectNow

int selectNow()
       throws IOException

Throws:

IOException

select

private int select(long deadlineNanos)
            throws IOException

Throws:

IOException

selectAgain

private void selectAgain()