Class SingleThreadEventLoop

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

All Implemented Interfaces:

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

Direct Known Subclasses:

DefaultEventLoop, SingleThreadIoEventLoop, ThreadPerChannelEventLoop

public abstract class SingleThreadEventLoop
extends SingleThreadEventExecutor
implements EventLoop

Abstract base class for EventLoops that execute all its submitted tasks in a single thread.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
protected static final class	SingleThreadEventLoop.ChannelsReadOnlyIterator<T extends Channel>

Nested classes/interfaces inherited from class SingleThreadEventExecutor

SingleThreadEventExecutor.NonWakeupRunnable

Modifier and Type	Class	Description
protected static interface	SingleThreadEventExecutor.NonWakeupRunnable	Deprecated. override SingleThreadEventExecutor.wakesUpForTask(Runnable) to re-create this behaviour

Nested classes/interfaces inherited from class AbstractEventExecutor

AbstractEventExecutor.LazyRunnable

Modifier and Type	Class	Description
static interface	AbstractEventExecutor.LazyRunnable	Deprecated. override SingleThreadEventExecutor.wakesUpForTask(Runnable) to re-create this behaviour

Field Summary

Fields

Modifier and Type	Field	Description
protected static final int	DEFAULT_MAX_PENDING_TASKS

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	SingleThreadEventLoop(EventLoopGroup parent, Executor executor, boolean addTaskWakesUp)
protected	SingleThreadEventLoop(EventLoopGroup parent, Executor executor, boolean addTaskWakesUp, boolean supportSuspension)
protected	SingleThreadEventLoop(EventLoopGroup parent, Executor executor, boolean addTaskWakesUp, boolean supportSuspension, int maxPendingTasks, RejectedExecutionHandler rejectedExecutionHandler)
protected	SingleThreadEventLoop(EventLoopGroup parent, Executor executor, boolean addTaskWakesUp, boolean supportSuspension, Queue<Runnable> taskQueue, Queue<Runnable> tailTaskQueue, RejectedExecutionHandler rejectedExecutionHandler)
protected	SingleThreadEventLoop(EventLoopGroup parent, Executor executor, boolean addTaskWakesUp, int maxPendingTasks, RejectedExecutionHandler rejectedExecutionHandler)
protected	SingleThreadEventLoop(EventLoopGroup parent, Executor executor, boolean addTaskWakesUp, Queue<Runnable> taskQueue, Queue<Runnable> tailTaskQueue, RejectedExecutionHandler rejectedExecutionHandler)
protected	SingleThreadEventLoop(EventLoopGroup parent, ThreadFactory threadFactory, boolean addTaskWakesUp)
protected	SingleThreadEventLoop(EventLoopGroup parent, ThreadFactory threadFactory, boolean addTaskWakesUp, boolean supportSuspension)
protected	SingleThreadEventLoop(EventLoopGroup parent, ThreadFactory threadFactory, boolean addTaskWakesUp, boolean supportSuspension, int maxPendingTasks, RejectedExecutionHandler rejectedExecutionHandler)
protected	SingleThreadEventLoop(EventLoopGroup parent, ThreadFactory threadFactory, boolean addTaskWakesUp, int maxPendingTasks, RejectedExecutionHandler rejectedExecutionHandler)

Method Summary

Modifier and Type	Method	Description
protected void	afterRunningAllTasks()	Invoked before returning from SingleThreadEventExecutor.runAllTasks() and SingleThreadEventExecutor.runAllTasks(long).
final void	executeAfterEventLoopIteration(Runnable task)	Adds a task to be run once at the end of next (or current) eventloop iteration.
protected boolean	hasTasks()
EventLoop	next()	Returns one of the EventExecutors managed by this EventExecutorGroup.
EventLoopGroup	parent()	Return the EventExecutorGroup which is the parent of this EventExecutor,
int	pendingTasks()	Return the number of tasks that are pending for processing.
ChannelFuture	register(Channel channel)	Register a Channel with this EventLoop.
ChannelFuture	register(ChannelPromise promise)	Register a Channel with this EventLoop using a ChannelFuture.
ChannelFuture	register(Channel channel, ChannelPromise promise)	Deprecated.
int	registeredChannels()	Returns the number of Channels registered with this EventLoop or -1 if operation is not supported.
Iterator<Channel>	registeredChannelsIterator()

Methods inherited from class SingleThreadEventExecutor

addShutdownHook, addTask, awaitTermination, canSuspend, canSuspend, cleanup, confirmShutdown, deadlineNanos, delayNanos, execute, getAndIncrementBusyCycles, getAndIncrementIdleCycles, getAndResetAccumulatedActiveTimeNanos, getLastActivityTimeNanos, getNumOfRegisteredChannels, inEventLoop, interruptThread, invokeAll, invokeAll, invokeAny, invokeAny, isShutdown, isShuttingDown, isSuspended, isSuspensionSupported, isTerminated, lazyExecute, newTaskQueue, newTaskQueue, peekTask, pollTask, pollTaskFrom, reject, reject, removeShutdownHook, removeTask, reportActiveIoTime, resetBusyCycles, resetIdleCycles, run, runAllTasks, runAllTasks, runAllTasksFrom, runScheduledAndExecutorTasks, shutdown, shutdownGracefully, takeTask, terminationFuture, threadProperties, trySuspend, updateLastExecutionTime, wakesUpForTask, wakeup

Modifier and Type	Method	Description
void	addShutdownHook(Runnable task)	Add a Runnable which will be executed on shutdown of this instance
protected void	addTask(Runnable task)	Add a task to the task queue, or throws a RejectedExecutionException if this instance was shutdown before.
boolean	awaitTermination(long timeout, TimeUnit unit)
protected boolean	canSuspend()	Returns true if this SingleThreadEventExecutor can be suspended at the moment, false otherwise.
protected boolean	canSuspend(int state)	Returns true if this SingleThreadEventExecutor can be suspended at the moment, false otherwise.
protected void	cleanup()	Do nothing, sub-classes may override
protected boolean	confirmShutdown()	Confirm that the shutdown if the instance should be done now!
protected long	deadlineNanos()	Returns the absolute point in time (relative to AbstractScheduledEventExecutor.getCurrentTimeNanos()) at which the next closest scheduled task should run.
protected long	delayNanos(long currentTimeNanos)	Returns the amount of time left until the scheduled task with the closest dead line is executed.
void	execute(Runnable task)
protected int	getAndIncrementBusyCycles()	Atomically increments the counter for consecutive monitor cycles where utilization was above the scale-up threshold.
protected int	getAndIncrementIdleCycles()	Atomically increments the counter for consecutive monitor cycles where utilization was below the scale-down threshold.
protected long	getAndResetAccumulatedActiveTimeNanos()	Returns the accumulated active time since the last call and resets the counter.
protected long	getLastActivityTimeNanos()	Returns the timestamp of the last known activity (tasks + I/O).
protected int	getNumOfRegisteredChannels()	Returns the number of registered channels for auto-scaling related decisions.
boolean	inEventLoop(Thread thread)	Return true if the given Thread is executed in the event loop, false otherwise.
protected void	interruptThread()	Interrupt the current running Thread.
<T> List<Future<T>>	invokeAll(Collection<? extends Callable<T>> tasks)
<T> List<Future<T>>	invokeAll(Collection<? extends Callable<T>> tasks, long timeout, TimeUnit unit)
<T> T	invokeAny(Collection<? extends Callable<T>> tasks)
<T> T	invokeAny(Collection<? extends Callable<T>> tasks, long timeout, TimeUnit unit)
boolean	isShutdown()
boolean	isShuttingDown()	Returns true if and only if all EventExecutors managed by this EventExecutorGroup are being shut down gracefully or was shut down.
boolean	isSuspended()	Returns true if the EventExecutor is considered suspended.
protected boolean	isSuspensionSupported()	Returns true if this SingleThreadEventExecutor supports suspension.
boolean	isTerminated()
void	lazyExecute(Runnable task)	Like Executor.execute(Runnable) but does not guarantee the task will be run until either a non-lazy task is executed or the executor is shut down.
protected Queue<Runnable>	newTaskQueue()	Deprecated. Please use and override SingleThreadEventExecutor.newTaskQueue(int).
protected Queue<Runnable>	newTaskQueue(int maxPendingTasks)	Create a new Queue which will holds the tasks to execute.
protected Runnable	peekTask()
protected Runnable	pollTask()
protected static Runnable	pollTaskFrom(Queue<Runnable> taskQueue)
protected static void	reject()
protected final void	reject(Runnable task)	Offers the task to the associated RejectedExecutionHandler.
void	removeShutdownHook(Runnable task)	Remove a previous added Runnable as a shutdown hook
protected boolean	removeTask(Runnable task)
protected void	reportActiveIoTime(long nanos)	Adds the given duration to the total active time for the current measurement window.
protected void	resetBusyCycles()	Resets the counter for consecutive busy cycles to zero.
protected void	resetIdleCycles()	Resets the counter for consecutive idle cycles to zero.
protected abstract void	run()	Runs the task-processing loop until SingleThreadEventExecutor.confirmShutdown() returns true.
protected boolean	runAllTasks()	Poll all tasks from the task queue and run them via Runnable.run() method.
protected boolean	runAllTasks(long timeoutNanos)	Poll all tasks from the task queue and run them via Runnable.run() method.
protected final boolean	runAllTasksFrom(Queue<Runnable> taskQueue)	Runs all tasks from the passed taskQueue.
protected final boolean	runScheduledAndExecutorTasks(int maxDrainAttempts)	Execute all expired scheduled tasks and all current tasks in the executor queue until both queues are empty, or maxDrainAttempts has been exceeded.
void	shutdown()	Deprecated.
Future<?>	shutdownGracefully(long quietPeriod, long timeout, TimeUnit unit)	Signals this executor that the caller wants the executor to be shut down.
protected Runnable	takeTask()	Take the next Runnable from the task queue and so will block if no task is currently present.
Future<?>	terminationFuture()	Returns the Future which is notified when all EventExecutors managed by this EventExecutorGroup have been terminated.
final ThreadProperties	threadProperties()	Returns the ThreadProperties of the Thread that powers the SingleThreadEventExecutor.
boolean	trySuspend()	Try to suspend this EventExecutor and return true if suspension was successful.
protected void	updateLastExecutionTime()	Updates the internal timestamp that tells when a submitted task was executed most recently.
protected boolean	wakesUpForTask(Runnable task)	Can be overridden to control which tasks require waking the EventExecutor thread if it is waiting so that they can be run immediately.
protected void	wakeup(boolean inEventLoop)

Methods inherited from class AbstractScheduledEventExecutor

afterScheduledTaskSubmitted, beforeScheduledTaskSubmitted, cancelScheduledTasks, deadlineToDelayNanos, delayNanos, fetchFromScheduledTaskQueue, getCurrentTimeNanos, hasScheduledTasks, initialNanoTime, nanoTime, nextScheduledTaskDeadlineNanos, nextScheduledTaskNano, pollScheduledTask, pollScheduledTask, schedule, schedule, scheduleAtFixedRate, scheduleWithFixedDelay, ticker, validateScheduled

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.
protected void	cancelScheduledTasks()	Cancel all scheduled tasks.
protected static long	deadlineToDelayNanos(long deadlineNanos)	Deprecated. Use AbstractScheduledEventExecutor.ticker() instead
protected long	delayNanos(long currentTimeNanos, long scheduledPurgeInterval)	Returns the amount of time left until the scheduled task with the closest dead line is executed.
protected boolean	fetchFromScheduledTaskQueue(Queue<Runnable> taskQueue)	Fetch scheduled tasks from the internal queue and add these to the given Queue.
protected long	getCurrentTimeNanos()	Deprecated. Please use (or override) AbstractScheduledEventExecutor.ticker() instead.
protected final boolean	hasScheduledTasks()	Returns true if a scheduled task is ready for processing.
protected static long	initialNanoTime()	Deprecated. Use AbstractScheduledEventExecutor.ticker() instead
protected static long	nanoTime()	Deprecated. Use the non-static AbstractScheduledEventExecutor.ticker() instead.
protected final long	nextScheduledTaskDeadlineNanos()	Return the deadline (in nanoseconds) when the next scheduled task is ready to be run or -1 if no task is scheduled.
protected final long	nextScheduledTaskNano()	Return the nanoseconds until the next scheduled task is ready to be run or -1 if no task is scheduled.
protected final Runnable	pollScheduledTask()
protected final Runnable	pollScheduledTask(long nanoTime)	Return the Runnable which is ready to be executed with the given nanoTime.
ScheduledFuture<?>	schedule(Runnable command, long delay, TimeUnit unit)
<V> ScheduledFuture<V>	schedule(Callable<V> callable, long delay, TimeUnit unit)
ScheduledFuture<?>	scheduleAtFixedRate(Runnable command, long initialDelay, long period, TimeUnit unit)
ScheduledFuture<?>	scheduleWithFixedDelay(Runnable command, long initialDelay, long delay, TimeUnit unit)
Ticker	ticker()	The ticker for this executor.
protected void	validateScheduled(long amount, TimeUnit unit)	Deprecated. will be removed in the future.

Methods inherited from class AbstractEventExecutor

iterator, newTaskFor, newTaskFor, runTask, safeExecute, shutdownGracefully, shutdownNow, submit, submit, submit

Modifier and Type	Method	Description
Iterator<EventExecutor>	iterator()
protected final <T> RunnableFuture<T>	newTaskFor(Runnable runnable, T value)
protected final <T> RunnableFuture<T>	newTaskFor(Callable<T> callable)
protected static void	runTask(Runnable task)
protected static void	safeExecute(Runnable task)	Try to execute the given Runnable and just log if it throws a Throwable.
Future<?>	shutdownGracefully()	Shortcut method for EventExecutorGroup.shutdownGracefully(long, long, TimeUnit) with sensible default values.
List<Runnable>	shutdownNow()	Deprecated. EventExecutorGroup.shutdownGracefully(long, long, TimeUnit) or AbstractEventExecutor.shutdownGracefully() instead.
Future<?>	submit(Runnable task)
<T> Future<T>	submit(Runnable task, T result)
<T> Future<T>	submit(Callable<T> task)

Methods inherited from class Object

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

Methods inherited from interface EventExecutor

inEventLoop, isExecutorThread, newFailedFuture, newProgressivePromise, newPromise, newSucceededFuture

Modifier and Type	Method	Description
default boolean	inEventLoop()	Calls EventExecutor.inEventLoop(Thread) with Thread.currentThread() as argument
default boolean	isExecutorThread(Thread thread)	Return true if the given Thread is used by this ThreadAwareExecutor to execute work.
default <V> Future<V>	newFailedFuture(Throwable cause)	Create a new Future which is marked as failed already.
default <V> ProgressivePromise<V>	newProgressivePromise()	Create a new ProgressivePromise.
default <V> Promise<V>	newPromise()	Return a new Promise.
default <V> Future<V>	newSucceededFuture(V result)	Create a new Future which is marked as succeeded already.

Methods inherited from interface Iterable

forEach, spliterator

Field Details

DEFAULT_MAX_PENDING_TASKS

protected static final int DEFAULT_MAX_PENDING_TASKS

Constructor Details

SingleThreadEventLoop

protected SingleThreadEventLoop(EventLoopGroup parent,
 ThreadFactory threadFactory,
 boolean addTaskWakesUp)

SingleThreadEventLoop

protected SingleThreadEventLoop(EventLoopGroup parent,
 ThreadFactory threadFactory,
 boolean addTaskWakesUp,
 boolean supportSuspension)

SingleThreadEventLoop

protected SingleThreadEventLoop(EventLoopGroup parent,
 Executor executor,
 boolean addTaskWakesUp)

SingleThreadEventLoop

protected SingleThreadEventLoop(EventLoopGroup parent,
 Executor executor,
 boolean addTaskWakesUp,
 boolean supportSuspension)

SingleThreadEventLoop

protected SingleThreadEventLoop(EventLoopGroup parent,
 ThreadFactory threadFactory,
 boolean addTaskWakesUp,
 int maxPendingTasks,
 RejectedExecutionHandler rejectedExecutionHandler)

SingleThreadEventLoop

protected SingleThreadEventLoop(EventLoopGroup parent,
 ThreadFactory threadFactory,
 boolean addTaskWakesUp,
 boolean supportSuspension,
 int maxPendingTasks,
 RejectedExecutionHandler rejectedExecutionHandler)

SingleThreadEventLoop

protected SingleThreadEventLoop(EventLoopGroup parent,
 Executor executor,
 boolean addTaskWakesUp,
 int maxPendingTasks,
 RejectedExecutionHandler rejectedExecutionHandler)

SingleThreadEventLoop

protected SingleThreadEventLoop(EventLoopGroup parent,
 Executor executor,
 boolean addTaskWakesUp,
 boolean supportSuspension,
 int maxPendingTasks,
 RejectedExecutionHandler rejectedExecutionHandler)

SingleThreadEventLoop

protected SingleThreadEventLoop(EventLoopGroup parent,
 Executor executor,
 boolean addTaskWakesUp,
 Queue<Runnable> taskQueue,
 Queue<Runnable> tailTaskQueue,
 RejectedExecutionHandler rejectedExecutionHandler)

SingleThreadEventLoop

protected SingleThreadEventLoop(EventLoopGroup parent,
 Executor executor,
 boolean addTaskWakesUp,
 boolean supportSuspension,
 Queue<Runnable> taskQueue,
 Queue<Runnable> tailTaskQueue,
 RejectedExecutionHandler rejectedExecutionHandler)

Method Details

parent

public EventLoopGroup parent()

Description copied from interface: EventExecutor

Return the EventExecutorGroup which is the parent of this EventExecutor,

Specified by:

parent in interface EventExecutor

Specified by:

parent in interface EventLoop

Overrides:

parent in class AbstractEventExecutor

next

public EventLoop next()

Description copied from interface: EventExecutorGroup

Returns one of the EventExecutors managed by this EventExecutorGroup.

Specified by:

next in interface EventExecutorGroup

Specified by:

next in interface EventLoopGroup

Overrides:

next in class AbstractEventExecutor

register

public ChannelFuture register(Channel channel)

Description copied from interface: EventLoopGroup

Register a Channel with this EventLoop. The returned ChannelFuture will get notified once the registration was complete.

Specified by:

register in interface EventLoopGroup

register

public ChannelFuture register(ChannelPromise promise)

Description copied from interface: EventLoopGroup

Register a Channel with this EventLoop using a ChannelFuture. The passed ChannelFuture will get notified once the registration was complete and also will get returned.

Specified by:

register in interface EventLoopGroup

register

@Deprecated
public ChannelFuture register(Channel channel,
 ChannelPromise promise)

Deprecated.

Description copied from interface: EventLoopGroup

Register a Channel with this EventLoop. The passed ChannelFuture will get notified once the registration was complete and also will get returned.

Specified by:

register in interface EventLoopGroup

executeAfterEventLoopIteration

public final void executeAfterEventLoopIteration(Runnable task)

Adds a task to be run once at the end of next (or current) eventloop iteration.

Parameters:

task - to be added.

afterRunningAllTasks

protected void afterRunningAllTasks()

Description copied from class: SingleThreadEventExecutor

Invoked before returning from SingleThreadEventExecutor.runAllTasks() and SingleThreadEventExecutor.runAllTasks(long).

Overrides:

afterRunningAllTasks in class SingleThreadEventExecutor

hasTasks

protected boolean hasTasks()

Overrides:

hasTasks in class SingleThreadEventExecutor

See Also:

• Collection.isEmpty()

pendingTasks

public int pendingTasks()

Description copied from class: SingleThreadEventExecutor

Return the number of tasks that are pending for processing.

Overrides:

pendingTasks in class SingleThreadEventExecutor

registeredChannels

@UnstableApi
public int registeredChannels()

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.

registeredChannelsIterator

@UnstableApi
public Iterator<Channel> registeredChannelsIterator()

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.

Throws:

UnsupportedOperationException - if operation is not supported by implementation.