Class SingleThreadIoEventLoop

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.SingleThreadIoEventLoop

All Implemented Interfaces:

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

Direct Known Subclasses:

EpollEventLoop, NioEventLoop

public class SingleThreadIoEventLoop
extends SingleThreadEventLoop
implements IoEventLoop

IoEventLoop implementation that execute all its submitted tasks in a single thread using the provided IoHandler.

Nested Class Summary

Nested classes/interfaces inherited from class SingleThreadEventLoop

SingleThreadEventLoop.ChannelsReadOnlyIterator<T>

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 inherited from class SingleThreadEventLoop

DEFAULT_MAX_PENDING_TASKS

Modifier and Type	Field	Description
protected static final int	DEFAULT_MAX_PENDING_TASKS

Constructor Summary

Constructors

Modifier	Constructor	Description
	SingleThreadIoEventLoop(IoEventLoopGroup parent, Executor executor, IoHandlerFactory ioHandlerFactory)	Creates a new instance
	SingleThreadIoEventLoop(IoEventLoopGroup parent, Executor executor, IoHandlerFactory ioHandlerFactory, int maxPendingTasks, RejectedExecutionHandler rejectedExecutionHandler, long maxTaskProcessingQuantumMs)	Creates a new instance
protected	SingleThreadIoEventLoop(IoEventLoopGroup parent, Executor executor, IoHandlerFactory ioHandlerFactory, Queue<Runnable> taskQueue, Queue<Runnable> tailTaskQueue, RejectedExecutionHandler rejectedExecutionHandler)	Creates a new instance
	SingleThreadIoEventLoop(IoEventLoopGroup parent, ThreadFactory threadFactory, IoHandlerFactory ioHandlerFactory)	Creates a new instance
	SingleThreadIoEventLoop(IoEventLoopGroup parent, ThreadFactory threadFactory, IoHandlerFactory ioHandlerFactory, int maxPendingTasks, RejectedExecutionHandler rejectedExecutionHandler, long maxTaskProcessingQuantumMs)	Creates a new instance

Method Summary

Modifier and Type	Method	Description
protected boolean	canSuspend(int state)	Returns true if this SingleThreadEventExecutor can be suspended at the moment, false otherwise.
protected final void	cleanup()	Do nothing, sub-classes may override
protected int	getNumOfRegisteredChannels()	Returns the number of registered channels for auto-scaling related decisions.
protected final IoHandler	ioHandler()
boolean	isCompatible(Class<? extends IoHandle> handleType)	Returns true if the given type is compatible with this IoEventLoopGroup and so can be registered to the contained IoEventLoops, false otherwise.
boolean	isIoType(Class<? extends IoHandler> handlerType)	Returns true if the given IoHandler type is used by this IoEventLoopGroup, false otherwise.
protected Queue<Runnable>	newTaskQueue(int maxPendingTasks)	Create a new Queue which will holds the tasks to execute.
protected static Queue<Runnable>	newTaskQueue0(int maxPendingTasks)
IoEventLoop	next()	Returns one of the EventExecutors managed by this EventExecutorGroup.
final Future<IoRegistration>	register(IoHandle handle)	Register the IoHandle to the EventLoop for I/O processing.
protected void	run()	Runs the task-processing loop until SingleThreadEventExecutor.confirmShutdown() returns true.
protected int	runIo()	Called when IO will be processed for all the IoHandles on this SingleThreadIoEventLoop.
protected final void	wakeup(boolean inEventLoop)

Methods inherited from class SingleThreadEventLoop

afterRunningAllTasks, executeAfterEventLoopIteration, hasTasks, parent, pendingTasks, register, register, register, registeredChannels, registeredChannelsIterator

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

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	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).
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 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 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.

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 IoEventLoopGroup

register, register

Modifier and Type	Method	Description
default ChannelFuture	register(Channel channel)	Deprecated. Use IoEventLoopGroup.register(IoHandle)
default ChannelFuture	register(ChannelPromise promise)	Deprecated. Use IoEventLoopGroup.register(IoHandle)

Methods inherited from interface Iterable

forEach, spliterator

Constructor Details

SingleThreadIoEventLoop

public SingleThreadIoEventLoop(IoEventLoopGroup parent,
 ThreadFactory threadFactory,
 IoHandlerFactory ioHandlerFactory)

Creates a new instance

Parameters:

parent - the parent that holds this IoEventLoop.

threadFactory - the ThreadFactory that is used to create the underlying Thread.

ioHandlerFactory - the IoHandlerFactory that should be used to obtain IoHandler to handle IO.

SingleThreadIoEventLoop

public SingleThreadIoEventLoop(IoEventLoopGroup parent,
 Executor executor,
 IoHandlerFactory ioHandlerFactory)

Creates a new instance

Parameters:

parent - the parent that holds this IoEventLoop.

executor - the Executor that is used for dispatching the work.

ioHandlerFactory - the IoHandlerFactory that should be used to obtain IoHandler to handle IO.

SingleThreadIoEventLoop

public SingleThreadIoEventLoop(IoEventLoopGroup parent,
 ThreadFactory threadFactory,
 IoHandlerFactory ioHandlerFactory,
 int maxPendingTasks,
 RejectedExecutionHandler rejectedExecutionHandler,
 long maxTaskProcessingQuantumMs)

Creates a new instance

Parameters:

parent - the parent that holds this IoEventLoop.

threadFactory - the ThreadFactory that is used to create the underlying Thread.

ioHandlerFactory - the IoHandlerFactory that should be used to obtain IoHandler to handle IO.

maxPendingTasks - the maximum pending tasks that are allowed before RejectedExecutionHandler.rejected(Runnable, SingleThreadEventExecutor) is called to handle it.

rejectedExecutionHandler - the RejectedExecutionHandler that handles when more tasks are added then allowed per maxPendingTasks.

maxTaskProcessingQuantumMs - the maximum number of milliseconds that will be spent to run tasks before trying to run IO again.

SingleThreadIoEventLoop

public SingleThreadIoEventLoop(IoEventLoopGroup parent,
 Executor executor,
 IoHandlerFactory ioHandlerFactory,
 int maxPendingTasks,
 RejectedExecutionHandler rejectedExecutionHandler,
 long maxTaskProcessingQuantumMs)

Creates a new instance

Parameters:

parent - the parent that holds this IoEventLoop.

ioHandlerFactory - the IoHandlerFactory that should be used to obtain IoHandler to handle IO.

maxPendingTasks - the maximum pending tasks that are allowed before RejectedExecutionHandler.rejected(Runnable, SingleThreadEventExecutor) is called to handle it.

rejectedExecutionHandler - the RejectedExecutionHandler that handles when more tasks are added then allowed per maxPendingTasks.

maxTaskProcessingQuantumMs - the maximum number of milliseconds that will be spent to run tasks before trying to run IO again.

SingleThreadIoEventLoop

protected SingleThreadIoEventLoop(IoEventLoopGroup parent,
 Executor executor,
 IoHandlerFactory ioHandlerFactory,
 Queue<Runnable> taskQueue,
 Queue<Runnable> tailTaskQueue,
 RejectedExecutionHandler rejectedExecutionHandler)

Creates a new instance

Parameters:

parent - the parent that holds this IoEventLoop.

executor - the Executor that is used for dispatching the work.

ioHandlerFactory - the IoHandlerFactory that should be used to obtain IoHandler to handle IO.

taskQueue - the Queue used for storing pending tasks.

tailTaskQueue - the Queue used for storing tail pending tasks.

rejectedExecutionHandler - the RejectedExecutionHandler that handles when more tasks are added then allowed.

Method Details

run

protected void run()

Description copied from class: SingleThreadEventExecutor

Runs the task-processing loop until SingleThreadEventExecutor.confirmShutdown() returns true.

Implementations must not let a Throwable thrown by a task escape this method: any uncaught Throwable terminates the executor (logged at WARN and surfaced via SingleThreadEventExecutor.terminationFuture()), at which point every Channel registered with this executor stops processing I/O and new task submissions are rejected. The supplied helpers - SingleThreadEventExecutor.runAllTasks(), SingleThreadEventExecutor.runAllTasks(long), and AbstractEventExecutor.safeExecute(Runnable) - catch Throwable for you; custom loops built on SingleThreadEventExecutor.pollTask() or SingleThreadEventExecutor.takeTask() are responsible for wrapping each task invocation accordingly.

Specified by:

run in class SingleThreadEventExecutor

ioHandler

protected final IoHandler ioHandler()

canSuspend

protected boolean canSuspend(int state)

Description copied from class: SingleThreadEventExecutor

Returns true if this SingleThreadEventExecutor can be suspended at the moment, false otherwise. Subclasses might override this method to add extra checks.

Overrides:

canSuspend in class SingleThreadEventExecutor

Parameters:

state - the current internal state of the SingleThreadEventExecutor.

Returns:

if suspension is possible at the moment.

runIo

protected int runIo()

Called when IO will be processed for all the IoHandles on this SingleThreadIoEventLoop. This method returns the number of IoHandles for which IO was processed. This method must be called from the EventLoop thread.

next

public IoEventLoop 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

Specified by:

next in interface IoEventLoop

Specified by:

next in interface IoEventLoopGroup

Overrides:

next in class SingleThreadEventLoop

register

public final Future<IoRegistration> register(IoHandle handle)

Description copied from interface: IoEventLoop

Register the IoHandle to the EventLoop for I/O processing.

Specified by:

register in interface IoEventLoop

Specified by:

register in interface IoEventLoopGroup

Parameters:

handle - the IoHandle to register.

Returns:

the Future that is notified once the operations completes.

getNumOfRegisteredChannels

protected int getNumOfRegisteredChannels()

Description copied from class: SingleThreadEventExecutor

Returns the number of registered channels for auto-scaling related decisions. This is intended to be used by MultithreadEventExecutorGroup for dynamic scaling.

Overrides:

getNumOfRegisteredChannels in class SingleThreadEventExecutor

Returns:

The number of registered channels, or -1 if not applicable.

wakeup

protected final void wakeup(boolean inEventLoop)

Overrides:

wakeup in class SingleThreadEventExecutor

cleanup

protected final void cleanup()

Description copied from class: SingleThreadEventExecutor

Do nothing, sub-classes may override

Overrides:

cleanup in class SingleThreadEventExecutor

isCompatible

public boolean isCompatible(Class<? extends IoHandle> handleType)

Description copied from interface: IoEventLoopGroup

Returns true if the given type is compatible with this IoEventLoopGroup and so can be registered to the contained IoEventLoops, false otherwise.

Specified by:

isCompatible in interface IoEventLoop

Specified by:

isCompatible in interface IoEventLoopGroup

Parameters:

handleType - the type of the IoHandle.

Returns:

if compatible of not.

isIoType

public boolean isIoType(Class<? extends IoHandler> handlerType)

Description copied from interface: IoEventLoopGroup

Returns true if the given IoHandler type is used by this IoEventLoopGroup, false otherwise.

Specified by:

isIoType in interface IoEventLoop

Specified by:

isIoType in interface IoEventLoopGroup

Parameters:

handlerType - the type of the IoHandler.

Returns:

if used or not.

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

protected static Queue<Runnable> newTaskQueue0(int maxPendingTasks)