org.dromara.hmily.xa.core.timer

类 HashedWheelTimer

java.lang.Object

org.dromara.hmily.xa.core.timer.HashedWheelTimer

所有已实现的接口:

Timer

public class HashedWheelTimer
extends Object
implements Timer

A Timer optimized for approximated I/O timeout scheduling.

Tick Duration

As described with 'approximated', this timer does not execute the scheduled TimerTask on time. HashedWheelTimer, on every tick, will check if there are any TimerTasks behind the schedule and execute them.

You can increase or decrease the accuracy of the execution timing by specifying smaller or larger tick duration in the constructor. In most network applications, I/O timeout does not need to be accurate. Therefore, the default tick duration is 100 milliseconds and you will not need to try different configurations in most cases.

Ticks per Wheel (Wheel Size)

HashedWheelTimer maintains a data structure called 'wheel'. To put simply, a wheel is a hash table of TimerTasks whose hash function is 'dead line of the task'. The default number of ticks per wheel (i.e. the size of the wheel) is 512. You could specify a larger value if you are going to schedule a lot of timeouts.

Do not create many instances.

HashedWheelTimer creates a new thread whenever it is instantiated and started. Therefore, you should make sure to create only one instance and share it across your application. One of the common mistakes, that makes your application unresponsive, is to create a new instance for every connection.

Implementation Details

HashedWheelTimer is based on George Varghese and Tony Lauck's paper, 'Hashed and Hierarchical Timing Wheels: data structures to efficiently implement a timer facility'. More comprehensive slides are located here.

构造器概要

构造器

构造器和说明
HashedWheelTimer(ThreadFactory threadFactory) 初始化一个环形时间执行器.
HashedWheelTimer(ThreadFactory threadFactory, long tickDuration, TimeUnit unit, int ticksPerWheel) 初始化一个环形时间执行器.

方法概要

限定符和类型	方法和说明
boolean	isStop() Is stop boolean.
Timeout	newTimeout(TimerTask task, long delay, TimeUnit unit) Schedules the specified TimerTask for one-time execution after the specified delay.
void	start() 启动任务.
Set<Timeout>	stop() Releases all resources acquired by this Timer and cancels all tasks which were scheduled but not executed yet.

从类继承的方法 java.lang.Object

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

构造器详细资料

HashedWheelTimer

public HashedWheelTimer(ThreadFactory threadFactory)

初始化一个环形时间执行器.

参数:

threadFactory - 线程初始化工厂；

HashedWheelTimer

public HashedWheelTimer(ThreadFactory threadFactory,
                        long tickDuration,
                        TimeUnit unit,
                        int ticksPerWheel)

初始化一个环形时间执行器.

参数:

threadFactory - 线程初始化工厂；

tickDuration - 持续执行时间；

unit - 时间单位；

ticksPerWheel - 时间分片数；

方法详细资料

start

public void start()

启动任务.

newTimeout

public Timeout newTimeout(TimerTask task,
                          long delay,
                          TimeUnit unit)

从接口复制的说明: Timer

Schedules the specified TimerTask for one-time execution after the specified delay.

指定者:

newTimeout 在接口中 Timer

参数:

task - timeTask

delay - delay time;

unit - time unit;

返回:

a handle which is associated with the specified task

stop

public Set<Timeout> stop()

从接口复制的说明: Timer

Releases all resources acquired by this Timer and cancels all tasks which were scheduled but not executed yet.

指定者:

stop 在接口中 Timer

返回:

the handles associated with the tasks which were canceled by this method

isStop

public boolean isStop()

从接口复制的说明: Timer

Is stop boolean.

指定者:

isStop 在接口中 Timer

返回:

the boolean