Package org.shoulder.monitor.concurrent

Class AutoScaleThreadPool

java.lang.Object

java.util.concurrent.AbstractExecutorService

java.util.concurrent.ThreadPoolExecutor

org.shoulder.monitor.concurrent.AutoScaleThreadPool

All Implemented Interfaces:

AutoCloseable, Executor, ExecutorService

public class AutoScaleThreadPool
extends ThreadPoolExecutor

可自动扩容、缩容核心线程数的线程池，（可更合理的利用线程资源、应对突发事件处理）适合平时节能模式处理，突然紧急情况下提前加速处理的场景

JDK 中实现的当且仅当任务队列满了时才会创建新线程，但如果这时候突发来多个任务，则导致任务很可能被拒绝 实际中应根据队列容量自动扩容线程数，如，当队列中任务数达到上限的 70%、80%、90%，则自动扩容线程，而不是满了之后才扩容，缓解大压力场景下触发

默认参数举例： - 执行前，若队列中任务数大于 75% 队列容量 且 threadSize 小于 maxSize，将线程数加一，默认冷却时间 5s - 执行后，若队列中任务数小于25% 队列容量 且 threadSize 小于 originCoreSize，将 core 线程数减少一，默认冷却时间 5s

动态设置参数实现： 对接配置中心 监控、告警实现： 对接 prometheus，过载告警 操作记录与审计： 对接日志中心，变更通知 https://tech.meituan.com/2020/04/02/java-pooling-pratice-in-meituan.html

Author:

lym

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static final class	AutoScaleThreadPool.ScaleRule	自动扩容、缩容规则 该类职责完全服务于外部类，故置为内部类

Nested classes/interfaces inherited from class java.util.concurrent.ThreadPoolExecutor

ThreadPoolExecutor.AbortPolicy, ThreadPoolExecutor.CallerRunsPolicy, ThreadPoolExecutor.DiscardOldestPolicy, ThreadPoolExecutor.DiscardPolicy

Constructor Summary

Constructors

Constructor	Description
AutoScaleThreadPool(int corePoolSize, int maximumPoolSize, long keepAliveTime, TimeUnit unit, BlockingQueue<Runnable> workQueue, RejectedExecutionHandler handler, AutoScaleThreadPool.ScaleRule scaleRule)	调用父类的构造方法，并初始化HashMap和线程池名称
AutoScaleThreadPool(int corePoolSize, int maximumPoolSize, long keepAliveTime, TimeUnit unit, BlockingQueue<Runnable> workQueue, ThreadFactory threadFactory, RejectedExecutionHandler handler, AutoScaleThreadPool.ScaleRule scaleRule)	调用父类的构造方法，并初始化HashMap和线程池名称
AutoScaleThreadPool(int corePoolSize, int maximumPoolSize, long keepAliveTime, TimeUnit unit, BlockingQueue<Runnable> workQueue, ThreadFactory threadFactory, AutoScaleThreadPool.ScaleRule scaleRule)	调用父类的构造方法，并初始化HashMap和线程池名称
AutoScaleThreadPool(int corePoolSize, int maximumPoolSize, long keepAliveTime, TimeUnit unit, BlockingQueue<Runnable> workQueue, AutoScaleThreadPool.ScaleRule scaleRule)	调用父类的构造方法，并初始化HashMap和线程池名称

Method Summary

Modifier and Type	Method	Description
protected void	afterExecute(Runnable r, Throwable t)
protected void	beforeExecute(Thread t, Runnable r)

Methods inherited from class java.util.concurrent.ThreadPoolExecutor

allowCoreThreadTimeOut, allowsCoreThreadTimeOut, awaitTermination, execute, finalize, getActiveCount, getCompletedTaskCount, getCorePoolSize, getKeepAliveTime, getLargestPoolSize, getMaximumPoolSize, getPoolSize, getQueue, getRejectedExecutionHandler, getTaskCount, getThreadFactory, isShutdown, isTerminated, isTerminating, prestartAllCoreThreads, prestartCoreThread, purge, remove, setCorePoolSize, setKeepAliveTime, setMaximumPoolSize, setRejectedExecutionHandler, setThreadFactory, shutdown, shutdownNow, terminated, toString

Methods inherited from class java.util.concurrent.AbstractExecutorService

invokeAll, invokeAll, invokeAny, invokeAny, newTaskFor, newTaskFor, submit, submit, submit

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.concurrent.ExecutorService

close

Constructor Details

AutoScaleThreadPool

public AutoScaleThreadPool(int corePoolSize,
 int maximumPoolSize,
 long keepAliveTime,
 TimeUnit unit,
 BlockingQueue<Runnable> workQueue,
 AutoScaleThreadPool.ScaleRule scaleRule)

调用父类的构造方法，并初始化HashMap和线程池名称

Parameters:

corePoolSize - 线程池核心线程数

maximumPoolSize - 线程池最大线程数

keepAliveTime - 线程的最大空闲时间

unit - 空闲时间的单位

workQueue - 保存被提交任务的队列

AutoScaleThreadPool

public AutoScaleThreadPool(int corePoolSize,
 int maximumPoolSize,
 long keepAliveTime,
 TimeUnit unit,
 BlockingQueue<Runnable> workQueue,
 ThreadFactory threadFactory,
 AutoScaleThreadPool.ScaleRule scaleRule)

调用父类的构造方法，并初始化HashMap和线程池名称

Parameters:

corePoolSize - 线程池核心线程数

maximumPoolSize - 线程池最大线程数

keepAliveTime - 线程的最大空闲时间

unit - 空闲时间的单位

workQueue - 保存被提交任务的队列

AutoScaleThreadPool

public AutoScaleThreadPool(int corePoolSize,
 int maximumPoolSize,
 long keepAliveTime,
 TimeUnit unit,
 BlockingQueue<Runnable> workQueue,
 RejectedExecutionHandler handler,
 AutoScaleThreadPool.ScaleRule scaleRule)

调用父类的构造方法，并初始化HashMap和线程池名称

Parameters:

corePoolSize - 线程池核心线程数

maximumPoolSize - 线程池最大线程数

keepAliveTime - 线程的最大空闲时间

unit - 空闲时间的单位

workQueue - 保存被提交任务的队列

AutoScaleThreadPool

public AutoScaleThreadPool(int corePoolSize,
 int maximumPoolSize,
 long keepAliveTime,
 TimeUnit unit,
 BlockingQueue<Runnable> workQueue,
 ThreadFactory threadFactory,
 RejectedExecutionHandler handler,
 AutoScaleThreadPool.ScaleRule scaleRule)

调用父类的构造方法，并初始化HashMap和线程池名称

Parameters:

corePoolSize - 线程池核心线程数

maximumPoolSize - 线程池最大线程数

keepAliveTime - 线程的最大空闲时间

unit - 空闲时间的单位

workQueue - 保存被提交任务的队列

threadFactory - 线程工厂

Method Details

beforeExecute

protected void beforeExecute(Thread t,
 Runnable r)

Overrides:

beforeExecute in class ThreadPoolExecutor

afterExecute

protected void afterExecute(Runnable r,
 Throwable t)

Overrides:

afterExecute in class ThreadPoolExecutor