org.apache.ambari.server.controller.utilities

Class ScalingThreadPoolExecutor

java.lang.Object

java.util.concurrent.AbstractExecutorService

java.util.concurrent.ThreadPoolExecutor

org.apache.ambari.server.controller.utilities.ScalingThreadPoolExecutor

All Implemented Interfaces:

Executor, ExecutorService

public class ScalingThreadPoolExecutor
extends ThreadPoolExecutor

An ExecutorService that executes each submitted task using one of possibly several pooled threads. It also scales up the number of threads in the pool if the number of submissions exceeds the core size of the pool. The pool can scale up to the specified maximum pool size. If the number of submissions exceeds the sum of the core and maximum size of the thread pool, the submissions are then handled by the provided RejectedExecutionHandler. If the overflowing submissions need to be handled, BufferedThreadPoolExecutorCompletionService can be used to buffer up overflowing submissions for later submission as threads become available.

See Also:

BufferedThreadPoolExecutorCompletionService

Nested Class Summary

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

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

Constructor Summary

Constructors

Constructor and Description
ScalingThreadPoolExecutor(int corePoolSize, int maximumPoolSize, long keepAliveTime, TimeUnit unit, int workerQueueSize) Constructor.

Method Summary

Methods inherited from class java.util.concurrent.ThreadPoolExecutor

afterExecute, allowCoreThreadTimeOut, allowsCoreThreadTimeOut, awaitTermination, beforeExecute, 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

Constructor Detail

ScalingThreadPoolExecutor

public ScalingThreadPoolExecutor(int corePoolSize,
                                 int maximumPoolSize,
                                 long keepAliveTime,
                                 TimeUnit unit,
                                 int workerQueueSize)

Constructor.

Parameters:

corePoolSize - the number of threads which will be considered as "core". If core thread timeout is not enabled, then this will be the minimum number of threads, always. With core timeout enabled, then this will be the number of threads spun up to handle incoming work regardless of worker queue size.

maximumPoolSize - the maximum number of threads which can be spawned when an ExecutorService encounters a failure inserting into the work queue. These threads are not spawned to handle entries into the work queue; they are only spawned if the queue fills and a RejectedExecutionHandler is invoked.

keepAliveTime - the TTL for core threads

unit - the time unit for core threads

workerQueueSize - the size of the worker queue. The threads specified by ThreadPoolExecutor.getMaximumPoolSize() will only be created if the worker queue is exhausted.