Klasse QueueingThreadPoolExecutor

java.lang.Object

java.util.concurrent.AbstractExecutorService

java.util.concurrent.ThreadPoolExecutor

org.jupnp.QueueingThreadPoolExecutor

Alle implementierten Schnittstellen:

Executor, ExecutorService

public class QueueingThreadPoolExecutor
extends ThreadPoolExecutor

This is a thread pool executor service, which works as a developer would expect it to work. The default ThreadPoolExecutor does the following (see the official JavaDoc):

• If fewer than corePoolSize threads are running, the Executor always prefers adding a new thread rather than queuing.
• If corePoolSize or more threads are running, the Executor always prefers queuing a request rather than adding a new thread.
• If a request cannot be queued, a new thread is created unless this would exceed maximumPoolSize, in which case, the task will be rejected.

This class in contrast implements the following logic:

• corePoolSize is 1, so threads are only created on demand
• If the number of busy threads is smaller than the threadPoolSize, the Executor always prefers adding (or reusing) a thread rather than queuing it.
• If threadPoolSize threads are busy, new requests will be put in a FIFO queue and processed as soon as a thread becomes idle.
• The queue size is unbound, i.e. requests will never be rejected.
• Threads are terminated after being idle for at least 10 seconds.

Please note that this implementation (with its partially hard-coded settings) is specifically targeted for use on embedded devices without a high throughput. If you intend to use it for mass data processing on a server, you should definitely tweak those settings.

Autor:

Kai Kreuzer - Initial contribution and API

Verschachtelte Klassen - Übersicht

Von Klasse geerbte verschachtelte Klassen/Schnittstellen java.util.concurrent.ThreadPoolExecutor

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

Konstruktorübersicht

Konstruktoren

Modifizierer	Konstruktor	Beschreibung
protected	QueueingThreadPoolExecutor(String name, int threadPoolSize)	Allows to subclass QueueingThreadPoolExecutor.

Methodenübersicht

Modifizierer und Typ	Methode	Beschreibung
protected void	addToQueue(Runnable runnable)	Adds a new task to the queue
protected void	afterExecute(Runnable r, Throwable t)
static QueueingThreadPoolExecutor	createInstance(String name, int threadPoolSize)	Creates a new instance of QueueingThreadPoolExecutor
static QueueingThreadPoolExecutor	createInstance(String name, int threadPoolSize, BlockingQueue<Runnable> taskQueue)	Creates a new instance of QueueingThreadPoolExecutor
void	execute(Runnable command)
BlockingQueue<Runnable>	getQueue()
void	setRejectedExecutionHandler(RejectedExecutionHandler handler)	This implementation does not allow setting a custom handler.

Von Klasse geerbte Methoden java.util.concurrent.ThreadPoolExecutor

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

Von Klasse geerbte Methoden java.util.concurrent.AbstractExecutorService

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

Von Klasse geerbte Methoden java.lang.Object

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

Konstruktordetails

QueueingThreadPoolExecutor

protected QueueingThreadPoolExecutor(String name,
 int threadPoolSize)

Allows to subclass QueueingThreadPoolExecutor.

Methodendetails

createInstance

public static QueueingThreadPoolExecutor createInstance(String name,
 int threadPoolSize)

Creates a new instance of QueueingThreadPoolExecutor

Parameter:

name - the name of the thread pool, will be used as a prefix for the name of the threads

threadPoolSize - the maximum size of the pool

Gibt zurück:

the QueueingThreadPoolExecutor instance

createInstance

public static QueueingThreadPoolExecutor createInstance(String name,
 int threadPoolSize,
 BlockingQueue<Runnable> taskQueue)

Creates a new instance of QueueingThreadPoolExecutor

Parameter:

name - the name of the thread pool, will be used as a prefix for the name of the threads

threadPoolSize - the maximum size of the pool

taskQueue - the task queue to use

Gibt zurück:

the QueueingThreadPoolExecutor instance

addToQueue

protected void addToQueue(Runnable runnable)

Adds a new task to the queue

Parameter:

runnable - the task to add

afterExecute

protected void afterExecute(Runnable r,
 Throwable t)

Setzt außer Kraft:

afterExecute in Klasse ThreadPoolExecutor

setRejectedExecutionHandler

public void setRejectedExecutionHandler(RejectedExecutionHandler handler)

This implementation does not allow setting a custom handler.

Setzt außer Kraft:

setRejectedExecutionHandler in Klasse ThreadPoolExecutor

Löst aus:

UnsupportedOperationException - if called.

getQueue

public BlockingQueue<Runnable> getQueue()

Setzt außer Kraft:

getQueue in Klasse ThreadPoolExecutor

execute

public void execute(Runnable command)

Angegeben von:

execute in Schnittstelle Executor

Setzt außer Kraft:

execute in Klasse ThreadPoolExecutor