Package org.apache.solr.common.util

Class ExecutorUtil

java.lang.Object

org.apache.solr.common.util.ExecutorUtil

public class ExecutorUtil
extends Object

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static interface	ExecutorUtil.InheritableThreadLocalProvider	Any class which wants to carry forward the thread local values to the threads run by thread pools must implement this interface and the implementation should be registered here
static class	ExecutorUtil.MDCAwareThreadPoolExecutor

Constructor Summary

Constructors

Constructor	Description
ExecutorUtil()

Method Summary

Modifier and Type	Method	Description
static void	addThreadLocalProvider(ExecutorUtil.InheritableThreadLocalProvider provider)
static void	awaitTermination(ExecutorService pool)	Await the termination of an ExecutorService for a default of 60 seconds, then force shutdown the remaining threads and wait another 60 seconds.
static void	awaitTerminationForever(ExecutorService pool)	Await the termination of an ExecutorService until all threads are complete, or until we are interrupted, at which point the ExecutorService will be interrupted as well.
static boolean	isShutdown(ExecutorService pool)
static boolean	isSolrServerThread()
static boolean	isTerminated(ExecutorService pool)
static ExecutorService	newMDCAwareCachedThreadPool(int maxThreads, int queueCapacity, ThreadFactory threadFactory)	Create a new pool of threads.
static ExecutorService	newMDCAwareCachedThreadPool(String name)	Create a cached thread pool using a named thread factory
static ExecutorService	newMDCAwareCachedThreadPool(ThreadFactory threadFactory)	Create a new pool of threads, with no limit for the number of threads.
static ExecutorService	newMDCAwareFixedThreadPool(int nThreads, ThreadFactory threadFactory)	See Executors.newFixedThreadPool(int, ThreadFactory)
static ExecutorService	newMDCAwareSingleLazyThreadExecutor(ThreadFactory threadFactory, long keepAliveTime, TimeUnit unit)	Similar to newMDCAwareSingleThreadExecutor(ThreadFactory), but the thread will not be kept active after the specified time if no task is submitted to the executor.
static ExecutorService	newMDCAwareSingleThreadExecutor(ThreadFactory threadFactory)	See Executors.newSingleThreadExecutor(ThreadFactory).
static void	resetThreadLocalProviders()	Resets everything added via addThreadLocalProvider(InheritableThreadLocalProvider).
static void	setServerThreadFlag(Boolean flag)
static void	shutdownAndAwaitTermination(ExecutorService pool)	Shutdown the ExecutorService and wait for 60 seconds for the threads to complete.
static void	shutdownAndAwaitTerminationForever(ExecutorService pool)	Shutdown the ExecutorService and wait forever for the threads to complete.
static void	shutdownNowAndAwaitTermination(ExecutorService pool)
static <T> Collection<T>	submitAllAndAwaitAggregatingExceptions(ExecutorService service, List<? extends Callable<T>> tasks)	Takes an executor and a list of Callables and executes them returning the results as a list.

Methods inherited from class java.lang.Object

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

Constructor Detail

ExecutorUtil

public ExecutorUtil()

Method Detail

resetThreadLocalProviders

public static void resetThreadLocalProviders()

Resets everything added via addThreadLocalProvider(InheritableThreadLocalProvider). Useful to call at the beginning of tests.

addThreadLocalProvider

public static void addThreadLocalProvider(ExecutorUtil.InheritableThreadLocalProvider provider)

isShutdown

public static boolean isShutdown(ExecutorService pool)

isTerminated

public static boolean isTerminated(ExecutorService pool)

shutdownAndAwaitTermination

public static void shutdownAndAwaitTermination(ExecutorService pool)

Shutdown the ExecutorService and wait for 60 seconds for the threads to complete. More detail on the waiting can be found in awaitTermination(ExecutorService).

Parameters:

pool - The ExecutorService to shut down and wait on

shutdownAndAwaitTerminationForever

public static void shutdownAndAwaitTerminationForever(ExecutorService pool)

Shutdown the ExecutorService and wait forever for the threads to complete. More detail on the waiting can be found in awaitTerminationForever(ExecutorService).

This should likely not be used in close() methods, as we want to time bound when shutting down. However, sometimes ExecutorServices are used to submit a list of tasks and awaiting termination is akin to waiting on the list of Futures to complete. In that case, this method should be used as there is no inherent time bound to waiting on those tasks to complete.

Parameters:

pool - The ExecutorService to shut down and wait on

shutdownNowAndAwaitTermination

public static void shutdownNowAndAwaitTermination(ExecutorService pool)

awaitTermination

public static void awaitTermination(ExecutorService pool)

Await the termination of an ExecutorService for a default of 60 seconds, then force shutdown the remaining threads and wait another 60 seconds.

Parameters:

pool - the ExecutorService to wait on

awaitTerminationForever

public static void awaitTerminationForever(ExecutorService pool)

Await the termination of an ExecutorService until all threads are complete, or until we are interrupted, at which point the ExecutorService will be interrupted as well.

Parameters:

pool - the ExecutorService to wait on

newMDCAwareFixedThreadPool

public static ExecutorService newMDCAwareFixedThreadPool(int nThreads,
                                                         ThreadFactory threadFactory)

See Executors.newFixedThreadPool(int, ThreadFactory)

newMDCAwareSingleThreadExecutor

public static ExecutorService newMDCAwareSingleThreadExecutor(ThreadFactory threadFactory)

See Executors.newSingleThreadExecutor(ThreadFactory). Note the thread is always active, even if no tasks are submitted to the executor.

newMDCAwareSingleLazyThreadExecutor

public static ExecutorService newMDCAwareSingleLazyThreadExecutor(ThreadFactory threadFactory,
                                                                  long keepAliveTime,
                                                                  TimeUnit unit)

Similar to newMDCAwareSingleThreadExecutor(ThreadFactory), but the thread will not be kept active after the specified time if no task is submitted to the executor.

newMDCAwareCachedThreadPool

public static ExecutorService newMDCAwareCachedThreadPool(String name)

Create a cached thread pool using a named thread factory

newMDCAwareCachedThreadPool

public static ExecutorService newMDCAwareCachedThreadPool(ThreadFactory threadFactory)

Create a new pool of threads, with no limit for the number of threads. The pool has no task queue. Each submitted task is executed immediately, either by reusing an existing thread if one is available, or by starting a new thread. Unused threads will be closed after 60 seconds.

newMDCAwareCachedThreadPool

public static ExecutorService newMDCAwareCachedThreadPool(int maxThreads,
                                                          int queueCapacity,
                                                          ThreadFactory threadFactory)

Create a new pool of threads. Threads are created for new work if there is room to do so up to maxThreads. Beyond that, the queue is used up to queueCapacity. Beyond that, work is rejected with an exception. Unused threads will be closed after 60 seconds.

isSolrServerThread

public static boolean isSolrServerThread()

setServerThreadFlag

public static void setServerThreadFlag(Boolean flag)

submitAllAndAwaitAggregatingExceptions

public static <T> Collection<T> submitAllAndAwaitAggregatingExceptions(ExecutorService service,
                                                                       List<? extends Callable<T>> tasks)
                                                                throws IOException

Takes an executor and a list of Callables and executes them returning the results as a list. The method waits for the return of every task even if one of them throws an exception. If any exception happens it will be thrown, wrapped into an IOException, and other following exceptions will be added as `addSuppressed` to the original exception

Type Parameters:

T - the response type

Parameters:

service - executor

tasks - the list of callables to be executed

Returns:

results list

Throws:

IOException - in case any exceptions happened