org.apache.zookeeper.server

Class WorkerService

java.lang.Object

org.apache.zookeeper.server.WorkerService

public class WorkerService
extends Object

WorkerService is a worker thread pool for running tasks and is implemented using one or more ExecutorServices. A WorkerService can support assignable threads, which it does by creating N separate single thread ExecutorServices, or non-assignable threads, which it does by creating a single N-thread ExecutorService. - NIOServerCnxnFactory uses a non-assignable WorkerService because the socket IO requests are order independent and allowing the ExecutorService to handle thread assignment gives optimal performance. - CommitProcessor uses an assignable WorkerService because requests for a given session must be processed in order. ExecutorService provides queue management and thread restarting, so it's useful even with a single thread.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	WorkerService.WorkRequest Callers should implement a class extending WorkRequest in order to schedule work with the service.

Constructor Summary

Constructors

Constructor and Description
WorkerService(String name, int numThreads, boolean useAssignableThreads)

Method Summary

Modifier and Type	Method and Description
void	join(long shutdownTimeoutMS)
void	schedule(WorkerService.WorkRequest workRequest) Schedule work to be done.
void	schedule(WorkerService.WorkRequest workRequest, long id) Schedule work to be done by the thread assigned to this id.
void	start()
void	stop()

Methods inherited from class java.lang.Object

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

Constructor Detail

WorkerService

public WorkerService(String name,
                     int numThreads,
                     boolean useAssignableThreads)

Parameters:

name - worker threads are named Thread-##

numThreads - number of worker threads (0 - N) If 0, scheduled work is run immediately by the calling thread.

useAssignableThreads - whether the worker threads should be individually assignable or not

Method Detail

schedule

public void schedule(WorkerService.WorkRequest workRequest)

Schedule work to be done. If a worker thread pool is not being used, work is done directly by this thread. This schedule API is for use with non-assignable WorkerServices. For assignable WorkerServices, will always run on the first thread.

schedule

public void schedule(WorkerService.WorkRequest workRequest,
                     long id)

Schedule work to be done by the thread assigned to this id. Thread assignment is a single mod operation on the number of threads. If a worker thread pool is not being used, work is done directly by this thread.

start

public void start()

stop

public void stop()

join

public void join(long shutdownTimeoutMS)