org.jgroups.util
Class TimeScheduler3

java.lang.Object
  org.jgroups.util.TimeScheduler3

All Implemented Interfaces:

java.lang.Runnable, TimeScheduler

public class TimeScheduler3
extends java.lang.Object
implements TimeScheduler, java.lang.Runnable

Implementation of TimeScheduler. Based on the TimeScheduler2 implementation with various fixes and enhancements. Uses a DelayQueue to order tasks according to execution times

Since:

3.3

Author:

Bela Ban

Nested Class Summary

protected class	TimeScheduler3.RecurringTask Tasks which runs more than once, either dynamic, fixed-rate or fixed-delay, until cancelled
protected static class	TimeScheduler3.Task
protected static class	TimeScheduler3.TaskType

Field Summary

protected static Log	log
protected java.util.concurrent.ThreadPoolExecutor	pool Thread pool used to execute the tasks
protected java.util.concurrent.BlockingQueue<TimeScheduler3.Task>	queue DelayQueue with tasks being sorted according to execution times (next execution first)
protected java.lang.Thread	runner Thread which removes tasks ready to be executed from the queue and submits them to the pool for execution
protected boolean	running
protected ThreadFactory	timer_thread_factory

Constructor Summary

TimeScheduler3()
Create a scheduler that executes tasks in dynamically adjustable intervals

TimeScheduler3(ThreadFactory factory, int min_threads, int max_threads, long keep_alive_time, int max_queue_size, java.lang.String rejection_policy)

Method Summary

protected TimeScheduler3.Task	add(TimeScheduler3.Task task)
protected java.util.concurrent.Future<?>	doSchedule(TimeScheduler3.Task task, long initial_delay)
java.lang.String	dumpTimerTasks() Returns a list of tasks currently waiting for execution.
void	execute(java.lang.Runnable task) Executes command with zero required delay.
int	getCurrentThreads() Returns the current threads in the pool, or -1 if not applicable
long	getKeepAliveTime() Returns the keep alive time (in ms) of the thread pool, or -1 if not applicable
int	getMaxThreads() Returns the configured max threads, or -1 if not applicable
int	getMinThreads() Returns the configured core threads, or -1 if not applicable
int	getQueueSize()
boolean	isShutdown() Returns true if stop() has been called, false otherwise
void	run()
java.util.concurrent.Future<?>	schedule(java.lang.Runnable work, long initial_delay, java.util.concurrent.TimeUnit unit) Creates and executes a one-shot action that becomes enabled after the given delay.
java.util.concurrent.Future<?>	scheduleAtFixedRate(java.lang.Runnable work, long initial_delay, long delay, java.util.concurrent.TimeUnit unit) Creates and executes a periodic action that becomes enabled first after the given initial delay, and subsequently with the given period; that is executions will commence after initialDelay then initialDelay+period, then initialDelay + 2 * period, and so on.
protected java.util.concurrent.Future<?>	scheduleRecurring(java.lang.Runnable work, TimeScheduler3.TaskType type, long initial_delay, long delay, java.util.concurrent.TimeUnit unit)
java.util.concurrent.Future<?>	scheduleWithDynamicInterval(TimeScheduler.Task work) Schedule a task for execution at varying intervals.
java.util.concurrent.Future<?>	scheduleWithFixedDelay(java.lang.Runnable work, long initial_delay, long delay, java.util.concurrent.TimeUnit unit) Creates and executes a periodic action that becomes enabled first after the given initial delay, and subsequently with the given delay between the termination of one execution and the commencement of the next.
void	setKeepAliveTime(long time) Sets the keep alive time (in ms) of the thread pool.
void	setMaxThreads(int size) Sets the max pool size.
void	setMinThreads(int size) Sets the core pool size.
void	setThreadFactory(ThreadFactory f)
int	size() Returns the number of tasks currently in the queue.
protected void	start()
protected void	startRunner()
void	stop() Stops the timer, cancelling all tasks
protected void	stopRunner()
protected void	submitToPool(TimeScheduler3.Task entry)
java.lang.String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

pool

protected final java.util.concurrent.ThreadPoolExecutor pool

Thread pool used to execute the tasks

queue

protected final java.util.concurrent.BlockingQueue<TimeScheduler3.Task> queue

DelayQueue with tasks being sorted according to execution times (next execution first)

runner

protected java.lang.Thread runner

Thread which removes tasks ready to be executed from the queue and submits them to the pool for execution

running

protected volatile boolean running

log

protected static final Log log

timer_thread_factory

protected ThreadFactory timer_thread_factory

Constructor Detail

TimeScheduler3

public TimeScheduler3()

Create a scheduler that executes tasks in dynamically adjustable intervals

TimeScheduler3

public TimeScheduler3(ThreadFactory factory,
                      int min_threads,
                      int max_threads,
                      long keep_alive_time,
                      int max_queue_size,
                      java.lang.String rejection_policy)

Method Detail

setThreadFactory

public void setThreadFactory(ThreadFactory f)

Specified by:

setThreadFactory in interface TimeScheduler

getMinThreads

public int getMinThreads()

Description copied from interface: TimeScheduler

Returns the configured core threads, or -1 if not applicable

Specified by:

getMinThreads in interface TimeScheduler

Returns:

setMinThreads

public void setMinThreads(int size)

Description copied from interface: TimeScheduler

Sets the core pool size. Can be ignored if not applicable

Specified by:

setMinThreads in interface TimeScheduler

getMaxThreads

public int getMaxThreads()

Description copied from interface: TimeScheduler

Returns the configured max threads, or -1 if not applicable

Specified by:

getMaxThreads in interface TimeScheduler

Returns:

setMaxThreads

public void setMaxThreads(int size)

Description copied from interface: TimeScheduler

Sets the max pool size. Can be ignored if not applicable

Specified by:

setMaxThreads in interface TimeScheduler

getKeepAliveTime

public long getKeepAliveTime()

Description copied from interface: TimeScheduler

Returns the keep alive time (in ms) of the thread pool, or -1 if not applicable

Specified by:

getKeepAliveTime in interface TimeScheduler

setKeepAliveTime

public void setKeepAliveTime(long time)

Description copied from interface: TimeScheduler

Sets the keep alive time (in ms) of the thread pool. Can be ignored if not applicable

Specified by:

setKeepAliveTime in interface TimeScheduler

getCurrentThreads

public int getCurrentThreads()

Description copied from interface: TimeScheduler

Returns the current threads in the pool, or -1 if not applicable

Specified by:

getCurrentThreads in interface TimeScheduler

Returns:

getQueueSize

public int getQueueSize()

size

public int size()

Description copied from interface: TimeScheduler

Returns the number of tasks currently in the queue.

Specified by:

size in interface TimeScheduler

Returns:

The number of tasks currently in the queue.

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

isShutdown

public boolean isShutdown()

Description copied from interface: TimeScheduler

Returns true if stop() has been called, false otherwise

Specified by:

isShutdown in interface TimeScheduler

dumpTimerTasks

public java.lang.String dumpTimerTasks()

Description copied from interface: TimeScheduler

Returns a list of tasks currently waiting for execution. If there are a lot of tasks, the returned string should probably only return the number of tasks rather than a full dump.

Specified by:

dumpTimerTasks in interface TimeScheduler

Returns:

execute

public void execute(java.lang.Runnable task)

Description copied from interface: TimeScheduler

Executes command with zero required delay. This has effect equivalent to schedule(command, 0, anyUnit).

Specified by:

execute in interface TimeScheduler

Parameters:

task - the task to execute

schedule

public java.util.concurrent.Future<?> schedule(java.lang.Runnable work,
                                               long initial_delay,
                                               java.util.concurrent.TimeUnit unit)

Description copied from interface: TimeScheduler

Creates and executes a one-shot action that becomes enabled after the given delay.

Specified by:

schedule in interface TimeScheduler

Parameters:

work - the task to execute

initial_delay - the time from now to delay execution

unit - the time unit of the delay parameter

Returns:

a ScheduledFuture representing pending completion of the task and whose get() method will return null upon completion

scheduleWithFixedDelay

public java.util.concurrent.Future<?> scheduleWithFixedDelay(java.lang.Runnable work,
                                                             long initial_delay,
                                                             long delay,
                                                             java.util.concurrent.TimeUnit unit)

Description copied from interface: TimeScheduler

Creates and executes a periodic action that becomes enabled first after the given initial delay, and subsequently with the given delay between the termination of one execution and the commencement of the next. If any execution of the task encounters an exception, subsequent executions are suppressed. Otherwise, the task will only terminate via cancellation or termination of the executor.

Specified by:

scheduleWithFixedDelay in interface TimeScheduler

Parameters:

work - the task to execute

initial_delay - the time to delay first execution

delay - the delay between the termination of one execution and the commencement of the next

unit - the time unit of the initialDelay and delay parameters

Returns:

a ScheduledFuture representing pending completion of the task, and whose get() method will throw an exception upon cancellation

scheduleAtFixedRate

public java.util.concurrent.Future<?> scheduleAtFixedRate(java.lang.Runnable work,
                                                          long initial_delay,
                                                          long delay,
                                                          java.util.concurrent.TimeUnit unit)

Description copied from interface: TimeScheduler

Creates and executes a periodic action that becomes enabled first after the given initial delay, and subsequently with the given period; that is executions will commence after initialDelay then initialDelay+period, then initialDelay + 2 * period, and so on. If any execution of the task encounters an exception, subsequent executions are suppressed. Otherwise, the task will only terminate via cancellation or termination of the executor. If any execution of this task takes longer than its period, then subsequent executions may start late, but will not concurrently execute.

Specified by:

scheduleAtFixedRate in interface TimeScheduler

Parameters:

work - the task to execute

initial_delay - the time to delay first execution

delay - the period between successive executions

unit - the time unit of the initialDelay and period parameters

Returns:

a ScheduledFuture representing pending completion of the task, and whose get() method will throw an exception upon cancellation

scheduleWithDynamicInterval

public java.util.concurrent.Future<?> scheduleWithDynamicInterval(TimeScheduler.Task work)

Schedule a task for execution at varying intervals. After execution, the task will get rescheduled after TimeScheduler.Task.nextInterval() milliseconds. The task is never done until nextInterval() returns a value <= 0 or the task is cancelled.

Note that the task is rescheduled relative to the last time is actually executed. This is similar to scheduleWithFixedDelay(Runnable,long,long,java.util.concurrent.TimeUnit).

Specified by:

scheduleWithDynamicInterval in interface TimeScheduler

Parameters:

work - the task to execute

start

protected void start()

stop

public void stop()

Stops the timer, cancelling all tasks

Specified by:

stop in interface TimeScheduler

run

public void run()

Specified by:

run in interface java.lang.Runnable

scheduleRecurring

protected java.util.concurrent.Future<?> scheduleRecurring(java.lang.Runnable work,
                                                           TimeScheduler3.TaskType type,
                                                           long initial_delay,
                                                           long delay,
                                                           java.util.concurrent.TimeUnit unit)

doSchedule

protected java.util.concurrent.Future<?> doSchedule(TimeScheduler3.Task task,
                                                    long initial_delay)

submitToPool

protected void submitToPool(TimeScheduler3.Task entry)

add

protected TimeScheduler3.Task add(TimeScheduler3.Task task)

startRunner

protected void startRunner()

stopRunner

protected void stopRunner()