org.jgroups.util
Interface TimeScheduler

All Known Implementing Classes:
DefaultTimeScheduler, HashedTimingWheel, MockTimeScheduler, TimeScheduler2, TimeScheduler3

public interface TimeScheduler

Timer-like interface which allows for execution of tasks. Taks can be executed

Author:
Bela Ban

Nested Class Summary
static interface TimeScheduler.Task
          The interface that dynamic tasks (scheduleWithDynamicInterval(org.jgroups.util.TimeScheduler.Task)) must implement
 
Method Summary
 java.lang.String dumpTimerTasks()
          Returns a list of tasks currently waiting for execution.
 void execute(java.lang.Runnable command)
          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
 boolean isShutdown()
          Returns true if stop() has been called, false otherwise
 java.util.concurrent.Future<?> schedule(java.lang.Runnable command, long 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 command, long initialDelay, long period, 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.
 java.util.concurrent.Future<?> scheduleWithDynamicInterval(TimeScheduler.Task task)
          Schedule a task for execution at varying intervals.
 java.util.concurrent.Future<?> scheduleWithFixedDelay(java.lang.Runnable command, long initialDelay, 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 factory)
           
 int size()
          Returns the number of tasks currently in the queue.
 void stop()
          Stops the scheduler if running, cancelling all pending tasks
 

Method Detail

execute

void execute(java.lang.Runnable command)
Executes command with zero required delay. This has effect equivalent to schedule(command, 0, anyUnit).

Parameters:
command - the task to execute
Throws:
java.util.concurrent.RejectedExecutionException - at discretion of RejectedExecutionHandler, if task cannot be accepted for execution because the executor has been shut down.
java.lang.NullPointerException - if command is null

schedule

java.util.concurrent.Future<?> schedule(java.lang.Runnable command,
                                        long delay,
                                        java.util.concurrent.TimeUnit unit)
Creates and executes a one-shot action that becomes enabled after the given delay.

Parameters:
command - the task to execute
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
Throws:
java.util.concurrent.RejectedExecutionException - if the task cannot be scheduled for execution
java.lang.NullPointerException - if command is null

scheduleWithFixedDelay

java.util.concurrent.Future<?> scheduleWithFixedDelay(java.lang.Runnable command,
                                                      long initialDelay,
                                                      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. 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.

Parameters:
command - the task to execute
initialDelay - 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
Throws:
java.util.concurrent.RejectedExecutionException - if the task cannot be scheduled for execution
java.lang.NullPointerException - if command is null
java.lang.IllegalArgumentException - if delay less than or equal to zero

scheduleAtFixedRate

java.util.concurrent.Future<?> scheduleAtFixedRate(java.lang.Runnable command,
                                                   long initialDelay,
                                                   long period,
                                                   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. 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.

Parameters:
command - the task to execute
initialDelay - the time to delay first execution
period - 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
Throws:
java.util.concurrent.RejectedExecutionException - if the task cannot be scheduled for execution
java.lang.NullPointerException - if command is null
java.lang.IllegalArgumentException - if period less than or equal to zero

scheduleWithDynamicInterval

java.util.concurrent.Future<?> scheduleWithDynamicInterval(TimeScheduler.Task task)
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() return a value <= 0 or the task is cancelled.

Parameters:
task - the task to execute

setThreadFactory

void setThreadFactory(ThreadFactory factory)

dumpTimerTasks

java.lang.String dumpTimerTasks()
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.

Returns:

getMinThreads

int getMinThreads()
Returns the configured core threads, or -1 if not applicable

Returns:

setMinThreads

void setMinThreads(int size)
Sets the core pool size. Can be ignored if not applicable


getMaxThreads

int getMaxThreads()
Returns the configured max threads, or -1 if not applicable

Returns:

setMaxThreads

void setMaxThreads(int size)
Sets the max pool size. Can be ignored if not applicable


getKeepAliveTime

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


setKeepAliveTime

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


getCurrentThreads

int getCurrentThreads()
Returns the current threads in the pool, or -1 if not applicable

Returns:

size

int size()
Returns the number of tasks currently in the queue.

Returns:
The number of tasks currently in the queue.

stop

void stop()
Stops the scheduler if running, cancelling all pending tasks


isShutdown

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



Copyright © 1998-2012 Bela Ban / Red Hat. All Rights Reserved.