Package org.jgroups.util

Interface TimeScheduler

All Superinterfaces:
ThreadManager
All Known Implementing Classes:
DefaultTimeScheduler, HashedTimingWheel, TimeScheduler2
public interface TimeScheduler extends ThreadManager
Timer-like interface which allows for execution of tasks. Taks can be executed
  • one time only
  • at recurring time intervals. Intervals can be fixed-delay or fixed-rate, see ScheduledExecutorService for details
  • dynamic; at the end of the task execution, a task is asked what the next execution time should be. To do this, method TimeScheduler.Task.nextInterval() needs to be implemented.
Author:
Bela Ban

  • Method Details

    • execute

      void execute(Runnable command)
      Executes command with zero required delay. This has effect equivalent to schedule(command, 0, anyUnit).
      Parameters:
      command - the task to execute
      Throws:
      RejectedExecutionException - at discretion of RejectedExecutionHandler, if task cannot be accepted for execution because the executor has been shut down.
      NullPointerException - if command is null

    • schedule

      Future<?> schedule(Runnable command, long delay, 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:
      RejectedExecutionException - if the task cannot be scheduled for execution
      NullPointerException - if command is null

    • scheduleWithFixedDelay

      Future<?> scheduleWithFixedDelay(Runnable command, long initialDelay, long delay, 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:
      RejectedExecutionException - if the task cannot be scheduled for execution
      NullPointerException - if command is null
      IllegalArgumentException - if delay less than or equal to zero

    • scheduleAtFixedRate

      Future<?> scheduleAtFixedRate(Runnable command, long initialDelay, long period, 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:
      RejectedExecutionException - if the task cannot be scheduled for execution
      NullPointerException - if command is null
      IllegalArgumentException - if period less than or equal to zero

    • scheduleWithDynamicInterval

      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 invalid input: '<'= 0 or the task is cancelled.
      Parameters:
      task - the task to execute

    • setThreadFactory

      void setThreadFactory(ThreadFactory factory)

    • dumpTimerTasks

      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