Package com.tangosol.util

Class TaskDaemon

java.lang.Object
com.tangosol.util.Base
com.tangosol.util.Daemon
com.tangosol.util.TaskDaemon
All Implemented Interfaces:
Guardable, Runnable
public class TaskDaemon extends Daemon
A Daemon thread handler that asynchronously executes Runnable tasks, either at a scheduled time or "as soon as possible".
Author:
cp 2003.10.09, cp 2006.02.23 (Coherence 3.2) bulletproofing for use in the CQC

  • Constructor Details

    • TaskDaemon

      public TaskDaemon()
      Default constructor. Creates a TaskDaemon using default settings. The daemon will not be automatically started.

    • TaskDaemon

      public TaskDaemon(String sName)
      Creates a TaskDaemon with the specified name. The daemon will not be automatically started.
      Parameters:
      sName - the thread name (may be null)

    • TaskDaemon

      public TaskDaemon(String sName, int nPriority, boolean fStart)
      Creates a TaskDaemon with a specified name and priority.
      Parameters:
      sName - the thread name (may be null)
      nPriority - the thread priority, between Thread.MIN_PRIORITY and Thread.MAX_PRIORITY inclusive
      fStart - pass true to start the thread immediately

    • TaskDaemon

      public TaskDaemon(String sName, int nPriority, boolean fStart, boolean fFinish, int cMillisTimeout)
      Creates a TaskDaemon with a specified name and priority.
      Parameters:
      sName - the thread name (may be null)
      nPriority - the thread priority, between Thread.MIN_PRIORITY and Thread.MAX_PRIORITY inclusive
      fStart - pass true to start the thread immediately
      fFinish - pass true to makes sure ripe tasks are run before the daemon shuts down
      cMillisTimeout - the number of milliseconds to wait after the previous task finished for a new task to be submitted before automatically shutting down the daemon thread

  • Method Details

    • run

      public void run()
      The task processing loop.
      Specified by:
      run in interface Runnable
      Specified by:
      run in class Daemon

    • stop

      public void stop(boolean fFinish)
      Request the daemon to stop, optionally completing tasks that have already been scheduled and are ready to be run.
      Parameters:
      fFinish - pass true if the daemon should finish any tasks that have already been scheduled before stopping

    • isFinishing

      public boolean isFinishing()
      Determine if the daemon will finish those scheduled tasks that are ripe (presently due to be run) before stopping.
      Returns:
      true if the daemon is configured to finish any ripe scheduled tasks before stopping

    • setFinishing

      public void setFinishing(boolean fFinish)
      Specify whether the daemon will finish scheduled tasks before stopping.
      Parameters:
      fFinish - pass true to force the daemon to finish any scheduled tasks before stopping

    • getIdleTimeout

      public long getIdleTimeout()
      Determine the length of time that the daemon will live without any activity before it stops itself.
      Returns:
      the timeout for the TaskDaemon's thread to live before being shut down

    • setIdleTimeout

      public void setIdleTimeout(long cMillis)
      Configure the daemon's timeout. Note that if the daemon shuts itself down, it will automatically restart when something is added to the queue.
      Parameters:
      cMillis - if greater than zero, the number of milliseconds that the daemon will wait with nothing in the queue before shutting itself down

    • executeTask

      public void executeTask(Runnable task)
      Schedule a task to be run by the daemon "as soon as possible".
      Parameters:
      task - a Runnable object to invoke

    • scheduleTask

      public void scheduleTask(Runnable task, long ldt)
      Schedule a task to be run at the specified time, or as soon after as possible.
      Parameters:
      task - a Runnable object to invoke
      ldt - a datetime value at which to run the task

    • executePeriodicTask

      public void executePeriodicTask(Runnable task, long cMillisInterval)
      Schedule a periodic task to be run "as soon as possible", and to repeat at the specified interval.
      Parameters:
      task - a Runnable object to invoke
      cMillisInterval - the number of milliseconds to wait after the task is run before running it again

    • schedulePeriodicTask

      public void schedulePeriodicTask(Runnable task, long ldtFirst, long cMillisInterval)
      Schedule a periodic task to be run at the specified time, and to repeat at the specified interval.
      Parameters:
      task - a Runnable object to invoke
      ldtFirst - a datetime value at which to first run the task
      cMillisInterval - the number of milliseconds to wait after the task is run before running it again

    • getTasks

      protected LongArray getTasks()
      Obtain the pending tasks.
      Returns:
      a LongArray keyed by SafeTimeMillis with a corresponding value being a List of tasks scheduled at that time

    • takeNextRipeTask

      protected Runnable takeNextRipeTask() throws InterruptedException
      Wait for the next scheduled task is ripe (due or overdue), then remove it from the pending schedule and return it.
      Returns:
      a task that is ripe to be run, or null if the TaskDaemon is shutting down and no task should be run
      Throws:
      InterruptedException - if this thread is interrupted while waiting for the next task

    • run

      protected void run(Runnable task)
      Execute a Runnable task.
      Parameters:
      task - a Runnable object

    • getMostRecentTaskTime

      protected long getMostRecentTaskTime()
      Determine when the most recent task was run.
      Returns:
      the date/time at which the most recent task was run

    • updateMostRecentTaskTime

      protected void updateMostRecentTaskTime()
      Set the time that the most recent task was run to the current time.

    • instantiatePeriodicTask

      protected Runnable instantiatePeriodicTask(Runnable task, long cMillisInterval)
      Create a task that will automatically be run on a periodic basis.
      Parameters:
      task - the actual task to run
      cMillisInterval - the period of time, in milliseconds, to wait between runs of the task
      Returns:
      a task that will run itself periodically

    • toString

      public String toString()
      Return a human-readable String representation of the Daemon.
      Overrides:
      toString in class Daemon
      Returns:
      a String describing the Daemon

    • getDescription

      protected String getDescription()
      Format the Daemon attributes into a String for inclusion in the String returned from the Daemon.toString() method.
      Overrides:
      getDescription in class Daemon
      Returns:
      a String listing the attributes of the Daemon

    • onException

      protected void onException(Throwable e, Runnable task)
      Process an exception that is thrown during a task execution. The default implementation logs the exception and continues.
      Parameters:
      e - Throwable object (a RuntimeException or an Error)
      task - the task that caused the exception