net.floodlightcontroller.core.util
Class SingletonTask

java.lang.Object
  net.floodlightcontroller.core.util.SingletonTask

public class SingletonTask
extends java.lang.Object

This allows you to represent a task that should be queued for future execution but where you only want the task to complete once in response to some sequence of events. For example, if you get a change notification and want to reload state, you only want to reload the state once, at the end, and don't want to queue an update for every notification that might come in. The semantics are as follows: * If the task hasn't begun yet, do not queue a new task * If the task has begun, set a bit to restart it after the current task finishes

Nested Class Summary

protected static class	SingletonTask.SingletonTaskContext
protected static class	SingletonTask.SingletonTaskWorker

Field Summary

protected SingletonTask.SingletonTaskContext	context
protected static org.slf4j.Logger	logger
protected java.util.concurrent.ScheduledExecutorService	ses
protected java.lang.Runnable	task

Constructor Summary

SingletonTask(java.util.concurrent.ScheduledExecutorService ses, java.lang.Runnable task)
Construct a new SingletonTask for the given runnable.

Method Summary

void	reschedule(long delay, java.util.concurrent.TimeUnit unit) Schedule the task to run if there's not already a task scheduled If there is such a task waiting that has not already started, it cancel that task and reschedule it to run at the given time.

Methods inherited from class java.lang.Object

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

Field Detail

logger

protected static org.slf4j.Logger logger

context

protected SingletonTask.SingletonTaskContext context

task

protected java.lang.Runnable task

ses

protected java.util.concurrent.ScheduledExecutorService ses

Constructor Detail

SingletonTask

public SingletonTask(java.util.concurrent.ScheduledExecutorService ses,
                     java.lang.Runnable task)

Construct a new SingletonTask for the given runnable. The context is used to manage the state of the task execution and can be shared by more than one instance of the runnable.

Parameters:

context -

Task -

Method Detail

reschedule

public void reschedule(long delay,
                       java.util.concurrent.TimeUnit unit)

Schedule the task to run if there's not already a task scheduled If there is such a task waiting that has not already started, it cancel that task and reschedule it to run at the given time. If the task is already started, it will cause the task to be rescheduled once it completes to run after delay from the time of reschedule.

Parameters:

delay - the delay in scheduling

unit - the timeunit of the delay