org.javades.jqueues.r5.entity.jq.queue.preemptive

Class AbstractPreemptiveSimQueue<J extends SimJob,Q extends AbstractPreemptiveSimQueue>

java.lang.Object

org.javades.jqueues.r5.entity.AbstractSimEntity

org.javades.jqueues.r5.entity.jq.AbstractSimJQ<J,Q>

org.javades.jqueues.r5.entity.jq.queue.AbstractSimQueue<J,Q>

org.javades.jqueues.r5.entity.jq.queue.AbstractClassicSimQueue<J,Q>

org.javades.jqueues.r5.entity.jq.queue.preemptive.AbstractPreemptiveSimQueue<J,Q>

Type Parameters:

J - The type of SimJobs supported.

Q - The type of SimQueues supported.

All Implemented Interfaces:

SimQueue<J,Q>, SimQoS<J,Q>, SimEntity, org.javades.jsimulation.r5.SimEventListResetListener

Direct Known Subclasses:

AbstractPreemptiveSimQueueQoS, P_LCFS, SRTF

public abstract class AbstractPreemptiveSimQueue<J extends SimJob,Q extends AbstractPreemptiveSimQueue>
extends AbstractClassicSimQueue<J,Q>

An abstract base class for preemptive queueing disciplines.

Implementations allow (through inheritance) the job requested service time to be (positive) infinite. Jobs with that feature will never depart through internal scheduling (can only depart due to preemption and the proper preemption strategy), even if time itself is positive or negative infinity. If time is infinite, jobs with finite service time requirement will always start and depart immediately upon arrival.

Author:

Jan de Jongh, TNO

Copyright (C) 2005-2017 Jan de Jongh, TNO

This file is covered by the LICENSE file in the root of this project.

Nested Class Summary

Nested classes/interfaces inherited from class org.javades.jqueues.r5.entity.AbstractSimEntity

AbstractSimEntity.Notifier, AbstractSimEntity.PreNotificationHook

Nested classes/interfaces inherited from interface org.javades.jqueues.r5.entity.jq.queue.SimQueue

SimQueue.AutoRevocationPolicy

Nested classes/interfaces inherited from interface org.javades.jqueues.r5.entity.SimEntity

SimEntity.Action, SimEntity.UnknownNotificationTypePolicy, SimEntity.UnknownOperationPolicy

Field Summary

Fields

Modifier and Type	Field and Description
static PreemptionStrategy	DEFAULT_PREEMPTION_STRATEGY The default preemption strategy, if none was specified upon construction.
protected Map<J,Double>	jobsBeingServed The jobs currently being served by a server, mapped onto the start time of this service chunk.
protected HashMapWithPreImageAndOrderedValueSet<J,Double>	remainingServiceTime The mapping from jobs in AbstractSimQueue.getJobsInServiceArea() to their respective remaining service times.
static double	TOLERANCE_RST The tolerance for rounding errors in the remaining service time.

Fields inherited from class org.javades.jqueues.r5.entity.jq.queue.AbstractSimQueue

eventsScheduled, SANITY

Fields inherited from class org.javades.jqueues.r5.entity.AbstractSimEntity

USE_ARRAY_OPTIMIZATION

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	AbstractPreemptiveSimQueue(org.javades.jsimulation.r5.SimEventList eventList, int bufferSize, int numberOfServers, PreemptionStrategy preemptionStrategy) Creates a preemptive queue given an event list, buffer size, number of servers and preemption strategy.

Method Summary

Modifier and Type	Method and Description
Set<J>	getJobsBeingServed() Gets the set of jobs currently being served by a server.
PreemptionStrategy	getPreemptionStrategy() Gets the preemption strategy.
protected void	preemptJob(double time, J job) Preempts a job in jobsBeingServed, taking actions depending on the preemption strategy of this queue.
protected void	queueAccessVacationDropSubClass(double time, J job) Calls super method (in order to make implementation final).
protected void	removeJobFromQueueUponDeparture(J departingJob, double time) Invokes removeJobFromQueueUponExit(J, double) (final implementation).
protected void	removeJobFromQueueUponDrop(J job, double time) Invokes removeJobFromQueueUponExit(J, double) (final implementation).
protected abstract void	removeJobFromQueueUponExit(J exitingJob, double time) Removes a job from the internal administration upon its exit from this queue (to be implemented by concrete subclasses).
protected void	removeJobFromQueueUponRevokation(J job, double time, boolean auto) Invokes removeJobFromQueueUponExit(J, double) (final implementation).
protected void	rescheduleAfterDeparture(J departedJob, double time) Invokes rescheduleAfterExit(double) (final implementation).
protected void	rescheduleAfterDrop(J job, double time) Invokes rescheduleAfterExit(double) (final implementation).
protected abstract void	rescheduleAfterExit(double time) Reschedules after a job has left this queue (to be implemented by concrete subclasses).
protected void	rescheduleAfterRevokation(J job, double time, boolean auto) Invokes rescheduleAfterExit(double) (final implementation).
protected void	resetEntitySubClass() Calls super method and removes all jobs from internal data structures.
protected void	startServiceChunk(double time, J job) Starts execution of a job in AbstractSimQueue.getJobsInServiceArea(), until it departs (if at all) or until it is preempted.
protected void	updateRemainingServiceTime(double newTime) Updates the remaining service time of executing jobs in the service area.

Methods inherited from class org.javades.jqueues.r5.entity.jq.queue.AbstractClassicSimQueue

getBufferSize, getNumberOfServers

Methods inherited from class org.javades.jqueues.r5.entity.jq.queue.AbstractSimQueue

arrive, autoRevoke, cancelDepartureEvent, cancelDepartureEvent, depart, departureFromEventList, drop, getAutoRevocationPolicy, getDepartureEvents, getDepartureEvents, getFirstJob, getFirstJobInServiceArea, getFirstJobInWaitingArea, getJobs, getJobsInServiceArea, getJobsInWaitingArea, getNumberOfJobs, getNumberOfJobsInServiceArea, getNumberOfJobsInWaitingArea, getServerAccessCredits, getServiceTimeForJob, hasJobs, hasJobsInServiceArea, hasJobsInWaitingArea, hasServerAcccessCredits, insertJobInQueueUponArrival, insertJobInQueueUponStart, isJob, isJobInServiceArea, isJobInWaitingArea, isQueueAccessVacation, registerStdOutSimQueueListener, rescheduleAfterArrival, rescheduleAfterStart, rescheduleForNewServerAccessCredits, revoke, revoke, scheduleDepartureEvent, scheduleJobArrival, setAutoRevocationPolicy, setQueueAccessVacation, setServerAccessCredits, setServerAccessCreditsSubClass, start, takeServerAccessCredit, toStringDefault, triggerPotentialNewStartArmed, unregisterStdOutSimQueueListener

Methods inherited from class org.javades.jqueues.r5.entity.AbstractSimEntity

addPendingNotification, addPendingNotification, clearAndUnlockPendingNotificationsIfLocked, delegateOperation, doAfterNotifications, doOperation, fireAndLockPendingNotifications, getEventList, getLastUpdateTime, getRegisteredDelegatedOperations, getRegisteredNotificationTypes, getRegisteredOperations, getSimEntityListeners, getUnknownNotificationTypePolicy, getUnknownOperationPolicy, isIgnoreEventListReset, notifyEventListReset, registerDelegatedOperation, registerNotificationType, registerOperation, registerPreEventHook, registerPreNotificationHook, registerPreUpdateHook, registerSimEntityListener, registerStdOutSimEntityListener, removeDelegationForOperation, resetEntity, setIgnoreEventListReset, setName, setUnknownNotificationTypePolicy, setUnknownOperationPolicy, toString, unregisterSimEntityListener, unregisterStdOutSimEntityListener, update

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.javades.jqueues.r5.entity.jq.queue.SimQueue

arrive, getAutoRevocationPolicy, getCopySimQueue, getJobs, getJobsInServiceArea, getJobsInWaitingArea, getNumberOfJobs, getNumberOfJobsInServiceArea, getNumberOfJobsInWaitingArea, getServerAccessCredits, isJob, isJobInServiceArea, isJobInWaitingArea, isQueueAccessVacation, isStartArmed, revoke, revoke, setAutoRevocationPolicy, setQueueAccessVacation, setServerAccessCredits

Methods inherited from interface org.javades.jqueues.r5.entity.SimEntity

doAfterNotifications, doOperation, getEventList, getLastUpdateTime, getRegisteredNotificationTypes, getRegisteredOperations, getSimEntityListeners, getUnknownNotificationTypePolicy, getUnknownOperationPolicy, isIgnoreEventListReset, registerSimEntityListener, resetEntity, setIgnoreEventListReset, setName, setUnknownNotificationTypePolicy, setUnknownOperationPolicy, toStringDefault, unregisterSimEntityListener, update

Methods inherited from interface org.javades.jsimulation.r5.SimEventListResetListener

notifyEventListReset

Methods inherited from interface org.javades.jqueues.r5.entity.jq.SimQoS

getQoS, getQoSClass

Field Detail

DEFAULT_PREEMPTION_STRATEGY

public static final PreemptionStrategy DEFAULT_PREEMPTION_STRATEGY

The default preemption strategy, if none was specified upon construction. The default is preemptive-resume (PreemptionStrategy.RESUME).

TOLERANCE_RST

public static final double TOLERANCE_RST

The tolerance for rounding errors in the remaining service time.

See Also:

Constant Field Values

remainingServiceTime

protected final HashMapWithPreImageAndOrderedValueSet<J extends SimJob,Double> remainingServiceTime

The mapping from jobs in AbstractSimQueue.getJobsInServiceArea() to their respective remaining service times.

The key-set of this map must always be identical to AbstractSimQueue.getJobsInServiceArea().

The special extensions to TreeMap allow for efficient determination of the pre-images of remaining service times.

jobsBeingServed

protected final Map<J extends SimJob,Double> jobsBeingServed

The jobs currently being served by a server, mapped onto the start time of this service chunk.

Constructor Detail

AbstractPreemptiveSimQueue

protected AbstractPreemptiveSimQueue(org.javades.jsimulation.r5.SimEventList eventList,
                                     int bufferSize,
                                     int numberOfServers,
                                     PreemptionStrategy preemptionStrategy)

Creates a preemptive queue given an event list, buffer size, number of servers and preemption strategy.

The constructor registers a pre-update hook that updates the remaining service time.

Parameters:

eventList - The event list to use.

bufferSize - The buffer size (non-negative), Integer.MAX_VALUE is interpreted as infinity.

numberOfServers - The number of servers (non-negative), Integer.MAX_VALUE is interpreted as infinity.

preemptionStrategy - The preemption strategy, if null, the default is used (preemptive-resume).

Throws:

IllegalArgumentException - If the event list is null.

See Also:

updateRemainingServiceTime(double)

Method Detail

getPreemptionStrategy

public final PreemptionStrategy getPreemptionStrategy()

Gets the preemption strategy.

The preemption strategy is non-null and fixed upon construction; if cannot be modified.

Returns:

The preemption strategy.

updateRemainingServiceTime

protected final void updateRemainingServiceTime(double newTime)

Updates the remaining service time of executing jobs in the service area.

This method is called as an pre-update hook, and not meant to be called from user code (in sub-classes). It is left protected for javadoc.

Parameters:

newTime - The new time.

See Also:

jobsBeingServed, remainingServiceTime, TOLERANCE_RST, AbstractSimEntity.registerPreUpdateHook(java.util.function.DoubleConsumer)

getJobsBeingServed

public final Set<J> getJobsBeingServed()

Gets the set of jobs currently being served by a server.

The assumption in this class is that a server can serve at most one job, and that the full unit-capacity of a server is used to serve the job in service (if any).

Returns:

The set of jobs currently being served by a server.

resetEntitySubClass

protected void resetEntitySubClass()

Calls super method and removes all jobs from internal data structures.

Overrides:

resetEntitySubClass in class AbstractSimQueue<J extends SimJob,Q extends AbstractPreemptiveSimQueue>

See Also:

remainingServiceTime, jobsBeingServed

queueAccessVacationDropSubClass

protected final void queueAccessVacationDropSubClass(double time,
                                                     J job)

Calls super method (in order to make implementation final).

Overrides:

queueAccessVacationDropSubClass in class AbstractSimQueue<J extends SimJob,Q extends AbstractPreemptiveSimQueue>

Parameters:

time - The time the job was dropped, i.e., the current time.

job - The dropped job.

See Also:

AbstractSimQueue.arrive(double, J), AbstractSimQueue.setQueueAccessVacation(double, boolean)

preemptJob

protected final void preemptJob(double time,
                                J job)

Preempts a job in jobsBeingServed, taking actions depending on the preemption strategy of this queue.

Parameters:

time - The (current) time.

job - The job to preempt.

Throws:

IllegalArgumentException - If the job is null or not in jobsBeingServed.

UnsupportedOperationException - If the preemption strategy is PreemptionStrategy.REDRAW of PreemptionStrategy.CUSTOM.

See Also:

jobsBeingServed, remainingServiceTime, getPreemptionStrategy(), AbstractSimQueue.drop(J, double), AbstractSimQueue.cancelDepartureEvent(org.javades.jqueues.r5.entity.jq.SimJQEvent.Departure<J, Q>), AbstractSimQueue.getServiceTimeForJob(J), AbstractSimQueue.depart(double, J)

startServiceChunk

protected final void startServiceChunk(double time,
                                       J job)

Starts execution of a job in AbstractSimQueue.getJobsInServiceArea(), until it departs (if at all) or until it is preempted.

The job to execute departs immediately if its remaining service time is zero; or is finite and time itself is at positive or negative infinity. No departure event is scheduled if the job has infinite required service time.

Parameters:

time - The (current) time.

job - The job to start executing.

Throws:

IllegalArgumentException - If the job is null, not in the service area, or already being executed.

See Also:

jobsBeingServed, remainingServiceTime, TOLERANCE_RST, AbstractSimQueue.scheduleDepartureEvent(double, J), AbstractSimQueue.depart(double, J)

removeJobFromQueueUponDrop

protected final void removeJobFromQueueUponDrop(J job,
                                                double time)

Invokes removeJobFromQueueUponExit(J, double) (final implementation).

Specified by:

removeJobFromQueueUponDrop in class AbstractSimQueue<J extends SimJob,Q extends AbstractPreemptiveSimQueue>

Parameters:

job - The job that is to be dropped.

time - The current time (i.e., drop time of the job).

See Also:

AbstractSimQueue.drop(J, double), AbstractSimQueue.rescheduleAfterDrop(J, double)

rescheduleAfterDrop

protected final void rescheduleAfterDrop(J job,
                                         double time)

Invokes rescheduleAfterExit(double) (final implementation).

Specified by:

rescheduleAfterDrop in class AbstractSimQueue<J extends SimJob,Q extends AbstractPreemptiveSimQueue>

Parameters:

job - The jobs that was dropped.

time - The current time (i.e., drop time of the job).

See Also:

AbstractSimQueue.drop(J, double), AbstractSimQueue.removeJobFromQueueUponDrop(J, double)

removeJobFromQueueUponRevokation

protected final void removeJobFromQueueUponRevokation(J job,
                                                      double time,
                                                      boolean auto)

Invokes removeJobFromQueueUponExit(J, double) (final implementation).

Specified by:

removeJobFromQueueUponRevokation in class AbstractSimQueue<J extends SimJob,Q extends AbstractPreemptiveSimQueue>

Parameters:

job - The job that is to be revoked.

time - The current time (i.e., revocation time of the job).

auto - Whether or not this applies to an auto-revocation.

See Also:

AbstractSimQueue.revoke(double, J, boolean), AbstractSimQueue.autoRevoke(double, J), AbstractSimQueue.rescheduleAfterRevokation(J, double, boolean), SimQueue.AutoRevocationPolicy

rescheduleAfterRevokation

protected final void rescheduleAfterRevokation(J job,
                                               double time,
                                               boolean auto)

Invokes rescheduleAfterExit(double) (final implementation).

Specified by:

rescheduleAfterRevokation in class AbstractSimQueue<J extends SimJob,Q extends AbstractPreemptiveSimQueue>

Parameters:

job - The jobs that was successfully revoked.

time - The current time (i.e., revocation time of the job).

auto - Whether or not this applies to an auto-revocation.

See Also:

AbstractSimQueue.revoke(double, J, boolean), AbstractSimQueue.autoRevoke(double, J), AbstractSimQueue.removeJobFromQueueUponRevokation(J, double, boolean), SimQueue.AutoRevocationPolicy

removeJobFromQueueUponDeparture

protected final void removeJobFromQueueUponDeparture(J departingJob,
                                                     double time)

Invokes removeJobFromQueueUponExit(J, double) (final implementation).

Specified by:

removeJobFromQueueUponDeparture in class AbstractSimQueue<J extends SimJob,Q extends AbstractPreemptiveSimQueue>

Parameters:

departingJob - The job that departs.

time - The departure (current) time.

See Also:

AbstractSimQueue.depart(double, J), AbstractSimQueue.rescheduleAfterDeparture(J, double)

rescheduleAfterDeparture

protected final void rescheduleAfterDeparture(J departedJob,
                                              double time)

Invokes rescheduleAfterExit(double) (final implementation).

Specified by:

rescheduleAfterDeparture in class AbstractSimQueue<J extends SimJob,Q extends AbstractPreemptiveSimQueue>

Parameters:

departedJob - The departed job.

time - The departure (current) time.

See Also:

AbstractSimQueue.depart(double, J), AbstractSimQueue.removeJobFromQueueUponDeparture(J, double)

removeJobFromQueueUponExit

protected abstract void removeJobFromQueueUponExit(J exitingJob,
                                                   double time)

Removes a job from the internal administration upon its exit from this queue (to be implemented by concrete subclasses).

The job may have been dropped, successfully revoked, or it may just depart.

This is the central entry point for removeJobFromQueueUponDrop(J, double), removeJobFromQueueUponRevokation(J, double, boolean), removeJobFromQueueUponDeparture(J, double). Implementations must take into account the cancellation of departure (and other) events.

Parameters:

exitingJob - The job leaving.

time - The (current) time.

See Also:

removeJobFromQueueUponDrop(J, double), removeJobFromQueueUponRevokation(J, double, boolean), removeJobFromQueueUponDeparture(J, double), rescheduleAfterExit(double), AbstractSimQueue.getDepartureEvents()

rescheduleAfterExit

protected abstract void rescheduleAfterExit(double time)

Reschedules after a job has left this queue (to be implemented by concrete subclasses).

The job may have been dropped, successfully been revoked, or departed.

This is the central entry point for rescheduleAfterDrop(J, double), rescheduleAfterRevokation(J, double, boolean), rescheduleAfterDeparture(J, double). Implementations must typically check whether to start a new service chunk startServiceChunk(double, J).

Parameters:

time - The (current) time.

See Also:

rescheduleAfterDrop(J, double), rescheduleAfterRevokation(J, double, boolean), rescheduleAfterDeparture(J, double), removeJobFromQueueUponExit(J, double), startServiceChunk(double, J)