ptolemy.domains.de.lib

Class Server

java.lang.Object

ptolemy.kernel.util.NamedObj

ptolemy.kernel.InstantiableNamedObj

ptolemy.kernel.Entity<T>

ptolemy.kernel.ComponentEntity<T>

ptolemy.actor.AtomicActor<TypedIOPort>

ptolemy.actor.TypedAtomicActor

ptolemy.domains.de.kernel.DEActor

ptolemy.domains.de.lib.DETransformer

ptolemy.domains.de.lib.Server

All Implemented Interfaces:

java.lang.Cloneable, Actor, Executable, FiringsRecordable, Initializable, SequenceActor, TimedActor, TypedActor, Changeable, Debuggable, DebugListener, Derivable, Instantiable, ModelErrorHandler, MoMLExportable, Moveable, Nameable

public class Server
extends DETransformer

This actor models a preemptive server with a fixed or variable service time. A server is either busy (serving a customer) or not busy at any given time. If an input arrives when the server is not busy, then the input token is produced on the output with a delay given by the serviceTime parameter. If an input arrives while the server is busy, then that input is queued until the server becomes free, at which point it is produced on the output with a delay given by the serviceTime parameter value at the time that the input arrived. If several inputs arrive while the server is busy, then they are served in an order determined by the value of the priority parameter at the time of arrival of the input, and for inputs with identical priorities, on a first-come, first-served basis. On every firing, produce an output indicating the final queue size.

The service time and priority used for a job are the most recently arrived values prior to or simultaneous with the arrival of the job (not with the time at which service begins). Thus, if you want each job to have an independent service time or priority, you should provide each parameter as an input synchronized with each new job arrival.

Since:

Ptolemy II 0.3

Version:

$Id$

Author:

Lukito Muliadi, Edward A. Lee, Haiyang Zheng

See Also:

TimeDelay

Pt.AcceptedRating:

Yellow (hyzheng)

Pt.ProposedRating:

Yellow (hyzheng)

Nested Class Summary

Nested classes/interfaces inherited from class ptolemy.kernel.Entity

Entity.ContainedObjectsIterator

Field Summary

Fields

Modifier and Type	Field and Description
protected Time	_nextTimeFree Next time the server becomes free.
protected long	_queueCounter The counter for tie-breaking the queue by insertion order.
protected java.util.TreeMap<java.lang.Double,java.util.PriorityQueue<ptolemy.domains.de.lib.Server.Job>>	_queues
protected int	_queueSize
Parameter	capacity The capacity of the queue.
PortParameter	priority The priority.
PortParameter	serviceTime The service time.
TypedIOPort	size The current size of the queue.

Fields inherited from class ptolemy.domains.de.lib.DETransformer

input, output

Fields inherited from class ptolemy.actor.TypedAtomicActor

_typesValid

Fields inherited from class ptolemy.actor.AtomicActor

_actorFiringListeners, _initializables, _notifyingActorFiring, _stopRequested

Fields inherited from class ptolemy.kernel.util.NamedObj

_changeListeners, _changeLock, _changeRequests, _debugging, _debugListeners, _deferChangeRequests, _elementName, _isPersistent, _verbose, _workspace, ATTRIBUTES, CLASSNAME, COMPLETE, CONTENTS, DEEP, FULLNAME, LINKS

Fields inherited from interface ptolemy.actor.Executable

COMPLETED, NOT_READY, STOP_ITERATING

Constructor Summary

Constructors

Constructor and Description
Server(CompositeEntity container, java.lang.String name) Construct an actor with the specified container and name.

Method Summary

Modifier and Type	Method and Description
void	attributeChanged(Attribute attribute) If the attribute is serviceTime, then ensure that the value is non-negative, and if the attribute is capacity, then change the capacity of the queue.
java.lang.Object	clone(Workspace workspace) Clone the actor into the specified workspace.
void	declareDelayDependency() Declare that the output does not depend on the input, serviceTime, and priority, in a firing.
void	fire() If there is input, read it and put it in the queue.
void	initialize() Reset the states of the server to indicate that the server is ready to serve.
boolean	postfire() If the server is free and there is at least one token in the queue, request a firing at the current time plus the service time.
protected int	queueSize()
void	wrapup() Clear the queue so that the capacity can be changed.

Methods inherited from class ptolemy.actor.TypedAtomicActor

_containedTypeConstraints, _customTypeConstraints, _defaultTypeConstraints, _fireAt, _fireAt, attributeTypeChanged, clone, isBackwardTypeInferenceEnabled, newPort, typeConstraintList, typeConstraints

Methods inherited from class ptolemy.actor.AtomicActor

_actorFiring, _actorFiring, _declareDelayDependency, addActorFiringListener, addInitializable, connectionsChanged, createReceivers, getCausalityInterface, getDirector, getExecutiveDirector, getManager, inputPortList, isFireFunctional, isStrict, iterate, newReceiver, outputPortList, prefire, preinitialize, pruneDependencies, recordFiring, removeActorFiringListener, removeDependency, removeInitializable, setContainer, stop, stopFire, terminate

Methods inherited from class ptolemy.kernel.ComponentEntity

_adjustDeferrals, _checkContainer, _getContainedObject, _propagateExistence, getContainer, instantiate, isAtomic, isOpaque, moveDown, moveToFirst, moveToIndex, moveToLast, moveUp, propagateExistence, setName

Methods inherited from class ptolemy.kernel.Entity

_addPort, _description, _exportMoMLContents, _removePort, _validateSettables, connectedPortList, connectedPorts, containedObjectsIterator, getAttribute, getPort, getPorts, linkedRelationList, linkedRelations, portList, removeAllPorts, setClassDefinition, uniqueName

Methods inherited from class ptolemy.kernel.InstantiableNamedObj

_setParent, exportMoML, getChildren, getElementName, getParent, getPrototypeList, isClassDefinition, isWithinClassDefinition

Methods inherited from class ptolemy.kernel.util.NamedObj

_addAttribute, _adjustOverride, _attachText, _cloneFixAttributeFields, _containedDecorators, _copyChangeRequestList, _debug, _debug, _debug, _debug, _debug, _executeChangeRequests, _getIndentPrefix, _isMoMLSuppressed, _markContentsDerived, _notifyHierarchyListenersAfterChange, _notifyHierarchyListenersBeforeChange, _propagateValue, _removeAttribute, _splitName, _stripNumericSuffix, addChangeListener, addDebugListener, addHierarchyListener, attributeDeleted, attributeList, attributeList, decorators, deepContains, depthInHierarchy, description, description, event, executeChangeRequests, exportMoML, exportMoML, exportMoML, exportMoML, exportMoMLPlain, getAttribute, getAttributes, getChangeListeners, getClassName, getDecoratorAttribute, getDecoratorAttributes, getDerivedLevel, getDerivedList, getDisplayName, getFullName, getModelErrorHandler, getName, getName, getSource, handleModelError, isDeferringChangeRequests, isOverridden, isPersistent, lazyContainedObjectsIterator, message, notifyOfNameChange, propagateValue, propagateValues, removeAttribute, removeChangeListener, removeDebugListener, removeHierarchyListener, requestChange, setClassName, setDeferringChangeRequests, setDerivedLevel, setDisplayName, setModelErrorHandler, setPersistent, setSource, sortContainedObjects, toplevel, toString, validateSettables, workspace

Methods inherited from class java.lang.Object

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

Methods inherited from interface ptolemy.actor.Actor

createReceivers, getCausalityInterface, getDirector, getExecutiveDirector, getManager, inputPortList, newReceiver, outputPortList

Methods inherited from interface ptolemy.actor.Executable

isFireFunctional, isStrict, iterate, prefire, stop, stopFire, terminate

Methods inherited from interface ptolemy.actor.Initializable

addInitializable, preinitialize, removeInitializable

Methods inherited from interface ptolemy.kernel.util.Nameable

description, getContainer, getDisplayName, getFullName, getName, getName, setName

Methods inherited from interface ptolemy.kernel.util.Derivable

getDerivedLevel, getDerivedList, propagateValue

Field Detail

capacity

public Parameter capacity

The capacity of the queue. If the value is positive, then it specifies the capacity of the queue. If it is negative or 0, then it specifies that the capacity is infinite. This is an integer with default 0.

size

public TypedIOPort size

The current size of the queue. This port produces an output whenever the size changes. It has type int.

serviceTime

public PortParameter serviceTime

The service time. This is a double with default 1.0. It is required to be non-negative.

priority

public PortParameter priority

The priority. This is a double with default 0.0. A higher priority implies the task has precedence over tasks with lower priority values.

_nextTimeFree

protected Time _nextTimeFree

Next time the server becomes free.

_queues

protected java.util.TreeMap<java.lang.Double,java.util.PriorityQueue<ptolemy.domains.de.lib.Server.Job>> _queues

_queueSize

protected int _queueSize

_queueCounter

protected long _queueCounter

The counter for tie-breaking the queue by insertion order.

Constructor Detail

Server

public Server(CompositeEntity container,
              java.lang.String name)
       throws NameDuplicationException,
              IllegalActionException

Construct an actor with the specified container and name.

Parameters:

container - The composite entity to contain this one.

name - The name of this actor.

Throws:

IllegalActionException - If the entity cannot be contained by the proposed container.

NameDuplicationException - If the container already has an actor with this name.

Method Detail

attributeChanged

public void attributeChanged(Attribute attribute)
                      throws IllegalActionException

If the attribute is serviceTime, then ensure that the value is non-negative, and if the attribute is capacity, then change the capacity of the queue. If the size of the queue currently exceeds the specified capacity, then throw an exception.

Overrides:

attributeChanged in class NamedObj

Parameters:

attribute - The attribute that changed.

Throws:

IllegalActionException - If the service time is negative.

clone

public java.lang.Object clone(Workspace workspace)
                       throws java.lang.CloneNotSupportedException

Clone the actor into the specified workspace. Set a type constraint that the output type is the same as the that of input.

Overrides:

clone in class TypedAtomicActor

Parameters:

workspace - The workspace for the new object.

Returns:

A new actor.

Throws:

java.lang.CloneNotSupportedException - If a derived class has has an attribute that cannot be cloned.

See Also:

NamedObj.exportMoML(Writer, int, String), NamedObj.setDeferringChangeRequests(boolean)

declareDelayDependency

public void declareDelayDependency()
                            throws IllegalActionException

Declare that the output does not depend on the input, serviceTime, and priority, in a firing.

Overrides:

declareDelayDependency in class AtomicActor<TypedIOPort>

Throws:

IllegalActionException - If the causality interface cannot be computed.

See Also:

AtomicActor.getCausalityInterface()

fire

public void fire()
          throws IllegalActionException

If there is input, read it and put it in the queue. If the service time has expired for a token currently in the queue, then send that token on the output. Produce an output indicating the current queue size.

Specified by:

fire in interface Executable

Overrides:

fire in class AtomicActor<TypedIOPort>

Throws:

IllegalActionException - If the serviceTime or priority is invalid, or if an error occurs sending the output token.

queueSize

protected int queueSize()

initialize

public void initialize()
                throws IllegalActionException

Reset the states of the server to indicate that the server is ready to serve.

Specified by:

initialize in interface Initializable

Overrides:

initialize in class AtomicActor<TypedIOPort>

Throws:

IllegalActionException - If the base class throws it.

postfire

public boolean postfire()
                 throws IllegalActionException

If the server is free and there is at least one token in the queue, request a firing at the current time plus the service time.

Specified by:

postfire in interface Executable

Overrides:

postfire in class AtomicActor<TypedIOPort>

Returns:

Whatever the superclass returns.

Throws:

IllegalActionException - If there is no director.

wrapup

public void wrapup()
            throws IllegalActionException

Clear the queue so that the capacity can be changed.

Specified by:

wrapup in interface Initializable

Overrides:

wrapup in class AtomicActor<TypedIOPort>

Throws:

IllegalActionException - If the superclass throws it.