ptolemy.domains.continuous.lib
Class ZeroOrderHold

java.lang.Object
  ptolemy.kernel.util.NamedObj
      ptolemy.kernel.InstantiableNamedObj
          ptolemy.kernel.Entity
              ptolemy.kernel.ComponentEntity
                  ptolemy.actor.AtomicActor
                      ptolemy.actor.TypedAtomicActor
                          ptolemy.actor.lib.Transformer
                              ptolemy.domains.continuous.lib.ZeroOrderHold

All Implemented Interfaces:

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

public class ZeroOrderHold
extends Transformer

Convert discrete events at the input to a continuous-time signal at the output by holding the value of the discrete event until the next discrete event arrives. Specifically, on each firing, if an input is present, then record the value of the input. Then produce the recorded value. This actor will throw an exception if the input is not purely discrete. Specifically, this means that when the input is present, the step size of the solver has to be 0.0.

Since:

Ptolemy II 6.0

Version:

$Id: ZeroOrderHold.java 57046 2010-01-27 23:35:53Z cxh $

Author:

Edward A. Lee, Haiyang Zheng

See Also:

Serialized Form

Accepted Rating:

Red (hyzheng)

Proposed Rating:

Green (hyzheng)

Nested Class Summary

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

Entity.ContainedObjectsIterator

Field Summary

private Token	_lastToken
Parameter	defaultValue Default output before any input has received.

Fields inherited from class ptolemy.actor.lib.Transformer

input, output

Fields inherited from class ptolemy.actor.AtomicActor

_actorFiringListeners, _initializables, _notifyingActorFiring, _stopRequested

Fields inherited from class ptolemy.kernel.util.NamedObj

_changeListeners, _changeLock, _changeRequests, _debugging, _debugListeners, _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

ZeroOrderHold(CompositeEntity container, java.lang.String name)
Construct an actor in the specified container with the specified name.

Method Summary

void	fire() Output the latest token consumed from the consumeCurrentEvents() call.
void	initialize() Initialize token.
java.util.Set<Inequality>	typeConstraints() Override the method in the base class so that the type constraint for the initialValue parameter will be set if it contains a value.

Methods inherited from class ptolemy.actor.TypedAtomicActor

_addPort, _fireAt, _fireAt, attributeTypeChanged, clone, newPort, typeConstraintList

Methods inherited from class ptolemy.actor.AtomicActor

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

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

_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, _debug, _debug, _debug, _debug, _debug, _getIndentPrefix, _isMoMLSuppressed, _markContentsDerived, _propagateValue, _recordDecoratedAttributes, _removeAttribute, _splitName, _stripNumericSuffix, addChangeListener, addDebugListener, attributeChanged, attributeList, attributeList, 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, propagateValue, propagateValues, removeChangeListener, removeDebugListener, 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, postfire, prefire, stop, stopFire, terminate

Methods inherited from interface ptolemy.actor.Initializable

addInitializable, preinitialize, removeInitializable, wrapup

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

defaultValue

public Parameter defaultValue

Default output before any input has received. The default is empty, indicating that no output is produced until an input is received. The type of the output is set to at least the type of this parameter (and also at least the type of the input).

_lastToken

private Token _lastToken

Constructor Detail

ZeroOrderHold

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

Construct an actor in the specified container with the specified name. The name must be unique within the container or an exception is thrown. The container argument must not be null, or a NullPointerException will be thrown.

Parameters:

container - The subsystem that this actor is lived in

name - The actor's name

Throws:

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

NameDuplicationException - If name coincides with an entity already in the container.

Method Detail

fire

public void fire()
          throws IllegalActionException

Output the latest token consumed from the consumeCurrentEvents() call.

Specified by:

fire in interface Executable

Overrides:

fire in class AtomicActor

Throws:

IllegalActionException - If the token cannot be sent.

initialize

public void initialize()
                throws IllegalActionException

Initialize token. If there is no input, the initial token is a Double Token with the value specified by the defaultValue parameter.

Specified by:

initialize in interface Initializable

Overrides:

initialize in class AtomicActor

Throws:

IllegalActionException - If thrown by the super class.

typeConstraints

public java.util.Set<Inequality> typeConstraints()

Override the method in the base class so that the type constraint for the initialValue parameter will be set if it contains a value.

Specified by:

typeConstraints in interface TypedActor

Overrides:

typeConstraints in class TypedAtomicActor

Returns:

a list of Inequality objects.

See Also:

Inequality