Package ptolemy.domains.de.lib

Class Register

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.actor.lib.Transformer

ptolemy.domains.de.lib.MostRecent

ptolemy.domains.de.lib.Register

All Implemented Interfaces:

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

public class Register
extends MostRecent

A register is a stateful actor with a trigger port that accepts read requests.

In the fire() method, if there is an event on the trigger input port, this actor will produce an output event. The value of the output event will be the previously recorded event from the input port, or the value of the initialValue parameter if there has been no previous input event. If, however, initialValue contains no value, then no output will be produced. In the postfire() method, if there is an input event on the input port, then its value is recorded to be used in future firings as the value of the output.

The inputs can be of any token type, but the output port is constrained to be of a type at least that of the input port and the initialValue parameter.

This class extends MostRecent. Unlike its base class, this actor can be used to break dependencies in a feedback loop in that the input tokens are consumed from the input ports after the outputs are generated. Another difference is that the Register actor can be fired when either the trigger port or the input port has a token, while the Sampler can only be fired when the trigger port receives a token.

Both the input port and the output port are multiports. Generally, their widths should match. Otherwise, if the width of the input is greater than the width of the output, the extra input tokens will not appear on any output, although they will be consumed from the input port. If the width of the output is greater than that of the input, then the last few channels of the output will never emit tokens.

Note: If the width of the input changes during execution, then the most recent inputs are forgotten, as if the execution of the model were starting over.

Since:

Ptolemy II 4.1

Version:

$Id$

Author:

Edward A. Lee, Haiyang Zheng

See Also:

MostRecent

Pt.AcceptedRating:

Red (eal)

Pt.ProposedRating:

Yellow (eal)

Nested Class Summary

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

Entity.ContainedObjectsIterator

Field Summary

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

_lastInputs, initialValue, trigger

Fields inherited from class ptolemy.actor.lib.Transformer

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	Description
Register(CompositeEntity container, java.lang.String name)	Construct an actor with the given container and name.

Method Summary

Modifier and Type	Method	Description
void	declareDelayDependency()	Declare that the output does not depend on the input in a firing.
void	fire()	If there is a token in the trigger port, emit the previously seen inputs from the input port.
boolean	isStrict()	Indicate that this actor can fire even if the inputs are not known.
boolean	postfire()	Read and record the inputs.
boolean	prefire()	Return true if there is any token in the input or the trigger port.

Methods inherited from class ptolemy.domains.de.lib.MostRecent

_containedTypeConstraints, attributeChanged, clone, initialize, readInputs, sendOutputIfTriggered, wrapup

Methods inherited from class ptolemy.actor.TypedAtomicActor

_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, iterate, newReceiver, outputPortList, 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.kernel.util.Derivable

getDerivedLevel, getDerivedList, propagateValue

Methods inherited from interface ptolemy.actor.Executable

isFireFunctional, iterate, 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

Constructor Detail

Register

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

Construct an actor with the given container and name.

Parameters:

container - The container.

name - The name of this actor.

Throws:

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

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

Method Detail

declareDelayDependency

public void declareDelayDependency()
                            throws IllegalActionException

Declare that the output does not depend on the input 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 a token in the trigger port, emit the previously seen inputs from the input port. If there has been no previous input tokens, but the initialValue parameter has been set, emit the value of the initialValue parameter. Otherwise, emit nothing.

Specified by:

fire in interface Executable

Overrides:

fire in class MostRecent

Throws:

IllegalActionException - If there is no director.

isStrict

public boolean isStrict()

Indicate that this actor can fire even if the inputs are not known. This enables the actor to be used in SR and Continuous.

Specified by:

isStrict in interface Executable

Overrides:

isStrict in class AtomicActor<TypedIOPort>

Returns:

False.

postfire

public boolean postfire()
                 throws IllegalActionException

Read and record the inputs.

Specified by:

postfire in interface Executable

Overrides:

postfire in class AtomicActor<TypedIOPort>

Returns:

What the superclass returns.

Throws:

IllegalActionException - If the superclass throws it.

prefire

public boolean prefire()
                throws IllegalActionException

Return true if there is any token in the input or the trigger port. This ensures that if an input is provided without a trigger, it will get recorded.

Specified by:

prefire in interface Executable

Overrides:

prefire in class MostRecent

Returns:

True if this actor is ready for firing, false otherwise.

Throws:

IllegalActionException - If the base class throws it.