ptolemy.domains.de.lib
Class Sampler

java.lang.Object
  ptolemy.kernel.util.NamedObj
      ptolemy.kernel.InstantiableNamedObj
          ptolemy.kernel.Entity
              ptolemy.kernel.ComponentEntity
                  ptolemy.actor.AtomicActor
                      ptolemy.actor.TypedAtomicActor
                          ptolemy.domains.de.kernel.DEActor
                              ptolemy.domains.de.lib.DETransformer
                                  ptolemy.domains.de.lib.Sampler

All Implemented Interfaces:

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

Direct Known Subclasses:

Register

public class Sampler
extends DETransformer

Output the most recent input token when the trigger port receives a token. If no token has been received on the input port when a token is received on the trigger port, then the value of the initialValue parameter is produced. If, however, the initialValue parameter contains no value, then no output is produced. 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 (if it has a value).

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.

This actor is similar to the Inhibit actor in that it modifies a stream of events based on the presence or absence of events from another input. This actor reacts to the presence of the other event, whereas Inhibit reacts to the absence of it.

This actor is different from the Register actor in that the input tokens are consumed from the input ports before the outputs are generated.

Since:

Ptolemy II 0.3

Version:

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

Author:

Jie Liu, Edward A. Lee, Steve Neuendorffer, Elaine Cheong

See Also:

Inhibit, Register, Serialized Form

Accepted Rating:

Yellow (eal)

Proposed Rating:

Yellow (eal)

Nested Class Summary

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

Entity.ContainedObjectsIterator

Field Summary

protected Token[]	_lastInputs The recorded inputs last seen.
Parameter	initialValue The value that is output when no input has yet been received.
TypedIOPort	trigger The trigger port, which has undeclared type.

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

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

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

Method Summary

void	attributeChanged(Attribute attribute) If the initialValue parameter is the argument, then reset the current output to match the new value.
java.lang.Object	clone(Workspace workspace) Clone the actor into the specified workspace.
void	fire() Consume all the tokens in the input ports and record them.
void	initialize() Clear the cached input tokens.
boolean	prefire() If there is no input on the trigger port, return false, indicating that this actor does not want to fire.
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, connectionsChanged, createReceivers, declareDelayDependency, getCausalityInterface, getDirector, getExecutiveDirector, getManager, inputPortList, isFireFunctional, isStrict, iterate, newReceiver, outputPortList, postfire, 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, 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, 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

trigger

public TypedIOPort trigger

The trigger port, which has undeclared type. If this port receives a token, then the most recent token from the input port will be emitted on the output port.

initialValue

public Parameter initialValue

The value that is output when no input has yet been received. If this is changed during execution, then the output will match the new value until another input is received. The type should be the same as the input port.

See Also:

typeConstraints()

_lastInputs

protected Token[] _lastInputs

The recorded inputs last seen.

Constructor Detail

Sampler

public Sampler(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

attributeChanged

public void attributeChanged(Attribute attribute)
                      throws IllegalActionException

If the initialValue parameter is the argument, then reset the current output to match the new value.

Overrides:

attributeChanged in class NamedObj

Parameters:

attribute - The attribute that changed.

Throws:

IllegalActionException - If the change is not acceptable to this container (not thrown in this base class).

clone

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

Clone the actor into the specified workspace. This calls the base class and then sets the ports.

Overrides:

clone in class AtomicActor

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)

fire

public void fire()
          throws IllegalActionException

Consume all the tokens in the input ports and record them. If there is a token in the trigger port, emit the most recent token from the input port. If there has been no input token, 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 AtomicActor

Throws:

IllegalActionException - If there is no director.

prefire

public boolean prefire()
                throws IllegalActionException

If there is no input on the trigger port, return false, indicating that this actor does not want to fire. This has the effect of leaving input values in the input ports, if there are any.

Specified by:

prefire in interface Executable

Overrides:

prefire in class AtomicActor

Returns:

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

Throws:

IllegalActionException - If there is no director.

initialize

public void initialize()
                throws IllegalActionException

Clear the cached input tokens.

Specified by:

initialize in interface Initializable

Overrides:

initialize in class AtomicActor

Throws:

IllegalActionException - If there is no director.

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