ptolemy.actor.lib
Class Counter

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.Counter

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 Counter
extends TypedAtomicActor

This actor implements an up-down counter of received tokens. Whenever a token is received from the increment input, the internal counter is incremented. Whenever a token is received from the decrement port, the internal counter is decremented. Whenever a token is received from either input port, a token is created on the output port with the integer value of the current count. At most one token will be consumed from each input during each firing. If a token is present on both input ports during any firing, then the increment and the decrement will cancel out, and only one output token will be produced.

Since:

Ptolemy II 2.0

Version:

$Id: Counter.java 57040 2010-01-27 20:52:32Z cxh $

Author:

Steve Neuendorffer

See Also:

Serialized Form

Accepted Rating:

Yellow (neuendor)

Proposed Rating:

Yellow (neuendor)

Nested Class Summary

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

Entity.ContainedObjectsIterator

Field Summary

private boolean	_consumed
private int	_count
private int	_latestCount
TypedIOPort	decrement The decrement port.
TypedIOPort	increment The increment port.
TypedIOPort	output The output port with type IntToken.

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

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

Method Summary

void	fire() Consume at most one token from each input and update the counter appropriately.
void	initialize() Reset the count of inputs to zero.
boolean	postfire() Record the most recent output count as the actual count.

Methods inherited from class ptolemy.actor.TypedAtomicActor

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

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, 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, 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

increment

public TypedIOPort increment

The increment port. If this input port receives a token, then the counter is incremented. The port has type general.

decrement

public TypedIOPort decrement

The decrement port. If this input port receives a token, then the counter is decremented. The port has type general.

output

public TypedIOPort output

The output port with type IntToken.

_count

private int _count

_latestCount

private int _latestCount

_consumed

private boolean _consumed

Constructor Detail

Counter

public Counter(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

fire

public void fire()
          throws IllegalActionException

Consume at most one token from each input and update the counter appropriately. Send the current value of the counter to the output. If there are no input tokens available, no output will be produced. If a token is consumed from only the increment port the output value will be one more than the previous output value. If a token consumed from only the decrement port the output value will be one less than the previous output value. If a token is consumed from both input ports, then the output value will be the same as the previous output value. If the fire method is invoked multiple times in one iteration, then only the input read on the last invocation in the iteration will affect future outputs of the counter.

Specified by:

fire in interface Executable

Overrides:

fire in class AtomicActor

Throws:

IllegalActionException - If there is no director.

initialize

public void initialize()
                throws IllegalActionException

Reset the count of inputs to zero.

Specified by:

initialize in interface Initializable

Overrides:

initialize in class AtomicActor

Throws:

IllegalActionException - If the parent class throws it.

postfire

public boolean postfire()
                 throws IllegalActionException

Record the most recent output count as the actual count.

Specified by:

postfire in interface Executable

Overrides:

postfire in class AtomicActor

Returns:

True if execution can continue into the next iteration.

Throws:

IllegalActionException - If the base class throws it.