Package ptolemy.actor.lib

Class Source

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.Source

All Implemented Interfaces:

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

Direct Known Subclasses:

ActorWithPrivateParameter, AudioReader, CSPSource, DatabaseQuery, DatabaseSelect, DummySource, EventButton, GetCausalityInterface, HadamardCode, ImageReader, ImageSequence, JAIConstant, JAIImageReader, JopReadPort, JopSerialRead, LimitedFiringSource, LineReader, ModelGenerator, MovieReader, ObjectTokenSource, PGMReader, RandomSource, Reader, SecretKey, SliderSource, SplitReader, SQLStatement, StreamLoader, TimedSource, Undefined, URLReader, VideoCamera, WallClockTime

public abstract class Source
extends TypedAtomicActor

Base for simple data sources. This provides an output port and a trigger input port, both exposed as public variables. The trigger port is a multiport with undeclared type, meaning that you can supply it with any data type. The trigger port can also be left unconnected. The purpose of the trigger input is to (optionally) supply events that cause the actor to fire. If the port is connected to something, then this actor will check it for a token and return false from prefire() if there is no token. each channel of the trigger input, if any, and then discards the token.

Some derived classes may attach additional significance to an input on the trigger port. For example, they might fix the type and attach some significance to the value. Note that it is not recommend to use getWidth() on the port to determine whether the port is connected, since the width may be greater than zero even if there is no actual source of data. This can occur, for example, if a trigger port is connected to the inside of a port of an opaque composite actor, and there is nothing connected to the outside of that port. It is not recommended to make the behavior of an actor dependent on a global property such as whether there is ultimately a source of data.

Any type of data on is accepted on the trigger port, therefore no type is declared. Instead, the type resolution algorithm finds the least fixed point. If backward type inference is enabled, and no type has been declared for the trigger, it is constrained to be equal to BaseType.GENERAL. This will result in upstream ports resolving to the most general type rather than the most specific.

Since:

Ptolemy II 0.3

Version:

$Id$

Author:

Edward A. Lee

Pt.AcceptedRating:

Green (bilung)

Pt.ProposedRating:

Green (eal)

Nested Class Summary

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

Entity.ContainedObjectsIterator

Field Summary

Fields

Modifier and Type	Field	Description
protected boolean	_triggered	Indicator of whether trigger inputs have arrived since the last output.
TypedIOPort	output	The output port.
TypedIOPort	trigger	The trigger port.

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

Method Summary

Modifier and Type	Method	Description
protected java.util.Set<Inequality>	_customTypeConstraints()	Set the input port greater than or equal to BaseType.GENERAL in case backward type inference is enabled and the input port has no type declared.
void	fire()	Read at most one input token from each channel of the trigger input and discard it.
boolean	prefire()	If the trigger input is connected and it has no input or an unknown state, then return false.

Methods inherited from class ptolemy.actor.TypedAtomicActor

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

Methods inherited from class ptolemy.actor.AtomicActor

_actorFiring, _actorFiring, _declareDelayDependency, addActorFiringListener, addInitializable, connectionsChanged, createReceivers, declareDelayDependency, getCausalityInterface, getDirector, getExecutiveDirector, getManager, initialize, 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

_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, attributeChanged, 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, isStrict, iterate, postfire, stop, stopFire, terminate

Methods inherited from interface ptolemy.actor.Initializable

addInitializable, initialize, preinitialize, removeInitializable, wrapup

Methods inherited from interface ptolemy.kernel.util.Nameable

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

Field Detail

output

public TypedIOPort output

The output port. The type of this port is unspecified. Derived classes may set it.

trigger

public TypedIOPort trigger

The trigger port. The type of this port is undeclared, meaning that it will resolve to any data type.

_triggered

protected transient boolean _triggered

Indicator of whether trigger inputs have arrived since the last output.

Constructor Detail

Source

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

Construct an actor with the given container and name. The output and trigger ports are also constructed.

Parameters:

container - The container.

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

fire

public void fire()
          throws IllegalActionException

Read at most one input token from each channel of the trigger input and discard it. If the trigger input is not connected or has no actual sources (it might be connected to other inputs, for example, or to an unconnected input port at a higher level in the hierarchy) then this method does nothing. Derived classes should be sure to call super.fire(), or to consume the trigger input tokens themselves, so that they aren't left unconsumed.

Specified by:

fire in interface Executable

Overrides:

fire in class AtomicActor<TypedIOPort>

Throws:

IllegalActionException - Not thrown in this base class.

prefire

public boolean prefire()
                throws IllegalActionException

If the trigger input is connected and it has no input or an unknown state, then return false. Otherwise, return true.

Specified by:

prefire in interface Executable

Overrides:

prefire in class AtomicActor<TypedIOPort>

Returns:

True, unless the trigger input is connected and has no input.

Throws:

IllegalActionException - If checking the trigger for a token throws it or if the super class throws it.

_customTypeConstraints

protected java.util.Set<Inequality> _customTypeConstraints()

Set the input port greater than or equal to BaseType.GENERAL in case backward type inference is enabled and the input port has no type declared.

Overrides:

_customTypeConstraints in class TypedAtomicActor

Returns:

A set of inequalities.