ptolemy.actor.ptalon.lib
Class ReduceWorker

java.lang.Object
  ptolemy.kernel.util.NamedObj
      ptolemy.kernel.InstantiableNamedObj
          ptolemy.kernel.Entity
              ptolemy.kernel.ComponentEntity
                  ptolemy.actor.AtomicActor
                      ptolemy.actor.TypedAtomicActor
                          ptolemy.actor.ptalon.lib.ReduceWorker

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 ReduceWorker
extends TypedAtomicActor

A ReduceWorker actor, as a subsystem of the MapReduce system.

This actor has a parameter classNameForReduce which is the qualified name for a Java class that extends ptolemy.actor.ptalon.lib.MapReduceAlgorithm. It must also have a no argument constructor. By extending this abstract class, it will implement a method named reduce with type signature:

public List<String> reduce(String key, BlockingQueue<String> value)

This method defines the Reduce algorithm for the MapReduce system. At each call, it should return a list of Strings, which is a reduction of the list of input values. At each firing, this actor inputs all avaiable input keys and values. It outputs the value tokens when its doneReading port recieves a true value. This should only happen after all inputs have been sent to the system.

When implementing a custom reduce method in a subclass of MapReduceAlgorithm, note to use the take method to get values from the queue. Call the isQueueEmpty of MapReduceAlgorithm to test if this actor has stopped putting values on the queue and that all values have been taken from the queue. The last element of the queue will allways be the empty string. Ignore this value.

Since:

Ptolemy II 6.1

Version:

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

Author:

Adam Cataldo

See Also:

KeyValuePair, Serialized Form

Accepted Rating:

Red (cxh)

Proposed Rating:

Red (cxh)

Nested Class Summary

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

Entity.ContainedObjectsIterator

Field Summary

private boolean	_doneReading
private boolean	_readMode
private java.lang.Class<?>	_reduceClass
private java.util.Map<java.lang.String,MapReduceAlgorithm>	_runningAlgorithms Each key is a distinct key for a reduce call, and each value is a MapReduceAlgorithm to reduce a set of values.
StringParameter	classNameForReduce The qualifed class name for a Java class containing a method with signature: public static List<String[]> map(String key, String value) Each element of each returned list should be a length two array of Strings.
TypedIOPort	doneReading A boolean input.
TypedIOPort	inputKey A String input key.
TypedIOPort	inputValue A String input value.
TypedIOPort	outputKey A String output key.
TypedIOPort	outputValue A String output value.

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

ReduceWorker(CompositeEntity container, java.lang.String name)
Create a new actor in the specified container with the specified name.

Method Summary

private void	_setReduceMethod() Set the map method using the class specified in classNameForMap.
void	attributeChanged(Attribute attribute) React to a change in an attribute.
void	fire() Read in a token on the inputKey and inputValue ports and output pairs of tokens on the ouputKey, outputValue ports.
void	initialize() Extract the map method from the classNameForMap parameter.
boolean	postfire() Return true, unless stop() has been called, in which case, return false.
boolean	prefire() Return true if there is an available key token and value token on the inputKey and inputValue ports.
void	wrapup() Clean up memory.

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, 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

_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, 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

Methods inherited from interface ptolemy.kernel.util.Derivable

getDerivedLevel, getDerivedList, propagateValue

Field Detail

classNameForReduce

public StringParameter classNameForReduce

The qualifed class name for a Java class containing a method with signature:

public static List<String[]> map(String key, String value)

Each element of each returned list should be a length two array of Strings.

doneReading

public TypedIOPort doneReading

A boolean input. When this input is true, the actor is done reading values, and it may output tokens for each key it recieved.

inputKey

public TypedIOPort inputKey

A String input key.

inputValue

public TypedIOPort inputValue

A String input value.

outputKey

public TypedIOPort outputKey

A String output key.

outputValue

public TypedIOPort outputValue

A String output value.

_doneReading

private boolean _doneReading

_readMode

private boolean _readMode

_reduceClass

private java.lang.Class<?> _reduceClass

_runningAlgorithms

private java.util.Map<java.lang.String,MapReduceAlgorithm> _runningAlgorithms

Each key is a distinct key for a reduce call, and each value is a MapReduceAlgorithm to reduce a set of values.

Constructor Detail

ReduceWorker

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

Create a new 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 container.

name - The name of this actor within the container.

Throws:

IllegalActionException - If this actor cannot be contained by the proposed container (see the setContainer() method).

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

Method Detail

attributeChanged

public void attributeChanged(Attribute attribute)
                      throws IllegalActionException

React to a change in an attribute. This method is called by a contained attribute when its value changes. In this base class, the method does nothing. In derived classes, this method may throw an exception, indicating that the new attribute value is invalid. It is up to the caller to restore the attribute to a valid value if an exception is thrown. If the attribute changed is classNameForReduce, update this actor accordingly.

Overrides:

attributeChanged in class NamedObj

Parameters:

attribute - The attribute that changed.

Throws:

IllegalActionException - If the change is not acceptable to this container. If the class set in classNameForReduce does not exist, or if the class exists but does not contain a map method with an appropriate signature, this exception will be thrown.

fire

public void fire()
          throws IllegalActionException

Read in a token on the inputKey and inputValue ports and output pairs of tokens on the ouputKey, outputValue ports.

Specified by:

fire in interface Executable

Overrides:

fire in class AtomicActor

Throws:

IllegalActionException - If there is any trouble calling the map method.

prefire

public boolean prefire()
                throws IllegalActionException

Return true if there is an available key token and value token on the inputKey and inputValue ports.

Specified by:

prefire in interface Executable

Overrides:

prefire in class AtomicActor

Returns:

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

Throws:

IllegalActionException - Not thrown in this class.

postfire

public boolean postfire()
                 throws IllegalActionException

Description copied from class: AtomicActor

Return true, unless stop() has been called, in which case, return false. Derived classes override this method to define operations to be performed at the end of every iteration of its execution, after one invocation of the prefire() method and any number of invocations of the fire() method. This method typically wraps up an iteration, which may involve updating local state. In derived classes, this method returns false to indicate that this actor should not be fired again.

Specified by:

postfire in interface Executable

Overrides:

postfire in class AtomicActor

Returns:

The base class return value.

Throws:

IllegalActionException - If thrown in the base class.

wrapup

public void wrapup()
            throws IllegalActionException

Clean up memory.

Specified by:

wrapup in interface Initializable

Overrides:

wrapup in class AtomicActor

Throws:

IllegalActionException - If thrown in the base class.

initialize

public void initialize()
                throws IllegalActionException

Extract the map method from the classNameForMap parameter.

Specified by:

initialize in interface Initializable

Overrides:

initialize in class AtomicActor

Throws:

IllegalActionException - If unable to extract an appropriate map method.

_setReduceMethod

private void _setReduceMethod()
                       throws IllegalActionException

Set the map method using the class specified in classNameForMap.

Throws:

IllegalActionException - If the map method does not exist, has the wrong type signature, or has the wrong access modifiers.