Package ptolemy.actor.ptalon.lib

Class MapWorker

  • All Implemented Interfaces:
    java.lang.Cloneable, Actor, Executable, FiringsRecordable, Initializable, TypedActor, Changeable, Debuggable, DebugListener, Derivable, Instantiable, ModelErrorHandler, MoMLExportable, Moveable, Nameable
    public class MapWorker
extends TypedAtomicActor
    A MapWorker actor, as a subsystem of the MapReduce system.

    This actor has a parameter classNameForMap 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 map with type signature:

    public List<KeyValuePair> map(String key, String value)

    This method defines the Map algorithm for the MapReduce system. At each call, it should return list of KeyValuePairs, which is just a pair of strings, one representing a key for the reduce algorithm, and one representing a value for the reduce algorithm. One instance of the MapReduce algorithm class will be created when the classNameForMap parameter is set. It will be reused at each firing. This actor inputs a key and value token and outputs key, value pairs for each pair in the list generated by the user defined map procedure.

    Since:
    Ptolemy II 6.1
    Version:
    $Id$
    Author:
    Adam Cataldo, Adam Cataldo
    See Also:
    KeyValuePair, MapReduceAlgorithm
    Pt.AcceptedRating:
    Red (cxh)
    Pt.ProposedRating:
    Red (cxh)

    • Field Detail

      • classNameForMap

        public StringParameter classNameForMap
        The qualified 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.

      • inputKey

        public TypedIOPort inputKey
        A String input key.

      • inputValue

        public TypedIOPort inputValue
        A String input value.

      • outputKey

        public TypedIOPort outputKey
        A String output key. For each pair of inputKey, inputValue tokens read in, a possibly empty list of outputKey, outputValue pairs will be outputs.

      • outputValue

        public TypedIOPort outputValue
        A String output value. For each pair of inputKey, inputValue tokens read in, a possibly empty list of outputKey, outputValue pairs will be outputs.

    • Constructor Detail

      • MapWorker

        public MapWorker​(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 classNameForMap, 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 classNameForMap does not exist, or if the class exists but does not contain a map method with an appropriate signature, this exception will be thrown.