org.debellor.weka
Class WekaClassifier

java.lang.Object
  org.debellor.core.Cell
      org.debellor.weka.WekaClassifier

public class WekaClassifier
extends Cell

Debellor wrapper for Weka classifiers - subclasses of weka.classifiers.Classifier. Weka class implementing the classifier is identified by its name given in long (with package specification) or short form. This name must exactly match (including case) the corresponding Weka class name. Available names can be found by running Weka GUI (Explorer or Experimenter) and opening the selection list of classifiers. Alternatively, you can browse Weka code (subpackages of weka.classifiers package).

Parameters (or options in Weka's terminology) can be passed to Weka classifier in a standard Debellor's way, by calling Cell.set(java.lang.String, java.lang.String) or Cell.setParameters(org.debellor.core.Parameters). Parameters should have names of corresponding Weka options, exactly in the same form as is printed in Weka GUI in the dialog for setting classifier options.

For example, the "J48" classifier, which implements C4.5 decision tree, has options "binarySplits", "confidenceFactor", "debug", ... You can set their values in the following way:

 Cell learner = new WekaClassifier("J48");
 learner.set("binarySplits", "true");
 learner.set("confidenceFactor", "0.45");
 

If you don't specify some option, its default value will be used.

Author:

Marcin Wojnarski

Nested Class Summary

Nested classes/interfaces inherited from class org.debellor.core.Cell

Cell.CellMethod, Cell.State, Cell.Stream

Field Summary

protected Cell.Stream

input

Fields inherited from class org.debellor.core.Cell

parameters, random

Constructor Summary

WekaClassifier(java.lang.Class<? extends weka.classifiers.Classifier> learnerClass)

WekaClassifier(java.lang.String className)

Method Summary

protected void	onClose() Called by Cell.Stream.close().
protected void	onErase() Called by Cell.erase().
protected void	onLearn() Learning procedure of the cell.
protected Sample	onNext() Called by Cell.Stream.next().
protected Sample.SampleType	onOpen() Called by Cell.open().
java.lang.String	toString()

Methods inherited from class org.debellor.core.Cell

close, erase, getAvailableParams, getParameters, learn, newThread, newThread, next, open, openInputStream, set, set, set, set, setAvailableParams, setParameters, setRandomSeed, setSource, state

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

input

protected Cell.Stream input

Constructor Detail

WekaClassifier

public WekaClassifier(java.lang.Class<? extends weka.classifiers.Classifier> learnerClass)
               throws java.lang.Exception

Throws:

java.lang.Exception

WekaClassifier

public WekaClassifier(java.lang.String className)
               throws java.lang.Exception

Parameters:

className - Name of Weka class implementing the classifier algorithm, given in long (with package specification) or short form.

Throws:

java.lang.Exception

Method Detail

onLearn

protected void onLearn()
                throws java.lang.Exception

Description copied from class: Cell

Learning procedure of the cell. For example, may train the internal decision model; read and buffer input data; calculate an evaluation measure of another cell; calculate data-driven parameters of a preprocessing algorithm (e.g. attribute means for normalization algorithm) etc. Called by Cell.learn().

Must be overridden in all subclasses that implement trainable cells. If your cell is not trainable, you must provide this information to the Cell base class by calling Cell.Cell(boolean) instead of Cell.Cell() in your constructor. Overriders may safely assume that the cell is in Cell.State.EMPTY state when onLearn is called - this is guaranteed by implementation of learn().

Overrides:

onLearn in class Cell

Throws:

java.lang.Exception

onErase

protected void onErase()
                throws DebellorException

Description copied from class: Cell

Called by Cell.erase(). Performs the actual erasure of cell content, while erase checks only against access violation and handles exceptions. Must be overridden in subclasses if erasure is to be used. Overriders may assume that the cell is in Cell.State.CLOSED state.

Overrides:

onErase in class Cell

Throws:

DebellorException

onOpen

protected Sample.SampleType onOpen()
                            throws java.lang.Exception

Description copied from class: Cell

Called by Cell.open(). Performs the actual opening of communication session, while open checks only against access violation and handles exceptions. Must be overridden in subclasses if open is to be used. Overriders may assume that the cell is in Cell.State.CLOSED state.

Overrides:

onOpen in class Cell

Throws:

java.lang.Exception

onNext

protected Sample onNext()
                 throws java.lang.Exception

Description copied from class: Cell

Called by Cell.Stream.next(). Performs the actual generation of the next output sample, while Stream.next() checks only against access violation and handles exceptions. Must be overridden in the subclass if next is to be used, i.e. if the subclass should generate some output data. Overriders may assume that the cell is in Cell.State.OPEN state.

Overrides:

onNext in class Cell

Throws:

java.lang.Exception

onClose

protected void onClose()
                throws java.lang.Exception

Description copied from class: Cell

Called by Cell.Stream.close(). Performs the actual closing of communication session, while close checks only against access violation and handles exceptions. Must be overridden in subclasses if close is to be used. Usually the overrider will use onClose to release resources, to let them be garbage-collected. Overriders may assume that the cell is in Cell.State.OPEN state.

Overrides:

onClose in class Cell

Throws:

java.lang.Exception

toString

public java.lang.String toString()

Overrides:

toString in class Cell