classifieddatum.java

Standord Classifier实现了一个基于Java的最大熵分类器。用于模式识别

package edu.stanford.nlp.classify;

import edu.stanford.nlp.dbm.Datum;
import edu.stanford.nlp.process.Appliable;

/**
 * Stores a classified Datum with predicted and correct labels.
 */
public class ClassifiedDatum
{    
    private final Datum datum;    
    private final Object predictedLabel;    
    private final Object correctLabel;   
    private final boolean correct;
    
    /**
     * Constructs a new classification result for the given Datum with the given
     * predicted and correct labels.
     * @param datum Datum that was classified
     * @param predictedLabel label (class) predicted for this Datum by the Classifier
     * @param correctLabel correct label (class) to compare prediction to
     */
    public ClassifiedDatum(Datum datum,Object predictedLabel,Object correctLabel)
    {
        this.datum=datum;
        this.predictedLabel=predictedLabel;
        this.correctLabel=correctLabel;
        correct=predictedLabel.equals(correctLabel);
    }
    
    /**
     * Constructs a new classificationr esult for the given Datum with the given
     * predicted label, and using the datum's label as the correct label.
     * @param datum Data that was classified (containing correct label)
     * @param predictedLabel label (class) predicted for this Datum by the Classifier
     */
    public ClassifiedDatum(Datum datum,Object predictedLabel)
    {
        this(datum,predictedLabel,datum.label());
    }
    
    /** Returns the classified Datum. */
    public Datum getDatum() { return(datum); }
    /** Returns the label (class) predicted for the Datum by the Classifier. */
    public Object getPredictedLabel() { return(predictedLabel); }
    /** Returns the corect label (class) for the Datum. */
    public Object getCorrectLabel() { return(correctLabel); }
    /** Returns whether the predicted label matches the correct label. */
    public boolean isCorrect() { return(correct); }
    
    
    /** Appliable that returns the Datum inside a ClassifiedDatum. */
    public static Appliable datumExtractor() { return(datumExtractor); }
    
    /** Appliable that returns the Datum inside a ClassifiedDatum. */
    private static class DatumExtractor implements Appliable
    {
        public Object apply(Object o) { return(((ClassifiedDatum)o).getDatum()); }
    }
    
    private static final Appliable datumExtractor=new DatumExtractor();
}