package edu.stanford.nlp.ling;
/**
* A {@code Word} object acts as a Label by containing a String.
* This class is in essence identical to a {@code StringLabel}, but
* it also uses the value to implement the {@code HasWord} interface.
*
* @author Christopher Manning
* @version 2000/12/20
*/
public class Word extends StringLabel implements HasWord {
/**
* String representation of an empty.
*/
private static final String EMPTY_STRING = "*t*";
/**
* Word representation of an empty.
*/
public static final Word EMPTY = new Word(EMPTY_STRING);
/**
* Construct a new word with a {@code null} value.
*/
public Word() {
super();
}
/**
* Construct a new word, with the given value.
*
* @param word String value of the Word
*/
public Word(String word) {
super(word);
}
/**
* Construct a new word, with the given value.
*
* @param word String value of the Word
*/
public Word(String word, int beginPosition, int endPosition) {
super(word, beginPosition, endPosition);
}
/**
* Creates a new word whose word value is the value of any
* class that supports the {@code Label} interface.
*
* @param lab The label to be used as the basis of the new Word
*/
public Word(Label lab) {
super(lab);
}
@Override
public String word() {
return value();
}
@Override
public void setWord(String word) {
setValue(word);
}
// extra class guarantees correct lazy loading (Bloch p.194)
private static class WordFactoryHolder {
private static final LabelFactory lf = new WordFactory();
private WordFactoryHolder() { }
}
/**
* Return a factory for this kind of label (i.e., {@code Word}).
* The factory returned is always the same one (a singleton).
*
* @return The label factory
*/
@Override
public LabelFactory labelFactory() {
return WordFactoryHolder.lf;
}
/**
* Return a factory for this kind of label.
*
* @return The label factory
*/
public static LabelFactory factory() {
return WordFactoryHolder.lf;
}
private static final long serialVersionUID = -4817252915997034058L;
}