WordRelation.java

/**
 * Portions Copyright 2001 Sun Microsystems, Inc.
 * Portions Copyright 1999-2001 Language Technologies Institute,
 * Carnegie Mellon University.
 * All Rights Reserved.  Use is subject to license terms.
 *
 * See the file "license.terms" for information on usage and
 * redistribution of this file, and for a DISCLAIMER OF ALL
 * WARRANTIES.
 */
package edu.cmu.sphinx.alignment.tokenizer;

import edu.cmu.sphinx.alignment.USEnglishTokenizer;

/**
 * Helper class to add words and breaks into a Relation object.
 */
public class WordRelation {

    private Relation relation;
    private USEnglishTokenizer tokenToWords;

    private WordRelation(Relation parentRelation, USEnglishTokenizer tokenToWords) {
        this.relation = parentRelation;
        this.tokenToWords = tokenToWords;
    }

    /**
     * Creates a WordRelation object with the given utterance and TokenToWords.
     *
     * @param utterance the Utterance from which to create a Relation
     * @param tokenToWords the TokenToWords object to use
     *
     * @return a WordRelation object
     */
    public static WordRelation createWordRelation(Utterance utterance,
            USEnglishTokenizer tokenToWords) {
        Relation relation = utterance.createRelation(Relation.WORD);
        return new WordRelation(relation, tokenToWords);
    }

    /**
     * Adds a break as a feature to the last item in the list.
     */
    public void addBreak() {
        Item wordItem = (Item) relation.getTail();
        if (wordItem != null) {
            FeatureSet featureSet = wordItem.getFeatures();
            featureSet.setString("break", "1");
        }
    }

    /**
     * Adds a word as an Item to this WordRelation object.
     *
     * @param word the word to add
     */
    public void addWord(String word) {
        Item tokenItem = tokenToWords.getTokenItem();
        Item wordItem = tokenItem.createDaughter();
        FeatureSet featureSet = wordItem.getFeatures();
        featureSet.setString("name", word);
        relation.appendItem(wordItem);
    }

    /**
     * Sets the last Item in this WordRelation to the given word.
     *
     * @param word the word to set
     */
    public void setLastWord(String word) {
        Item lastItem = relation.getTail();
        FeatureSet featureSet = lastItem.getFeatures();
        featureSet.setString("name", word);
    }

    /**
     * Returns the last item in this WordRelation.
     *
     * @return the last item
     */
    public Item getTail() {
        return relation.getTail();
    }
}