/*
* Copyright 1999-2002 Carnegie Mellon University.
* Portions Copyright 2002 Sun Microsystems, Inc.
* Portions Copyright 2002 Mitsubishi Electric Research Laboratories.
* 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.linguist.language.grammar;
import edu.cmu.sphinx.util.ExtendedStreamTokenizer;
import edu.cmu.sphinx.util.LogMath;
import edu.cmu.sphinx.util.props.*;
import java.io.IOException;
import java.util.*;
/**
* Defines a grammar based upon a list of words in a file. The format of the file is just one word per line. For
* example, for an isolated digits grammar the file will simply look like:
* <pre>
* zero
* one
* two
* three
* four
* five
* six
* seven
* eight
* nine
* </pre>
* The path to the file is defined by the {@link #PROP_PATH PROP_PATH} property. If the {@link #PROP_LOOP PROP_LOOP}
* property is true, the grammar created will be a looping grammar. Using the above digits grammar example, setting
* PROP_LOOP to true will make it a connected-digits grammar.
* <p/>
* All probabilities are maintained in LogMath log base.
*/
public class SimpleWordListGrammar extends Grammar implements Configurable {
/** The property that defines the location of the word list grammar */
@S4String(defaultValue = "spelling.gram")
public final static String PROP_PATH = "path";
/** The property that if true, indicates that this is a looping grammar */
@S4Boolean(defaultValue = true)
public final static String PROP_LOOP = "isLooping";
// ---------------------
// Configurable data
// ---------------------
private String path;
private boolean isLooping;
private LogMath logMath;
public SimpleWordListGrammar(String path, boolean isLooping, boolean showGrammar, boolean optimizeGrammar, boolean addSilenceWords, boolean addFillerWords, edu.cmu.sphinx.linguist.dictionary.Dictionary dictionary) {
super(showGrammar,optimizeGrammar,addSilenceWords,addFillerWords,dictionary);
this.path = path;
this.isLooping = isLooping;
logMath = LogMath.getLogMath();
}
public SimpleWordListGrammar() {
}
/*
* (non-Javadoc)
*
* @see edu.cmu.sphinx.util.props.Configurable#newProperties(edu.cmu.sphinx.util.props.PropertySheet)
*/
@Override
public void newProperties(PropertySheet ps) throws PropertyException {
super.newProperties(ps);
path = ps.getString(PROP_PATH);
isLooping = ps.getBoolean(PROP_LOOP);
}
/**
* Create class from reference text (not implemented).
*
* @param bogusText dummy variable
*/
@Override
protected GrammarNode createGrammar(String bogusText)
throws NoSuchMethodException {
throw new NoSuchMethodException("Does not create "
+ "grammar with reference text");
}
/** Creates the grammar. */
@Override
protected GrammarNode createGrammar() throws IOException {
ExtendedStreamTokenizer tok = new ExtendedStreamTokenizer(path, true);
GrammarNode initialNode = createGrammarNode("<sil>");
GrammarNode branchNode = createGrammarNode(false);
GrammarNode finalNode = createGrammarNode("<sil>");
finalNode.setFinalNode(true);
List<GrammarNode> wordGrammarNodes = new LinkedList<GrammarNode>();
while (!tok.isEOF()) {
String word;
while ((word = tok.getString()) != null) {
word = word.toLowerCase();
GrammarNode wordNode = createGrammarNode(word);
wordGrammarNodes.add(wordNode);
}
}
// now connect all the GrammarNodes together
initialNode.add(branchNode, LogMath.LOG_ONE);
float branchScore = logMath.linearToLog(
1.0 / wordGrammarNodes.size());
for (GrammarNode wordNode : wordGrammarNodes) {
branchNode.add(wordNode, branchScore);
wordNode.add(finalNode, LogMath.LOG_ONE);
if (isLooping) {
wordNode.add(branchNode, LogMath.LOG_ONE);
}
}
return initialNode;
}
}