/* Copyright (C) 2002 Univ. of Massachusetts Amherst, Computer Science Dept.
This file is part of "MALLET" (MAchine Learning for LanguagE Toolkit).
http://www.cs.umass.edu/~mccallum/mallet
This software is provided under the terms of the Common Public License,
version 1.0, as published by http://www.opensource.org. For further
information, see the file `LICENSE' included with this distribution. */
/**
Tests membership of the token text in the provided list of phrases.
The lexicon words are provided in a file, one space-separated phrase per line.
@author Wei Lee and Andrew McCallum <a href="mailto:mccallum@cs.umass.edu">mccallum@cs.umass.edu</a>
Modifications by
@author Kedar Bellare <a href="mailto:kedarb@cs.umass.edu">kedarb@cs.umass.edu</a> for joint extraction.
*/
package cc.mallet.pipe.tsf;
import java.io.*;
import java.util.*;
import cc.mallet.pipe.*;
import cc.mallet.types.*;
public class TrieLexiconMembership extends Pipe implements Serializable {
// Perhaps give it your own tokenizer?
String name; // perhaps make this an array of names
boolean ignoreCase;
TrieLexicon lexicon;
public TrieLexiconMembership(String name, Reader lexiconReader,
boolean ignoreCase) {
this.name = name;
this.lexicon = new TrieLexicon(name, ignoreCase);
LineNumberReader reader = new LineNumberReader(lexiconReader);
String line;
while (true) {
try {
line = reader.readLine();
} catch (IOException e) {
throw new IllegalStateException();
}
if (line == null) {
break;
} else {
lexicon.add(line);
}
}
if (lexicon.size() == 0)
throw new IllegalArgumentException("Empty lexicon");
}
public TrieLexiconMembership(String name, Reader lexiconReader,
boolean ignoreCase, boolean includeDelims, String delim) {
this.name = name;
this.lexicon = new TrieLexicon(name, ignoreCase);
LineNumberReader reader = new LineNumberReader(lexiconReader);
String line;
while (true) {
try {
line = reader.readLine();
} catch (IOException e) {
throw new IllegalStateException();
}
if (line == null) {
break;
} else {
lexicon.add(line, includeDelims, delim);
}
}
if (lexicon.size() == 0)
throw new IllegalArgumentException("Empty lexicon");
}
public TrieLexiconMembership(String name, File lexiconFile,
boolean ignoreCase) throws FileNotFoundException {
this(name, new BufferedReader(new FileReader(lexiconFile)), ignoreCase);
}
public TrieLexiconMembership(String name, File lexiconFile,
boolean ignoreCase, boolean includeDelims, String delim)
throws FileNotFoundException {
this(name, new BufferedReader(new FileReader(lexiconFile)), ignoreCase,
includeDelims, delim);
}
public TrieLexiconMembership(File lexiconFile, boolean ignoreCase)
throws FileNotFoundException {
this(lexiconFile.getName(), lexiconFile, ignoreCase);
}
public TrieLexiconMembership(File lexiconFile) throws FileNotFoundException {
this(lexiconFile.getName(), lexiconFile, true);
}
public Instance pipe(Instance carrier) {
TokenSequence ts = (TokenSequence) carrier.getData();
lexicon.addFeatures(ts);
return carrier;
}
// Serialization
private static final long serialVersionUID = 1;
private static final int CURRENT_SERIAL_VERSION = 0;
private void writeObject(ObjectOutputStream out) throws IOException {
out.writeInt(CURRENT_SERIAL_VERSION);
out.writeObject(name);
out.writeObject(lexicon);
out.writeBoolean(ignoreCase);
}
private void readObject(ObjectInputStream in) throws IOException,
ClassNotFoundException {
int version = in.readInt();
this.name = (String) in.readObject();
this.lexicon = (TrieLexicon) in.readObject();
this.ignoreCase = in.readBoolean();
}
private static class TrieLexicon implements Serializable {
static final String END_OF_WORD_TOKEN = "end_of_word";
String name;
boolean ignoreCase;
Hashtable lex;
int size;
public TrieLexicon(String name, boolean ignoreCase) {
this.name = name;
this.ignoreCase = ignoreCase;
this.lex = new Hashtable();
this.size = 0;
}
public void add(String word) {
add(word, false, " ");
}
public void add(String word, boolean includeDelims, String delim) {
boolean newWord = false;
StringTokenizer st = new StringTokenizer(word, delim, includeDelims);
Hashtable currentLevel = lex;
while (st.hasMoreTokens()) {
String token = st.nextToken();
if (ignoreCase)
token = token.toLowerCase();
if (!currentLevel.containsKey(token)) {
currentLevel.put(token, new Hashtable());
newWord = true;
}
currentLevel = (Hashtable) currentLevel.get(token);
}
currentLevel.put(END_OF_WORD_TOKEN, "");
if (newWord)
size++;
}
public void addFeatures(TokenSequence ts) {
int i = 0;
while (i < ts.size()) {
int j = endOfWord(ts, i);
if (j == -1) {
i++;
} else {
for (; i <= j; i++) {
Token t = ts.get(i);
t.setFeatureValue(name, 1.0);
}
}
}
}
private int endOfWord(TokenSequence ts, int start) {
if (start < 0 || start >= ts.size()) {
System.err
.println("Lexicon.lastIndexOf: error - out of TokenSequence boundaries");
return -1;
}
Hashtable currentLevel = lex;
int end = -1;
for (int i = start; i < ts.size(); i++) {
Token t = ts.get(i);
String s = t.getText();
if (ignoreCase)
s = s.toLowerCase();
currentLevel = (Hashtable) currentLevel.get(s);
if (currentLevel == null) {
return end;
}
if (currentLevel.containsKey(END_OF_WORD_TOKEN)) {
end = i;
}
}
return end;
}
public int size() {
return size;
}
// Serialization
private static final long serialVersionUID = 1;
private static final int CURRENT_SERIAL_VERSION = 0;
private void writeObject(ObjectOutputStream out) throws IOException {
out.writeInt(CURRENT_SERIAL_VERSION);
out.writeObject(name);
out.writeObject(lex);
out.writeBoolean(ignoreCase);
out.writeInt(size);
}
private void readObject(ObjectInputStream in) throws IOException,
ClassNotFoundException {
int version = in.readInt();
this.name = (String) in.readObject();
this.lex = (Hashtable) in.readObject();
this.ignoreCase = in.readBoolean();
this.size = in.readInt();
}
}
}