/* 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. */
/**
If the new article contains a "header", like "SOCCER-", or "RUGBY LEAGUE-",
add an indicative feature to all Tokens.
@author Andrew McCallum <a href="mailto:mccallum@cs.umass.edu">mccallum@cs.umass.edu</a>
*/
package cc.mallet.share.mccallum.ner;
import java.io.*;
import cc.mallet.pipe.*;
import cc.mallet.types.Instance;
import cc.mallet.types.Token;
import cc.mallet.types.TokenSequence;
public class TokenSequenceDocHeader extends Pipe implements Serializable
{
public Instance pipe (Instance carrier)
{
TokenSequence ts = (TokenSequence) carrier.getData();
if (ts.size() > 3
&& (ts.get(2).getText().equals("-") || ts.get(3).getText().equals("-"))
&& ts.get(1).getText().matches("[A-Z]+")) {
String header = ts.get(1).getText();
if (header.equals("PRESS")) // Don't bother with "PRESS DIGEST" headers
return carrier;
String featureName = "HEADER="+header;
for (int i = 0; i < ts.size(); i++) {
Token t = ts.get(i);
// Only apply this feature to capitalized words, because if we apply it to everything
// we easily get an immense number of possible feature conjunctions, (e.g. every word
// with each of these HEADER= features.
if (t.getText().matches("^[A-Z].*"))
t.setFeatureValue (featureName, 1.0);
}
}
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);
}
private void readObject (ObjectInputStream in) throws IOException, ClassNotFoundException {
int version = in.readInt ();
}
}