token.java

来自「mallet是自然语言处理、机器学习领域的一个开源项目。」· Java 代码 · 共 154 行

/* 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. */




/** 
   @author Andrew McCallum <a href="mailto:[e-mail]">[e-mail]</a>
 */

package edu.umass.cs.mallet.base.types;

import edu.umass.cs.mallet.base.util.PropertyList;
import java.util.Iterator;
import java.util.ArrayList;
import java.util.HashMap;
import java.io.ObjectOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.Serializable;

/** A representation of a piece of text, usually a single word, to
		which we can attach properties. */

public class Token implements Serializable, PropertyHolder
{

	private String text;
	PropertyList properties = null;				// for arbitrary properties
	PropertyList features = null;					// numeric, to turn into a FeatureVector
	
	public Token (String s)
	{
		text = s.intern();
	}

	public String getText ()
	{
		return text;
	}

	public void setText (String t)
	{
		text = t.intern();
	}

	// xxx This implementation may change in the future!
	// If you really just want the text, you should use Token.getText() instead.
	public String toString ()
	{
		StringBuffer sb = new StringBuffer ();
		sb.append (getText());
		if (features != null) {
			PropertyList.Iterator iter = features.iterator();
			while (iter.hasNext()) {
				iter.next();
				sb.append (" feature(" + iter.getKey() + ")=" +iter.getNumericValue());
			}
		}
		if (properties != null) {
			PropertyList.Iterator iter = properties.iterator();
			while (iter.hasNext()) {
				iter.next();
				if (iter.isNumeric())
					sb.append (" property(" + iter.getKey() + ")=" +iter.getNumericValue());
				else
					sb.append (" property(" + iter.getKey() + ")=" +iter.getObjectValue());
			}
		}
		return sb.toString();
	}

	public FeatureVector toFeatureVector (Alphabet dict, boolean binary)
	{
		return new FeatureVector (dict, features, binary);
	}

	public void setProperty (String key, Object value)
	{
		properties = PropertyList.add (key, value, properties);
	}

	public void setNumericProperty (String key, double value)
	{
		properties = PropertyList.add (key, value, properties);
	}

	public PropertyList getProperties ()
	{
		return properties;
	}

	public void setProperties (PropertyList newProperties)
	{
		properties = newProperties;
	}

	public Object getProperty (String key)
	{
		return properties == null ? null : properties.lookupObject (key);
	}

	public double getNumericProperty (String key)
	{
		return (properties == null ? 0.0 : properties.lookupNumber (key));
	}

	public boolean hasProperty (String key)
	{
		return (properties != null && properties.hasProperty( key ));
	}

	public void setFeatureValue (String key, double value)
	{
		features = PropertyList.add (key, value, features);
	}

	public double getFeatureValue (String key)
	{
		return (features == null ? 0.0 : features.lookupNumber (key));
	}

	public PropertyList getFeatures ()
	{
		return features;
	}

	public void setFeatures (PropertyList pl)
	{
		features = pl;
	}

  // 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.defaultWriteObject ();
  }

  private void readObject (ObjectInputStream in) throws IOException, ClassNotFoundException {
    int version = in.readInt ();
    in.defaultReadObject ();
  }


}