Tokenization.java

/* 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:mccallum@cs.umass.edu">mccallum@cs.umass.edu</a>
 */

package edu.nd.nina.extract;

import edu.nd.nina.types.Sequence;

public interface Tokenization extends Sequence {
	/**
	 * Returns the document of which this is a tokenization.
	 */
	public Object getDocument();

	public Span getSpan(int i);

	/**
	 * Returns a span formed by concatenating the spans from start to end. In
	 * more detail:
	 * <ul>
	 * <li>The start of the new span will be the start index of
	 * <tt>getSpan(start)</tt>.
	 * <li>The end of the new span will be the start index of
	 * <tt>getSpan(end)</tt>.
	 * <li>Unless <tt>start == end</tt>, the new span will completely include
	 * <tt>getSpan(start)</tt>.
	 * <li>The new span will never intersect <tt>getSpan(end)</tt>
	 * <li>If <tt>start == end</tt>, then the new span contains no text.
	 * </ul>
	 * 
	 * @param start
	 *            The index of the first token in the new span (inclusive). This
	 *            is an index of a token, *not* an index into the document.
	 * @param end
	 *            The index of the first token in the new span (exclusive). This
	 *            is an index of a token, *not* an index into the document.
	 * @return A span into this tokenization's document
	 */
	Span subspan(int start, int end);
}