/* This file is part of the Joshua Machine Translation System.
 * 
 * Joshua is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1
 * of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free
 * Software Foundation, Inc., 59 Temple Place, Suite 330, Boston,
 * MA 02111-1307 USA
 */
package joshua.corpus;


import java.util.*;

import joshua.corpus.vocab.SymbolTable;


/**
 * ContiguousPhrase implements the Phrase interface by linking into
 * indices within a corpus. This is intended to be a very low-memory
 * implementation of the class.
 *
 * @author Chris Callison-Burch
 * @since  29 May 2008
 * @version $LastChangedDate:2008-09-18 12:47:23 -0500 (Thu, 18 Sep 2008) $
 */
public class ContiguousPhrase extends AbstractPhrase {

//===============================================================
// Constants
//===============================================================
	
//===============================================================
// Member variables
//===============================================================

	protected int startIndex;
	protected int endIndex;
	protected Corpus corpusArray;
 
//===============================================================
// Constructor(s)
//===============================================================
	
	public ContiguousPhrase(int startIndex, int endIndex, Corpus corpusArray) {
		this.startIndex  = startIndex;
		this.endIndex    = endIndex;
		this.corpusArray = corpusArray;
	}
	

//===============================================================
// Public
//===============================================================
	
	//===========================================================
	// Accessor methods (set/get)
	//===========================================================
	
	/**
	 * @return the vocabulary that the words in this phrase are
	 *         drawn from.
	 */
	public SymbolTable getVocab() {
		return corpusArray.getVocabulary();
	}
	
	
	/**
	 * This method copies the phrase into an array of ints.
	 * This method should be avoided if possible.
	 * 
	 * @return an int[] corresponding to the ID of each word
	 *         in the phrase
	 */
	public int[] getWordIDs() {
		int[] words = new int[endIndex-startIndex];
		for (int i = startIndex; i < endIndex; i++) {
			words[i-startIndex] = corpusArray.getWordID(i); //corpusArray.corpus[i];
		}
		return words;
	}
	
	
	public int getWordID(int position) {
		return corpusArray.getWordID(startIndex+position);
//		return corpusArray.corpus[startIndex+position];
	}
	
	
	public int size() {
		return endIndex-startIndex;
	}
	
	
	//===========================================================
	// Methods
	//===========================================================
	
	
	/**
	 * Gets all possible subphrases of this phrase, up to and
	 * including the phrase itself. For example, the phrase "I
	 * like cheese ." would return the following:
	 * <ul>
	 * <li>I
	 * <li>like
	 * <li>cheese
	 * <li>.
	 * <li>I like
	 * <li>like cheese
	 * <li>cheese .
	 * <li>I like cheese
	 * <li>like cheese .
	 * <li>I like cheese .
	 * </ul>
	 * 
	 * @return ArrayList of all possible subphrases.
	 */
	public List<Phrase> getSubPhrases() {
		return getSubPhrases(size());
	}
	
	
	/**
	 * Returns a list of subphrases only of length
	 * <code>maxLength</code> or smaller.
	 * 
	 * @param maxLength the maximum length phrase to return.
	 * @return ArrayList of all possible subphrases of length
	 *         maxLength or less
	 * @see #getSubPhrases()
	 */
	public List<Phrase> getSubPhrases(int maxLength) {
		if (maxLength > size()) return getSubPhrases(size());
		List<Phrase> phrases=new ArrayList<Phrase>();
		for (int i = 0; i < size(); i++) {
			for (int j=i+1; (j <= size()) && (j-i <= maxLength); j++) {
				Phrase subPhrase = subPhrase(i,j);
				phrases.add(subPhrase);
			}
		}
		return phrases;
	}
	
	
	/**
	 * creates a new phrase object from the indexes provided.
	 * <P>
	 * NOTE: subList merely creates a "view" of the existing
	 * Phrase object. Memory taken up by other Words in the
	 * Phrase is not freed since the underlying subList object
	 * still points to the complete Phrase List.
	 *
	 * @see ArrayList#subList(int, int)
	 */
	public Phrase subPhrase(int start, int end) {
		return new ContiguousPhrase(startIndex+start, startIndex+end, corpusArray);
	}
	
	
//===============================================================
// Protected 
//===============================================================
	
	//===============================================================
	// Methods
	//===============================================================


//===============================================================
// Private 
//===============================================================
	
	//===============================================================
	// Methods
	//===============================================================
	
	
//===============================================================
// Static
//===============================================================


//===============================================================
// Main 
//===============================================================

	/**
	 * Main contains test code
	 */
	public static void main(String[] args) {
		
	}
}