/* 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
 */
/*
 * This file is based on the edu.umd.clip.mt.Phrase class from the
 * University of Maryland's umd-hadoop-mt-0.01 project. That project
 * is released under the terms of the Apache License 2.0, but with
 * special permission for the Joshua Machine Translation System to
 * release modifications under the LGPL version 2.1. LGPL version
 * 3 requires no special permission since it is compatible with
 * Apache License 2.0
 */
package joshua.corpus;

import java.util.ArrayList;

import joshua.corpus.vocab.SymbolTable;
import joshua.corpus.vocab.Vocabulary;



/**
 * The simplest concrete implementation of Phrase.
 *
 * @author wren ng thornton <wren@users.sourceforge.net>
 * @version $LastChangedDate: 2009-09-04 15:09:50 -0500 (Fri, 04 Sep 2009) $
 */
public class BasicPhrase extends AbstractPhrase {
	private byte       language;
	private SymbolTable vocabulary;
	private int[]      words;
	
	
	public BasicPhrase(byte language, String sentence) {
		this.language   = language;
		this.vocabulary = new Vocabulary();
		this.words = splitSentence(sentence, vocabulary);
	}
	
	/** Note that the Vocabulary is shared, not cloned. */
	public BasicPhrase(byte language, String sentence, Vocabulary vocabulary) {
		this.language   = language;
		this.vocabulary = vocabulary;
		this.words = splitSentence(sentence, vocabulary);
	}
	
	
	private BasicPhrase() {}
	
	public int[] getWordIDs()  {
		return words;
	}
	
	/* See Javadoc for Phrase interface. */
	public BasicPhrase subPhrase(int start, int end) {
		BasicPhrase that = new BasicPhrase();
		that.language    = this.language;
		that.vocabulary  = this.vocabulary;
		that.words       = new int[end-start+1];
		System.arraycopy(this.words, start, that.words, 0, end-start+1);
		return that;
	}
	
	/* See Javadoc for Phrase interface. */
	public ArrayList<Phrase> getSubPhrases() {
		return this.getSubPhrases(this.size());
	}
	
	/* See Javadoc for Phrase interface. */
	public ArrayList<Phrase> getSubPhrases(int maxLength) {
		ArrayList<Phrase> phrases = new ArrayList<Phrase>();
		int len = this.size();
		for (int n = 1; n <= maxLength; n++)
			for (int i = 0; i <= len-n; i++)
				phrases.add(this.subPhrase(i, i + n - 1));
		return phrases;
	}
	
	/* See Javadoc for Phrase interface. */
	public int size() { return (words == null ? 0 : words.length); }
	
	/* See Javadoc for Phrase interface. */
	public int getWordID(int position) { return words[position]; }
	
	/* See Javadoc for Phrase interface. */
	public SymbolTable getVocab()       { return vocabulary; }
	
	/**
	 * Returns a human-readable String representation of the
	 * phrase.
	 * <p>
	 * The implementation of this method is slightly more
	 * efficient than that inherited from <code>AbstractPhrase</code>.
	 * 
	 * @return a human-readable String representation of the
	 *         phrase.
	 */
	public String toString() {
		StringBuffer sb = new StringBuffer();
		if (words != null) {
			for (int i = 0; i < words.length; ++i) {
				if (i != 0) sb.append(' ');
				sb.append(vocabulary.getWord(words[i]));
			}
		}
		return sb.toString();
	}
}