/* 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.decoder.ff.tm;

import java.util.List;

import joshua.decoder.ff.FeatureFunction;


/**
 * Represents a set of rules under a particular TrieGrammar node.
 * Therefore, all the rules under a RuleCollection will share:
 *
 * <ul>
 *   <li>arity</li>
 *   <li>source side</li>
 * </ul>
 * 
 * @author Zhifei Li
 * @author Lane Schwartz
 * @version $LastChangedDate: 2010-02-10 09:59:38 -0600 (Wed, 10 Feb 2010) $
 */
public interface RuleCollection {

	/**
	 * Sorts the grammar rules in this collection using the
	 * provided feature functions.
	 * 
	 * @param l_models Feature function models to use during sorting.
	 */
	void sortRules(List<FeatureFunction> l_models);
	
	/**
	 * TODO: now, we assume this function will be called only
	 * after all the rules have been read; this method need to
	 * be synchronized as we will call this function only after
	 * the decoding begins to avoid the synchronized method,
	 * we should call this once the grammar is finished
	 * <p>
	 * public synchronized ArrayList<Rule> get_sorted_rules(){
	 * l_models: if it is non-null, then the rules will be
	 * sorted using the new feature functions (or new weight),
	 * otherwise, just return a sorted list based on the last
	 * time of feature functions
     * <p>
     * Only CubePruning requires that rules are sorted based on
     * est_cost (confirmed by zhifei)
	 */
	List<Rule> getSortedRules();
	
	
	/**get the list of rules (which may not be sorted or not)
	 * */
	List<Rule> getRules();
	
	
	/**
	 * Gets the source side for all rules in this RuleCollection.
	 * This source side is the same for all the rules in the
	 * RuleCollection.
	 * 
	 * @return the (common) source side for all rules in this
	 *         RuleCollection
	 */
	int[] getSourceSide();
	
	/**
	 * Gets the number of nonterminals in the source side of
	 * the rules in this RuleCollection. The source side is the
	 * same for all the rules in the RuleCollection, so the
	 * arity will also be the same for all of these rules.
	 * 
	 * @return the (common) number of nonterminals in 
	 *         the source side of the rules in this RuleCollection
	 */
	int getArity();
	
}