package edu.vt.marian.search;

import java.util.*;
import java.io.*;

import edu.vt.marian.common.*;


/**
 * The sort of Sequencer that is used with large numbers of unweighted
 * links.  The keySet is a set of nodes on one side of links in the
 * class, and map is either LinkClassManager.sinkToSource() or
 * sourceToSinks().
 * <P>
 * This implementation simply extends MergeSequencer by defining the
 * addSets() method to invoke addSet() repeatedly for every WtdObjSet
 * created by mapping elements in the key set using the given mapping
 * function.
 *
 * @author Paul Mather
 * @author Robert France
 * @version $Id: FlatSetSequencer.java,v 1.2 2000/03/10 15:35:39 paul Exp $
 * @see MergeSequencer
 * @see Sequencer
 * @see WtdObjSetSequencer
 * @see java.util.Enumeration
 */

public class FlatSetSequencer extends MergeSequencer implements WtdObjSetSequencer
{
    /**
     * Create a merging sequencer for an unknown number of sets.
     */
    public FlatSetSequencer(long classSize, Debug d)
    {
	super( classSize, d );
    }


    /**
     * Add a new component set to the Sequencer with no scaling constant.
     *
     * @param keySet a weighted object set, each of .
     * @param map someone who can turn each FullID in keySet into a WtdObjSet.
     * @return ReturnCodes.OK --- set was added without problems;
     * anything else --- problems.
     */
    public int addSets(WtdObjSet keySet, WtdObjToSetMapping map)
    {
	WtdObjSetEnumeration enum;
	int returnValue;

	if (keySet != null && map != null)
	{
	    // Map every WtdObj in keySet to a WtdObjSet...
	    enum = keySet.elements();
	    while (enum.hasMoreElements())
	    {
		super.addSet( map.map( (WtdObj) enum.nextElement() ) );
	    }
	    returnValue = ReturnCodes.OK;
	}
	else
	    returnValue = ReturnCodes.BAD_PARAMS;

	return returnValue;
    }

}