org.jactr.core.chunk.ChunkActivationComparator.java Source code

Introduction

Here is the source code for org.jactr.core.chunk.ChunkActivationComparator.java

Source

/**
 * Copyright (C) 2001-3, Anthony Harrison anh23@pitt.edu This library 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 org.jactr.core.chunk;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.jactr.core.chunk.five.ISubsymbolicChunk5;
import org.jactr.core.production.request.ChunkTypeRequest;

/*
 * sorts descending based on current activation
 */
/*
 * sorts by activation, descending
 */
/**
 * Description of the Class
 * 
 * @author harrison
 * @created April 18, 2003
 */
public class ChunkActivationComparator implements java.util.Comparator<IChunk> {

    /**
     * Logger definition
     */

    static private final transient Log LOGGER = LogFactory.getLog(ChunkActivationComparator.class);

    ChunkTypeRequest _pattern;

    /*
     * 1 one <two 0 one=two -1 one>two
     */
    /**
     * Description of the Method
     * 
     * @param one
     *            Description of the Parameter
     * @param two
     *            Description of the Parameter
     * @return Description of the Return Value
     */
    public int compare(IChunk one, IChunk two) {
        /*
         * exact same chunk
         */
        if (one == two || (one != null && one.equals(two)))
            return 0;

        ISubsymbolicChunk sc1 = one.getSubsymbolicChunk();
        ISubsymbolicChunk sc2 = two.getSubsymbolicChunk();

        double base1 = sc1.getActivation();
        double base2 = sc2.getActivation();

        if (_pattern != null)
            try {
                base1 = ((ISubsymbolicChunk5) sc1).getActivation(_pattern);
                base2 = ((ISubsymbolicChunk5) sc2).getActivation(_pattern);
            } catch (ClassCastException cce) {
                if (LOGGER.isDebugEnabled())
                    LOGGER.debug("Someone isnt a subsymbolicchunk5");
            }
        // System.out.println(one+": "+base1+" <=> "+two+": "+base2);

        /*
         * this will eliminate chunks of the same activation, but possibly different
         * chunks - dumb mistake
         */
        // if (base1 == base2)
        // {
        // return 0;
        // }
        // else
        if (base1 < base2)
            return 1;
        if (base1 == base2) /*
                             * this is necessary because this comparator is often
                             * used in a set situation
                             * 
                             * @see DefaultSlotSearchSupport.findCandidates(). If we
                             *      just return -1 all the time when the activations
                             *      are equal, then searching for a specific chunk
                             *      in the set might abort early. This was the case
                             *      when candidateList.removeAll(cullSet) was being
                             *      called in findCandidates and cullSet was not
                             *      actually removed.
                             */
            // sort by something deterministic - name..
            return one.getSymbolicChunk().getName().compareTo(two.getSymbolicChunk().getName());
        return -1;
    }

    /**
     * Sets the pattern attribute of the IChunkActivationComparator object
     * 
     * @param p
     *            The new pattern value
     */
    public void setChunkTypeRequest(ChunkTypeRequest p) {
        _pattern = p;
    }

}