functionmatchpart.java

High performance DB query

/*
 * @(#)$Id: FunctionMatchpart.java,v 1.3 2005/03/07 22:17:32 huebsch Exp $
 *
 * Copyright (c) 2001-2004 Regents of the University of California.
 * All rights reserved.
 *
 * This file is distributed under the terms in the attached BERKELEY-LICENSE
 * file. If you do not find these files, copies can be found by writing to:
 * Computer Science Division, Database Group, Universite of California,
 * 617 Soda Hall #1776, Berkeley, CA 94720-1776. Attention: Berkeley License
 *
 * Copyright (c) 2003-2004 Intel Corporation. All rights reserved.
 *
 * This file is distributed under the terms in the attached INTEL-LICENSE file.
 * If you do not find these files, copies can be found by writing to:
 * Intel Research Berkeley, 2150 Shattuck Avenue, Suite 1300,
 * Berkeley, CA, 94704.  Attention:  Intel License Inquiry.
 */


package pier.helpers.functions;

import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;

/**
 * Class FunctionConcat
 *
 */
public class FunctionMatchpart extends FunctionIsmatchpart implements Function {

    /**
     * Method evaluate
     *
     * @param parameters
     * @return
     */
    public Object evaluate(Object[] parameters) {
        int params = parameters.length;

        if ((params == 3) || (params == 4) || (params == 5)) {
            String delim1 = parameters[2].toString();
            String delim2 = (params == 4)
                            ? parameters[3].toString()
                            : delim1;
            boolean toDistance = (params == 5)
                                 ? ((Boolean) parameters[4]).booleanValue()
                                 : true;
            ArrayList set1 = (ArrayList) getParts(new ArrayList(),
                                                  parameters[0].toString(),
                                                  delim1);
            ArrayList set2 = (ArrayList) getParts(new ArrayList(),
                                                  parameters[1].toString(),
                                                  delim2);

            return new Integer(haveMatch(set1, set2, toDistance));
        } else {
            return null;
        }
    }

    /**
     * Method getDistance
     *
     * @param count1
     * @param size1
     * @param count2
     * @param size2
     * @param toDistance
     * @return
     */
    protected int getDistance(int count1, int size1, int count2, int size2,
                              boolean toDistance) {
        if (toDistance) {
            if (count1 > count2) {
                return count1;
            } else {
                return count2;
            }
        } else {
            int from1 = size1 - count1;
            int from2 = size2 - count2;

            if (from1 > from2) {
                return from2;
            } else {
                return from1;
            }
        }
    }

    /**
     * Method haveMatch
     *
     * @param set1
     * @param set2
     * @param toDistance
     * @return
     */
    protected int haveMatch(Collection set1, Collection set2,
                            boolean toDistance) {
        int count1 = 0;
        int count2 = 0;
        Iterator iterator1 = set1.iterator();

        while (iterator1.hasNext()) {
            count1++;

            Object head1 = iterator1.next();

            count2 = 0;

            Iterator iterator2 = set2.iterator();

            while (iterator2.hasNext()) {
                count2++;

                Object head2 = iterator2.next();

                if (head1.equals(head2)) {
                    return getDistance(count1, set1.size(), count2,
                                       set2.size(), toDistance);
                }
            }
        }

        return -1;
    }
}