PartialStringComparatorEngine.java

/*******************************************************************************
 * Copyright (c) 1998, 2015 Oracle and/or its affiliates. All rights reserved.
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v1.0 and Eclipse Distribution License v. 1.0
 * which accompanies this distribution.
 * The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v10.html
 * and the Eclipse Distribution License is available at
 * http://www.eclipse.org/org/documents/edl-v10.php.
 *
 * Contributors:
 *     Oracle - initial API and implementation from Oracle TopLink
******************************************************************************/
package org.eclipse.persistence.tools.workbench.utility.string;

import java.util.Comparator;

/**
 * This interface defines a protocol for matching up strings from
 * two sets of string holders.
 */
public interface PartialStringComparatorEngine {

    /**
     * Return a set of string holder pairs that reflect the best-matched pairs of
     * strings from the specified sets of string holders. If either of the sets is
     * larger than the other, the strings that are the worst-matched will be
     * paired with nulls.
     */
    StringHolderPair[] match(StringHolder[] stringHolders1, StringHolder[] stringHolders2);


    /**
     * A string holder pair holds a pair of string holders that have been
     * matched up by a partial string comparator engine. It also holds
     * the score assigned to the pair by the engine.
     */
    public interface StringHolderPair extends Comparable {

        /**
         * Return the string holder taken from the first set of string holders.
         */
        StringHolder getStringHolder1();

        /**
         * Return the string holder taken from the second set of string holders.
         */
        StringHolder getStringHolder2();

        /**
         * Return the score that indicates the quality of the match
         * of the pair's strings. The score is between 0.0 and 1.0,
         * inclusive, where a higher score indicates a better match.
         */
        double getScore();

        /**
         * Provide an implementation of Comparator that can be easily used
         * by StringHolderPair implementations to implement Comparable.
         */
        Comparator DEFAULT_COMPARATOR =
            new Comparator() {
                public int compare(Object o1, Object o2) {
                    double score1 = ((StringHolderPair) o1).getScore();
                    double score2 = ((StringHolderPair) o2).getScore();
                    return (score1 < score2) ? -1 : ((score1 == score2) ? 0 : 1);
                }
            };

    }

    /**
     * Straightforward implementation of the StringHolderPair interface.
     */
    public class SimpleStringHolderPair implements StringHolderPair {
        private final StringHolder stringHolder1;
        private final StringHolder stringHolder2;
        private final double score;

        public SimpleStringHolderPair(StringHolder stringHolder1, StringHolder stringHolder2, double score) {
            super();
            this.stringHolder1 = stringHolder1;
            this.stringHolder2 = stringHolder2;
            this.score = score;
        }

        public StringHolder getStringHolder1() {
            return this.stringHolder1;
        }

        public StringHolder getStringHolder2() {
            return this.stringHolder2;
        }

        public double getScore() {
            return this.score;
        }

        public int compareTo(Object o) {
            return DEFAULT_COMPARATOR.compare(this, o);
        }

        public String toString() {
            StringBuffer sb = new StringBuffer(100);
            StringTools.buildSimpleToStringOn(this, sb);
            sb.append(" (");
            this.appendStringHolder(this.stringHolder1, sb);
            sb.append(" vs. ");
            this.appendStringHolder(this.stringHolder2, sb);
            sb.append(" => ");
            sb.append(this.score);
            sb.append(')');
            return sb.toString();
        }

        private void appendStringHolder(StringHolder stringHolder, StringBuffer sb) {
            if (stringHolder == null) {
                sb.append("<null>");
            } else {
                sb.append('"');
                sb.append(stringHolder.getString());
                sb.append('"');
            }
        }

    }

}