org.emonocot.model.compare.ReferenceComparator.java Source code

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Here is the source code for org.emonocot.model.compare.ReferenceComparator.java

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/*
 * This is eMonocot, a global online biodiversity information resource.
 *
 * Copyright  20112015 The Board of Trustees of the Royal Botanic Gardens, Kew and The University of Oxford
 *
 * eMonocot is free software: you can redistribute it and/or modify it under the terms of the
 * GNU Affero General Public License as published by the Free Software Foundation, either version 3
 * of the License, or (at your option) any later version.
 *
 * eMonocot 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 Affero General Public License for more details.
 *
 * The complete text of the GNU Affero General Public License is in the source repository as the file
 * COPYING.  It is also available from <http://www.gnu.org/licenses/>.
 */
package org.emonocot.model.compare;

import java.util.Comparator;

import org.apache.commons.collections.comparators.NullComparator;
import org.emonocot.model.Reference;

public class ReferenceComparator implements Comparator<Reference> {

    private NullComparator nullSafeStringComparator;

    public ReferenceComparator() {
        Comparator<String> stringComparator = new Comparator<String>() {

            @Override
            public int compare(String o1, String o2) {
                return o1.compareTo(o2);
            }

        };
        nullSafeStringComparator = new NullComparator(stringComparator, false);
    }

    @Override
    public int compare(Reference o1, Reference o2) {
        int compareDate = nullSafeStringComparator.compare(o1.getDate(), o2.getDate());
        if (compareDate == 0) {
            int compareAuthor = nullSafeStringComparator.compare(o1.getCreator(), o2.getCreator());
            if (compareAuthor == 0) {
                int compareTitle = nullSafeStringComparator.compare(o1.getTitle(), o2.getTitle());
                if (compareTitle == 0) {
                    return nullSafeStringComparator.compare(o1.getBibliographicCitation(),
                            o2.getBibliographicCitation());
                } else {
                    return compareTitle;
                }
            } else {
                return compareAuthor;
            }
        } else {
            return -1 * compareDate;
        }
    }

}