001    /**
002     * Copyright (c) 2000-present Liferay, Inc. All rights reserved.
003     *
004     * This library is free software; you can redistribute it and/or modify it under
005     * the terms of the GNU Lesser General Public License as published by the Free
006     * Software Foundation; either version 2.1 of the License, or (at your option)
007     * any later version.
008     *
009     * This library is distributed in the hope that it will be useful, but WITHOUT
010     * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
011     * FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
012     * details.
013     */
014    
015    package com.liferay.portal.kernel.util;
016    
017    import com.liferay.portal.kernel.bean.BeanPropertiesUtil;
018    
019    import java.io.Serializable;
020    
021    import java.util.Comparator;
022    
023    /**
024     * @author Brian Wing Shun Chan
025     * @author Shuyang Zhou
026     */
027    public abstract class OrderByComparator<T>
028            implements Comparator<T>, Serializable {
029    
030            public String getOrderBy() {
031                    return null;
032            }
033    
034            public String[] getOrderByConditionFields() {
035                    return getOrderByFields();
036            }
037    
038            public Object[] getOrderByConditionValues(Object obj) {
039                    String[] fields = getOrderByConditionFields();
040    
041                    Object[] values = new Object[fields.length];
042    
043                    for (int i = 0; i < fields.length; i++) {
044                            values[i] = BeanPropertiesUtil.getObject(obj, fields[i]);
045                    }
046    
047                    return values;
048            }
049    
050            public String[] getOrderByFields() {
051                    String orderBy = getOrderBy();
052    
053                    if (orderBy == null) {
054                            return null;
055                    }
056    
057                    String[] parts = StringUtil.split(orderBy);
058    
059                    String[] fields = new String[parts.length];
060    
061                    for (int i = 0; i < parts.length; i++) {
062                            String part = parts[i];
063    
064                            int x = part.indexOf(CharPool.PERIOD);
065                            int y = part.indexOf(CharPool.SPACE, x);
066    
067                            if (y == -1) {
068                                    y = part.length();
069                            }
070    
071                            fields[i] = part.substring(x + 1, y);
072                    }
073    
074                    return fields;
075            }
076    
077            public boolean isAscending() {
078                    String orderBy = getOrderBy();
079    
080                    if ((orderBy == null) ||
081                            StringUtil.toUpperCase(orderBy).endsWith(_ORDER_BY_DESC)) {
082    
083                            return false;
084                    }
085                    else {
086                            return true;
087                    }
088            }
089    
090            public boolean isAscending(String field) {
091                    return isAscending();
092            }
093    
094            @Override
095            public String toString() {
096                    return getOrderBy();
097            }
098    
099            private static final String _ORDER_BY_DESC = " DESC";
100    
101    }