001    /**
002     * Copyright (c) 2000-2013 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.dao.db;
016    
017    import com.liferay.portal.kernel.util.StringBundler;
018    import com.liferay.portal.kernel.util.StringPool;
019    import com.liferay.portal.kernel.util.StringUtil;
020    
021    /**
022     * @author James Lefeu
023     * @author Peter Shin
024     */
025    public class IndexMetadataFactoryUtil {
026    
027            public static IndexMetadata createIndexMetadata(
028                    boolean unique, String tableName, String... columnNames) {
029    
030                    String specification = _getSpecification(tableName, columnNames);
031    
032                    String indexName = _getIndexName(specification);
033    
034                    StringBundler sb = new StringBundler(5);
035    
036                    if (!unique) {
037                            sb.append("create ");
038                    }
039                    else {
040                            sb.append("create unique ");
041                    }
042    
043                    sb.append("index ");
044                    sb.append(indexName);
045                    sb.append(" on ");
046                    sb.append(specification);
047    
048                    String createSQL = sb.toString();
049    
050                    sb.setIndex(0);
051    
052                    sb.append("drop index ");
053                    sb.append(indexName);
054                    sb.append(" on ");
055                    sb.append(tableName);
056    
057                    String dropSQL = sb.toString();
058    
059                    return new IndexMetadata(
060                            indexName, tableName, unique, specification, createSQL, dropSQL);
061            }
062    
063            private static String _getIndexName(String specification) {
064                    String specificationHash = StringUtil.toHexString(
065                            specification.hashCode());
066    
067                    specificationHash = specificationHash.toUpperCase();
068    
069                    return _INDEX_NAME_PREFIX.concat(specificationHash);
070            }
071    
072            private static String _getSpecification(
073                    String tableName, String[] columnNames) {
074    
075                    StringBundler sb = new StringBundler(6);
076    
077                    sb.append(tableName);
078                    sb.append(StringPool.SPACE);
079                    sb.append(StringPool.OPEN_PARENTHESIS);
080    
081                    if ((columnNames != null) && (columnNames.length > 0)) {
082                            sb.append(
083                                    StringUtil.merge(columnNames, StringPool.COMMA_AND_SPACE));
084                    }
085    
086                    sb.append(StringPool.CLOSE_PARENTHESIS);
087                    sb.append(StringPool.SEMICOLON);
088    
089                    return sb.toString();
090            }
091    
092            private static final String _INDEX_NAME_PREFIX = "IX_";
093    
094    }