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.ArrayUtil;
018    import com.liferay.portal.kernel.util.StringBundler;
019    import com.liferay.portal.kernel.util.StringPool;
020    import com.liferay.portal.kernel.util.StringUtil;
021    
022    /**
023     * @author James Lefeu
024     * @author Peter Shin
025     */
026    public class IndexMetadataFactoryUtil {
027    
028            public static IndexMetadata createIndexMetadata(
029                    boolean unique, String tableName, String... columnNames) {
030    
031                    String specification = _getSpecification(tableName, columnNames);
032    
033                    String indexName = _getIndexName(specification);
034    
035                    StringBundler sb = new StringBundler(5);
036    
037                    if (!unique) {
038                            sb.append("create ");
039                    }
040                    else {
041                            sb.append("create unique ");
042                    }
043    
044                    sb.append("index ");
045                    sb.append(indexName);
046                    sb.append(" on ");
047                    sb.append(specification);
048    
049                    String createSQL = sb.toString();
050    
051                    sb.setIndex(0);
052    
053                    sb.append("drop index ");
054                    sb.append(indexName);
055                    sb.append(" on ");
056                    sb.append(tableName);
057    
058                    String dropSQL = sb.toString();
059    
060                    return new IndexMetadata(
061                            indexName, tableName, unique, specification, createSQL, dropSQL);
062            }
063    
064            private static String _getIndexName(String specification) {
065                    String specificationHash = StringUtil.toHexString(
066                            specification.hashCode());
067    
068                    specificationHash = StringUtil.toUpperCase(specificationHash);
069    
070                    return _INDEX_NAME_PREFIX.concat(specificationHash);
071            }
072    
073            private static String _getSpecification(
074                    String tableName, String[] columnNames) {
075    
076                    StringBundler sb = new StringBundler(6);
077    
078                    sb.append(tableName);
079                    sb.append(StringPool.SPACE);
080                    sb.append(StringPool.OPEN_PARENTHESIS);
081    
082                    if (ArrayUtil.isNotEmpty(columnNames)) {
083                            sb.append(
084                                    StringUtil.merge(columnNames, StringPool.COMMA_AND_SPACE));
085                    }
086    
087                    sb.append(StringPool.CLOSE_PARENTHESIS);
088                    sb.append(StringPool.SEMICOLON);
089    
090                    return sb.toString();
091            }
092    
093            private static final String _INDEX_NAME_PREFIX = "IX_";
094    
095    }