001 /* 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017 package org.apache.commons.dbutils; 018 019 import java.sql.ResultSet; 020 import java.sql.ResultSetMetaData; 021 import java.sql.SQLException; 022 import java.util.HashMap; 023 import java.util.List; 024 import java.util.Map; 025 026 /** 027 * Basic implementation of the <code>RowProcessor</code> interface. 028 * 029 * <p> 030 * This class is thread-safe. 031 * </p> 032 * 033 * @see RowProcessor 034 */ 035 public class BasicRowProcessor implements RowProcessor { 036 037 /** 038 * The default BeanProcessor instance to use if not supplied in the 039 * constructor. 040 */ 041 private static final BeanProcessor defaultConvert = new BeanProcessor(); 042 043 /** 044 * The Singleton instance of this class. 045 */ 046 private static final BasicRowProcessor instance = new BasicRowProcessor(); 047 048 /** 049 * Returns the Singleton instance of this class. 050 * 051 * @return The single instance of this class. 052 * @deprecated Create instances with the constructors instead. This will 053 * be removed after DbUtils 1.1. 054 */ 055 public static BasicRowProcessor instance() { 056 return instance; 057 } 058 059 /** 060 * Use this to process beans. 061 */ 062 private final BeanProcessor convert; 063 064 /** 065 * BasicRowProcessor constructor. Bean processing defaults to a 066 * BeanProcessor instance. 067 */ 068 public BasicRowProcessor() { 069 this(defaultConvert); 070 } 071 072 /** 073 * BasicRowProcessor constructor. 074 * @param convert The BeanProcessor to use when converting columns to 075 * bean properties. 076 * @since DbUtils 1.1 077 */ 078 public BasicRowProcessor(BeanProcessor convert) { 079 super(); 080 this.convert = convert; 081 } 082 083 /** 084 * Convert a <code>ResultSet</code> row into an <code>Object[]</code>. 085 * This implementation copies column values into the array in the same 086 * order they're returned from the <code>ResultSet</code>. Array elements 087 * will be set to <code>null</code> if the column was SQL NULL. 088 * 089 * @see org.apache.commons.dbutils.RowProcessor#toArray(java.sql.ResultSet) 090 * @param rs ResultSet that supplies the array data 091 * @throws SQLException if a database access error occurs 092 * @return the newly created array 093 */ 094 public Object[] toArray(ResultSet rs) throws SQLException { 095 ResultSetMetaData meta = rs.getMetaData(); 096 int cols = meta.getColumnCount(); 097 Object[] result = new Object[cols]; 098 099 for (int i = 0; i < cols; i++) { 100 result[i] = rs.getObject(i + 1); 101 } 102 103 return result; 104 } 105 106 /** 107 * Convert a <code>ResultSet</code> row into a JavaBean. This 108 * implementation delegates to a BeanProcessor instance. 109 * @see org.apache.commons.dbutils.RowProcessor#toBean(java.sql.ResultSet, java.lang.Class) 110 * @see org.apache.commons.dbutils.BeanProcessor#toBean(java.sql.ResultSet, java.lang.Class) 111 * @param <T> The type of bean to create 112 * @param rs ResultSet that supplies the bean data 113 * @param type Class from which to create the bean instance 114 * @throws SQLException if a database access error occurs 115 * @return the newly created bean 116 */ 117 public <T> T toBean(ResultSet rs, Class<T> type) throws SQLException { 118 return this.convert.toBean(rs, type); 119 } 120 121 /** 122 * Convert a <code>ResultSet</code> into a <code>List</code> of JavaBeans. 123 * This implementation delegates to a BeanProcessor instance. 124 * @see org.apache.commons.dbutils.RowProcessor#toBeanList(java.sql.ResultSet, java.lang.Class) 125 * @see org.apache.commons.dbutils.BeanProcessor#toBeanList(java.sql.ResultSet, java.lang.Class) 126 * @param <T> The type of bean to create 127 * @param rs ResultSet that supplies the bean data 128 * @param type Class from which to create the bean instance 129 * @throws SQLException if a database access error occurs 130 * @return A <code>List</code> of beans with the given type in the order 131 * they were returned by the <code>ResultSet</code>. 132 */ 133 public <T> List<T> toBeanList(ResultSet rs, Class<T> type) throws SQLException { 134 return this.convert.toBeanList(rs, type); 135 } 136 137 /** 138 * Convert a <code>ResultSet</code> row into a <code>Map</code>. This 139 * implementation returns a <code>Map</code> with case insensitive column 140 * names as keys. Calls to <code>map.get("COL")</code> and 141 * <code>map.get("col")</code> return the same value. 142 * @see org.apache.commons.dbutils.RowProcessor#toMap(java.sql.ResultSet) 143 * @param rs ResultSet that supplies the map data 144 * @throws SQLException if a database access error occurs 145 * @return the newly created Map 146 */ 147 public Map<String, Object> toMap(ResultSet rs) throws SQLException { 148 Map<String, Object> result = new CaseInsensitiveHashMap(); 149 ResultSetMetaData rsmd = rs.getMetaData(); 150 int cols = rsmd.getColumnCount(); 151 152 for (int i = 1; i <= cols; i++) { 153 result.put(rsmd.getColumnName(i), rs.getObject(i)); 154 } 155 156 return result; 157 } 158 159 /** 160 * A Map that converts all keys to lowercase Strings for case insensitive 161 * lookups. This is needed for the toMap() implementation because 162 * databases don't consistenly handle the casing of column names. 163 * 164 * <p>The keys are stored as they are given [BUG #DBUTILS-34], so we maintain 165 * an internal mapping from lowercase keys to the real keys in order to 166 * achieve the case insensitive lookup. 167 * 168 * <p>Note: This implementation does not allow <tt>null</tt> 169 * for key, whereas {@link HashMap} does, because of the code: 170 * <pre> 171 * key.toString().toLowerCase() 172 * </pre> 173 */ 174 private static class CaseInsensitiveHashMap extends HashMap<String, Object> { 175 /** 176 * The internal mapping from lowercase keys to the real keys. 177 * 178 * <p> 179 * Any query operation using the key 180 * ({@link #get(Object)}, {@link #containsKey(Object)}) 181 * is done in three steps: 182 * <ul> 183 * <li>convert the parameter key to lower case</li> 184 * <li>get the actual key that corresponds to the lower case key</li> 185 * <li>query the map with the actual key</li> 186 * </ul> 187 * </p> 188 */ 189 private final Map<String,String> lowerCaseMap = new HashMap<String,String>(); 190 191 /** 192 * Required for serialization support. 193 * 194 * @see java.io.Serializable 195 */ 196 private static final long serialVersionUID = -2848100435296897392L; 197 198 /** {@inheritDoc} */ 199 @Override 200 public boolean containsKey(Object key) { 201 Object realKey = lowerCaseMap.get(key.toString().toLowerCase()); 202 return super.containsKey(realKey); 203 // Possible optimisation here: 204 // Since the lowerCaseMap contains a mapping for all the keys, 205 // we could just do this: 206 // return lowerCaseMap.containsKey(key.toString().toLowerCase()); 207 } 208 209 /** {@inheritDoc} */ 210 @Override 211 public Object get(Object key) { 212 Object realKey = lowerCaseMap.get(key.toString().toLowerCase()); 213 return super.get(realKey); 214 } 215 216 /** {@inheritDoc} */ 217 @Override 218 public Object put(String key, Object value) { 219 /* 220 * In order to keep the map and lowerCaseMap synchronized, 221 * we have to remove the old mapping before putting the 222 * new one. Indeed, oldKey and key are not necessaliry equals. 223 * (That's why we call super.remove(oldKey) and not just 224 * super.put(key, value)) 225 */ 226 Object oldKey = lowerCaseMap.put(key.toLowerCase(), key); 227 Object oldValue = super.remove(oldKey); 228 super.put(key, value); 229 return oldValue; 230 } 231 232 /** {@inheritDoc} */ 233 @Override 234 public void putAll(Map<? extends String,?> m) { 235 for (Map.Entry<? extends String, ?> entry : m.entrySet()) { 236 String key = entry.getKey(); 237 Object value = entry.getValue(); 238 this.put(key, value); 239 } 240 } 241 242 /** {@inheritDoc} */ 243 @Override 244 public Object remove(Object key) { 245 Object realKey = lowerCaseMap.remove(key.toString().toLowerCase()); 246 return super.remove(realKey); 247 } 248 } 249 250 }