| 1 | /* |
| 2 | |
| 3 | Derby - Class org.apache.derby.impl.jdbc.EmbedResultSetMetaData |
| 4 | |
| 5 | Copyright 1997, 2004 The Apache Software Foundation or its licensors, as applicable. |
| 6 | |
| 7 | Licensed under the Apache License, Version 2.0 (the "License"); |
| 8 | you may not use this file except in compliance with the License. |
| 9 | You may obtain a copy of the License at |
| 10 | |
| 11 | http://www.apache.org/licenses/LICENSE-2.0 |
| 12 | |
| 13 | Unless required by applicable law or agreed to in writing, software |
| 14 | distributed under the License is distributed on an "AS IS" BASIS, |
| 15 | WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 16 | See the License for the specific language governing permissions and |
| 17 | limitations under the License. |
| 18 | |
| 19 | */ |
| 20 | |
| 21 | package org.apache.derby.impl.jdbc; |
| 22 | |
| 23 | import org.apache.derby.iapi.sql.ResultDescription; |
| 24 | import org.apache.derby.iapi.sql.ResultColumnDescriptor; |
| 25 | import org.apache.derby.iapi.types.DataTypeDescriptor; |
| 26 | import org.apache.derby.iapi.types.DataTypeUtilities; |
| 27 | import org.apache.derby.iapi.types.TypeId; |
| 28 | |
| 29 | import org.apache.derby.iapi.services.sanity.SanityManager; |
| 30 | |
| 31 | import org.apache.derby.iapi.reference.SQLState; |
| 32 | |
| 33 | import java.sql.ResultSetMetaData; |
| 34 | import java.sql.SQLException; |
| 35 | import java.sql.Types; |
| 36 | import java.sql.ResultSet; |
| 37 | |
| 38 | /** |
| 39 | * A ResultSetMetaData object can be used to find out about the types |
| 40 | * and properties of the columns in a ResultSet. |
| 41 | * |
| 42 | * <p> |
| 43 | * We take the (cloudscape) ResultDescription and examine it, to return |
| 44 | * the appropriate information. |
| 45 | |
| 46 | <P> |
| 47 | This class can be used outside of this package to convert a |
| 48 | ResultDescription into a ResultSetMetaData object. |
| 49 | * |
| 50 | * @author ames |
| 51 | */ |
| 52 | public class EmbedResultSetMetaData |
| 53 | implements ResultSetMetaData { |
| 54 | |
| 55 | private final ResultColumnDescriptor[] columnInfo; |
| 56 | |
| 57 | // |
| 58 | // constructor |
| 59 | // |
| 60 | public EmbedResultSetMetaData(ResultColumnDescriptor[] columnInfo) { |
| 61 | this.columnInfo = columnInfo; |
| 62 | } |
| 63 | |
| 64 | // |
| 65 | // ResultSetMetaData interface |
| 66 | // |
| 67 | |
| 68 | /** |
| 69 | * What's the number of columns in the ResultSet? |
| 70 | * |
| 71 | * @return the number |
| 72 | */ |
| 73 | public int getColumnCount() { |
| 74 | return columnInfo == null ? 0 : columnInfo.length; |
| 75 | } |
| 76 | |
| 77 | /** |
| 78 | * Is the column automatically numbered, thus read-only? |
| 79 | * |
| 80 | * @param column the first column is 1, the second is 2, ... |
| 81 | * @return true if so |
| 82 | * @exception SQLException thrown on failure |
| 83 | * |
| 84 | */ |
| 85 | public boolean isAutoIncrement(int column) throws SQLException { |
| 86 | |
| 87 | ResultColumnDescriptor rcd = columnInfo[column - 1]; |
| 88 | return rcd.isAutoincrement(); |
| 89 | } |
| 90 | |
| 91 | /** |
| 92 | * Does a column's case matter? |
| 93 | * |
| 94 | * @param column the first column is 1, the second is 2, ... |
| 95 | * @return true if so |
| 96 | * @exception SQLException thrown on failure |
| 97 | */ |
| 98 | public boolean isCaseSensitive(int column) throws SQLException { |
| 99 | return DataTypeUtilities.isCaseSensitive(getColumnTypeDescriptor(column)); |
| 100 | } |
| 101 | |
| 102 | |
| 103 | /** |
| 104 | * Can the column be used in a where clause? |
| 105 | * |
| 106 | * @param column the first column is 1, the second is 2, ... |
| 107 | * @return true if so |
| 108 | * @exception SQLException thrown on failure |
| 109 | */ |
| 110 | public boolean isSearchable(int column) throws SQLException { |
| 111 | validColumnNumber(column); |
| 112 | |
| 113 | // we have no restrictions yet, so this is always true |
| 114 | // might eventually be false for e.g. extra-long columns? |
| 115 | return true; |
| 116 | } |
| 117 | |
| 118 | /** |
| 119 | * Is the column a cash value? |
| 120 | * |
| 121 | * @param column the first column is 1, the second is 2, ... |
| 122 | * @return true if so |
| 123 | * @exception SQLException thrown on failure |
| 124 | */ |
| 125 | public boolean isCurrency(int column) throws SQLException { |
| 126 | |
| 127 | return DataTypeUtilities.isCurrency(getColumnTypeDescriptor(column)); |
| 128 | } |
| 129 | |
| 130 | /** |
| 131 | * Can you put a NULL in this column? |
| 132 | * |
| 133 | * @param column the first column is 1, the second is 2, ... |
| 134 | * @return columnNoNulls, columnNullable or columnNullableUnknown |
| 135 | * @exception SQLException thrown on failure |
| 136 | */ |
| 137 | public int isNullable(int column) throws SQLException { |
| 138 | return DataTypeUtilities.isNullable(getColumnTypeDescriptor(column)); |
| 139 | } |
| 140 | |
| 141 | /** |
| 142 | * Is the column a signed number? |
| 143 | * |
| 144 | * @param column the first column is 1, the second is 2, ... |
| 145 | * @return true if so |
| 146 | * @exception SQLException thrown on failure |
| 147 | */ |
| 148 | public boolean isSigned(int column) throws SQLException { |
| 149 | return DataTypeUtilities.isSigned(getColumnTypeDescriptor(column)); |
| 150 | } |
| 151 | |
| 152 | |
| 153 | /** |
| 154 | * What's the column's normal max width in chars? |
| 155 | * |
| 156 | * @param column the first column is 1, the second is 2, ... |
| 157 | * @return max width |
| 158 | * @exception SQLException thrown on failure |
| 159 | */ |
| 160 | public int getColumnDisplaySize(int column) throws SQLException { |
| 161 | return DataTypeUtilities.getColumnDisplaySize(getColumnTypeDescriptor(column)); |
| 162 | } |
| 163 | |
| 164 | /** |
| 165 | * What's the suggested column title for use in printouts and |
| 166 | * displays? |
| 167 | * |
| 168 | * @param column the first column is 1, the second is 2, ... |
| 169 | * @return true if so |
| 170 | * @exception SQLException thrown on failure |
| 171 | */ |
| 172 | public String getColumnLabel(int column) throws SQLException { |
| 173 | ResultColumnDescriptor cd = columnInfo[column - 1]; |
| 174 | String s = cd.getName(); |
| 175 | |
| 176 | // we could get fancier than this, but it's simple |
| 177 | return (s==null? "Column"+Integer.toString(column) : s); |
| 178 | } |
| 179 | |
| 180 | |
| 181 | /** |
| 182 | * What's a column's name? |
| 183 | * |
| 184 | * @param column the first column is 1, the second is 2, ... |
| 185 | * @return column name |
| 186 | * @exception SQLException thrown on failure |
| 187 | */ |
| 188 | public String getColumnName(int column) throws SQLException { |
| 189 | ResultColumnDescriptor cd = columnInfo[column - 1]; |
| 190 | String s = cd.getName(); |
| 191 | // database returns null when no column name to differentiate from empty name |
| 192 | return (s==null? "" : s); |
| 193 | |
| 194 | } |
| 195 | |
| 196 | |
| 197 | /** |
| 198 | * What's a column's table's schema? |
| 199 | * |
| 200 | * @param column the first column is 1, the second is 2, ... |
| 201 | * @return schema name or "" if not applicable |
| 202 | * @exception SQLException thrown on failure |
| 203 | */ |
| 204 | public String getSchemaName(int column) throws SQLException { |
| 205 | ResultColumnDescriptor cd = columnInfo[column - 1]; |
| 206 | |
| 207 | String s = cd.getSourceSchemaName(); |
| 208 | // database returns null when no schema name to differentiate from empty name |
| 209 | return (s==null? "" : s); |
| 210 | } |
| 211 | |
| 212 | /** |
| 213 | * What's a column's number of decimal digits? |
| 214 | * |
| 215 | * @param column the first column is 1, the second is 2, ... |
| 216 | * @return precision |
| 217 | * @exception SQLException thrown on failure |
| 218 | */ |
| 219 | public int getPrecision(int column) throws SQLException { |
| 220 | return DataTypeUtilities.getDigitPrecision(getColumnTypeDescriptor(column)); |
| 221 | } |
| 222 | |
| 223 | |
| 224 | /** |
| 225 | * What's a column's number of digits to right of the decimal point? |
| 226 | * |
| 227 | * @param column the first column is 1, the second is 2, ... |
| 228 | * @return scale |
| 229 | * @exception SQLException thrown on failure |
| 230 | */ |
| 231 | public int getScale(int column) throws SQLException { |
| 232 | DataTypeDescriptor dtd = getColumnTypeDescriptor(column); |
| 233 | // REMIND -- check it is valid to ask for scale |
| 234 | return dtd.getScale(); |
| 235 | } |
| 236 | |
| 237 | /** |
| 238 | * What's a column's table name? |
| 239 | * |
| 240 | * @return table name or "" if not applicable |
| 241 | * @exception SQLException thrown on failure |
| 242 | */ |
| 243 | public String getTableName(int column) throws SQLException { |
| 244 | ResultColumnDescriptor cd = columnInfo[column - 1]; |
| 245 | String s = cd.getSourceTableName(); |
| 246 | |
| 247 | // database returns null when no table name to differentiate from empty name |
| 248 | return (s==null? "" : s); |
| 249 | } |
| 250 | |
| 251 | /** |
| 252 | * What's a column's table's catalog name? |
| 253 | * |
| 254 | * @param column the first column is 1, the second is 2, ... |
| 255 | * @return column name or "" if not applicable. |
| 256 | * @exception SQLException thrown on failure |
| 257 | */ |
| 258 | public String getCatalogName(int column) throws SQLException { |
| 259 | validColumnNumber(column); |
| 260 | return ""; |
| 261 | } |
| 262 | |
| 263 | /** |
| 264 | * What's a column's SQL type? |
| 265 | * |
| 266 | * @param column the first column is 1, the second is 2, ... |
| 267 | * @return SQL type |
| 268 | * @see Types |
| 269 | * @exception SQLException thrown on failure |
| 270 | */ |
| 271 | public int getColumnType(int column) throws SQLException { |
| 272 | DataTypeDescriptor dtd = getColumnTypeDescriptor(column); |
| 273 | return dtd.getTypeId().getJDBCTypeId(); |
| 274 | } |
| 275 | |
| 276 | /** |
| 277 | * What's a column's data source specific type name? |
| 278 | * |
| 279 | * @param column the first column is 1, the second is 2, ... |
| 280 | * @return type name |
| 281 | * @exception SQLException thrown on failure |
| 282 | */ |
| 283 | public String getColumnTypeName(int column) throws SQLException { |
| 284 | DataTypeDescriptor dtd = getColumnTypeDescriptor(column); |
| 285 | return dtd.getTypeId().getSQLTypeName(); |
| 286 | } |
| 287 | |
| 288 | /** |
| 289 | * Is a column definitely not writable? |
| 290 | * |
| 291 | * @param column the first column is 1, the second is 2, ... |
| 292 | * @return true if so |
| 293 | * @exception SQLException thrown on failure |
| 294 | */ |
| 295 | public boolean isReadOnly(int column) throws SQLException { |
| 296 | validColumnNumber(column); |
| 297 | |
| 298 | // we just don't know if it is a base table column or not |
| 299 | return false; |
| 300 | } |
| 301 | |
| 302 | /** |
| 303 | * Is it possible for a write on the column to succeed? |
| 304 | * |
| 305 | * @param column the first column is 1, the second is 2, ... |
| 306 | * @return true if so |
| 307 | * @exception SQLException thrown on failure |
| 308 | */ |
| 309 | public boolean isWritable(int column) throws SQLException { |
| 310 | validColumnNumber(column); |
| 311 | return columnInfo[column - 1].updatableByCursor(); |
| 312 | } |
| 313 | |
| 314 | /** |
| 315 | * Will a write on the column definitely succeed? |
| 316 | * |
| 317 | * @param column the first column is 1, the second is 2, ... |
| 318 | * @return true if so |
| 319 | * @exception SQLException thrown on failure |
| 320 | */ |
| 321 | public boolean isDefinitelyWritable(int column) throws SQLException { |
| 322 | validColumnNumber(column); |
| 323 | |
| 324 | // we just don't know if it is a base table column or not |
| 325 | return false; |
| 326 | } |
| 327 | |
| 328 | /* |
| 329 | * class interface |
| 330 | */ |
| 331 | |
| 332 | private void validColumnNumber(int column) throws SQLException { |
| 333 | if (column < 1 || |
| 334 | column > getColumnCount() ) |
| 335 | throw Util.generateCsSQLException( |
| 336 | SQLState.COLUMN_NOT_FOUND, new Integer(column)); |
| 337 | } |
| 338 | |
| 339 | public DataTypeDescriptor getColumnTypeDescriptor(int column) throws SQLException |
| 340 | { |
| 341 | validColumnNumber(column); |
| 342 | |
| 343 | ResultColumnDescriptor cd = columnInfo[column - 1]; |
| 344 | |
| 345 | return cd.getType(); |
| 346 | } |
| 347 | |
| 348 | ///////////////////////////////////////////////////////////////////////// |
| 349 | // |
| 350 | // JDBC 2.0 - New public methods |
| 351 | // |
| 352 | ///////////////////////////////////////////////////////////////////////// |
| 353 | |
| 354 | /** |
| 355 | * JDBC 2.0 |
| 356 | * |
| 357 | * <p>Return the fully qualified name of the Java class whose instances |
| 358 | * are manufactured if ResultSet.getObject() is called to retrieve a value |
| 359 | * from the column. ResultSet.getObject() may return a subClass of the |
| 360 | * class returned by this method. |
| 361 | * |
| 362 | * @exception SQLException Feature not inplemented for now. |
| 363 | */ |
| 364 | public String getColumnClassName(int column) throws SQLException { |
| 365 | |
| 366 | return getColumnTypeDescriptor(column).getTypeId().getResultSetMetaDataTypeName(); |
| 367 | } |
| 368 | |
| 369 | |
| 370 | public static ResultColumnDescriptor getResultColumnDescriptor(String name, int jdcbTypeId, boolean nullable) { |
| 371 | |
| 372 | return new org.apache.derby.impl.sql.GenericColumnDescriptor( |
| 373 | name, DataTypeDescriptor.getBuiltInDataTypeDescriptor(jdcbTypeId, nullable)); |
| 374 | } |
| 375 | public static ResultColumnDescriptor getResultColumnDescriptor(String name, int jdcbTypeId, boolean nullable, int length) { |
| 376 | |
| 377 | return new org.apache.derby.impl.sql.GenericColumnDescriptor( |
| 378 | name, DataTypeDescriptor.getBuiltInDataTypeDescriptor(jdcbTypeId, nullable, length)); |
| 379 | } |
| 380 | public static ResultColumnDescriptor getResultColumnDescriptor(String name, DataTypeDescriptor dtd) { |
| 381 | return new org.apache.derby.impl.sql.GenericColumnDescriptor(name, dtd); |
| 382 | } |
| 383 | } |