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| 1 | /* | ||
| 2 | * Copyright (c) 2003, 2004, Oracle and/or its affiliates. All rights reserved. | ||
| 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. | ||
| 4 | * | ||
| 5 | * This code is free software; you can redistribute it and/or modify it | ||
| 6 | * under the terms of the GNU General Public License version 2 only, as | ||
| 7 | * published by the Free Software Foundation. Oracle designates this | ||
| 8 | * particular file as subject to the "Classpath" exception as provided | ||
| 9 | * by Oracle in the LICENSE file that accompanied this code. | ||
| 10 | * | ||
| 11 | * This code is distributed in the hope that it will be useful, but WITHOUT | ||
| 12 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | ||
| 13 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | ||
| 14 | * version 2 for more details (a copy is included in the LICENSE file that | ||
| 15 | * accompanied this code). | ||
| 16 | * | ||
| 17 | * You should have received a copy of the GNU General Public License version | ||
| 18 | * 2 along with this work; if not, write to the Free Software Foundation, | ||
| 19 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. | ||
| 20 | * | ||
| 21 | * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA | ||
| 22 | * or visit www.oracle.com if you need additional information or have any | ||
| 23 | * questions. | ||
| 24 | */ | ||
| 25 | |||
| 26 | package javax.sql.rowset; | ||
| 27 | |||
| 28 | import java.sql.SQLException; | ||
| 29 | |||
| 30 | /** | ||
| 31 | * <h3>1.0 Background</h3> | ||
| 32 | * The <code>Joinable</code> interface provides the methods for getting and | ||
| 33 | * setting a match column, which is the basis for forming the SQL <code>JOIN</code> | ||
| 34 | * formed by adding <code>RowSet</code> objects to a <code>JoinRowSet</code> | ||
| 35 | * object. | ||
| 36 | * <P> | ||
| 37 | * Any standard <code>RowSet</code> implementation <b>may</b> implement | ||
| 38 | * the <code>Joinable</code> interface in order to be | ||
| 39 | * added to a <code>JoinRowSet</code> object. Implementing this interface gives | ||
| 40 | * a <code>RowSet</code> object the ability to use <code>Joinable</code> methods, | ||
| 41 | * which set, retrieve, and get information about match columns. An | ||
| 42 | * application may add a | ||
| 43 | * <code>RowSet</code> object that has not implemented the <code>Joinable</code> | ||
| 44 | * interface to a <code>JoinRowSet</code> object, but to do so it must use one | ||
| 45 | * of the <code>JoinRowSet.addRowSet</code> methods that takes both a | ||
| 46 | * <code>RowSet</code> object and a match column or an array of <code>RowSet</code> | ||
| 47 | * objects and an array of match columns. | ||
| 48 | * <P> | ||
| 49 | * To get access to the methods in the <code>Joinable</code> interface, a | ||
| 50 | * <code>RowSet</code> object implements at least one of the | ||
| 51 | * five standard <code>RowSet</code> interfaces and also implements the | ||
| 52 | * <code>Joinable</code> interface. In addition, most <code>RowSet</code> | ||
| 53 | * objects extend the <code>BaseRowSet</code> class. For example: | ||
| 54 | * <pre> | ||
| 55 | * class MyRowSetImpl extends BaseRowSet implements CachedRowSet, Joinable { | ||
| 56 | * : | ||
| 57 | * : | ||
| 58 | * } | ||
| 59 | * </pre> | ||
| 60 | * <P> | ||
| 61 | * <h3>2.0 Usage Guidelines</h3> | ||
| 62 | * <P> | ||
| 63 | * The methods in the <code>Joinable</code> interface allow a <code>RowSet</code> object | ||
| 64 | * to set a match column, retrieve a match column, or unset a match column, which is | ||
| 65 | * the column upon which an SQL <code>JOIN</code> can be based. | ||
| 66 | * An instance of a class that implements these methods can be added to a | ||
| 67 | * <code>JoinRowSet</code> object to allow an SQL <code>JOIN</code> relationship to | ||
| 68 | * be established. | ||
| 69 | * <p> | ||
| 70 | * <pre> | ||
| 71 | * CachedRowSet crs = new MyRowSetImpl(); | ||
| 72 | * crs.populate((ResultSet)rs); | ||
| 73 | * (Joinable)crs.setMatchColumnIndex(1); | ||
| 74 | * | ||
| 75 | * JoinRowSet jrs = new JoinRowSetImpl(); | ||
| 76 | * jrs.addRowSet(crs); | ||
| 77 | * </pre> | ||
| 78 | * In the previous example, <i>crs</i> is a <code>CachedRowSet</code> object that | ||
| 79 | * has emplemented the <code>Joinable</code> interface. In the following example, | ||
| 80 | * <i>crs2</i> has not, so it must supply the match column as an argument to the | ||
| 81 | * <code>addRowSet</code> method. This example assumes that column 1 is the match | ||
| 82 | * column. | ||
| 83 | * <PRE> | ||
| 84 | * CachedRowSet crs2 = new MyRowSetImpl(); | ||
| 85 | * crs2.populate((ResultSet)rs); | ||
| 86 | * | ||
| 87 | * JoinRowSet jrs2 = new JoinRowSetImpl(); | ||
| 88 | * jrs2.addRowSet(crs2, 1); | ||
| 89 | * </PRE> | ||
| 90 | * <p> | ||
| 91 | * The <code>JoinRowSet</code> interface makes it possible to get data from one or | ||
| 92 | * more <code>RowSet</code> objects consolidated into one table without having to incur | ||
| 93 | * the expense of creating a connection to a database. It is therefore ideally suited | ||
| 94 | * for use by disconnected <code>RowSet</code> objects. Nevertheless, any | ||
| 95 | * <code>RowSet</code> object <b>may</b> implement this interface | ||
| 96 | * regardless of whether it is connected or disconnected. Note that a | ||
| 97 | * <code>JdbcRowSet</code> object, being always connected to its data source, can | ||
| 98 | * become part of an SQL <code>JOIN</code> directly without having to become part | ||
| 99 | * of a <code>JoinRowSet</code> object. | ||
| 100 | * <P> | ||
| 101 | * <h3>3.0 Managing Multiple Match Columns</h3> | ||
| 102 | * The index array passed into the <code>setMatchColumn</code> methods indicates | ||
| 103 | * how many match columns are being set (the length of the array) in addition to | ||
| 104 | * which columns will be used for the match. For example: | ||
| 105 | * <pre> | ||
| 106 | * int[] i = {1, 2, 4, 7}; // indicates four match columns, with column | ||
| 107 | * // indexes 1, 2, 4, 7 participating in the JOIN. | ||
| 108 | * Joinable.setMatchColumn(i); | ||
| 109 | * </pre> | ||
| 110 | * Subsequent match columns may be added as follows to a different <code>Joinable</code> | ||
| 111 | * object (a <code>RowSet</code> object that has implemented the <code>Joinable</code> | ||
| 112 | * interface). | ||
| 113 | * <pre> | ||
| 114 | * int[] w = {3, 2, 5, 3}; | ||
| 115 | * Joinable2.setMatchColumn(w); | ||
| 116 | * </pre> | ||
| 117 | * When an application adds two or more <code>RowSet</code> objects to a | ||
| 118 | * <code>JoinRowSet</code> object, the order of the indexes in the array is | ||
| 119 | * particularly important. Each index of | ||
| 120 | * the array maps directly to the corresponding index of the previously added | ||
| 121 | * <code>RowSet</code> object. If overlap or underlap occurs, the match column | ||
| 122 | * data is maintained in the event an additional <code>Joinable</code> RowSet is | ||
| 123 | * added and needs to relate to the match column data. Therefore, applications | ||
| 124 | * can set multiple match columns in any order, but | ||
| 125 | * this order has a direct effect on the outcome of the <code>SQL</code> JOIN. | ||
| 126 | * <p> | ||
| 127 | * This assertion applies in exactly the same manner when column names are used | ||
| 128 | * rather than column indexes to indicate match columns. | ||
| 129 | * | ||
| 130 | * @see JoinRowSet | ||
| 131 | * @author Jonathan Bruce | ||
| 132 | */ | ||
| 133 | public interface Joinable { | ||
| 134 | |||
| 135 | /** | ||
| 136 | * Sets the designated column as the match column for this <code>RowSet</code> | ||
| 137 | * object. A <code>JoinRowSet</code> object can now add this <code>RowSet</code> | ||
| 138 | * object based on the match column. | ||
| 139 | * <p> | ||
| 140 | * Sub-interfaces such as the <code>CachedRowSet</code><sup><font size=-2>TM</font></sup> | ||
| 141 | * interface define the method <code>CachedRowSet.setKeyColumns</code>, which allows | ||
| 142 | * primary key semantics to be enforced on specific columns. | ||
| 143 | * Implementations of the <code>setMatchColumn(int columnIdx)</code> method | ||
| 144 | * should ensure that the constraints on the key columns are maintained when | ||
| 145 | * a <code>CachedRowSet</code> object sets a primary key column as a match column. | ||
| 146 | * | ||
| 147 | * @param columnIdx an <code>int</code> identifying the index of the column to be | ||
| 148 | * set as the match column | ||
| 149 | * @throws SQLException if an invalid column index is set | ||
| 150 | * @see #setMatchColumn(int[]) | ||
| 151 | * @see #unsetMatchColumn(int) | ||
| 152 | * | ||
| 153 | */ | ||
| 154 | public void setMatchColumn(int columnIdx) throws SQLException; | ||
| 155 | |||
| 156 | /** | ||
| 157 | * Sets the designated columns as the match column for this <code>RowSet</code> | ||
| 158 | * object. A <code>JoinRowSet</code> object can now add this <code>RowSet</code> | ||
| 159 | * object based on the match column. | ||
| 160 | * | ||
| 161 | * @param columnIdxes an array of <code>int</code> identifying the indexes of the | ||
| 162 | * columns to be set as the match columns | ||
| 163 | * @throws SQLException if an invalid column index is set | ||
| 164 | * @see #setMatchColumn(int[]) | ||
| 165 | * @see #unsetMatchColumn(int[]) | ||
| 166 | */ | ||
| 167 | public void setMatchColumn(int[] columnIdxes) throws SQLException; | ||
| 168 | |||
| 169 | /** | ||
| 170 | * Sets the designated column as the match column for this <code>RowSet</code> | ||
| 171 | * object. A <code>JoinRowSet</code> object can now add this <code>RowSet</code> | ||
| 172 | * object based on the match column. | ||
| 173 | * <p> | ||
| 174 | * Subinterfaces such as the <code>CachedRowSet</code> interface define | ||
| 175 | * the method <code>CachedRowSet.setKeyColumns</code>, which allows | ||
| 176 | * primary key semantics to be enforced on specific columns. | ||
| 177 | * Implementations of the <code>setMatchColumn(String columnIdx)</code> method | ||
| 178 | * should ensure that the constraints on the key columns are maintained when | ||
| 179 | * a <code>CachedRowSet</code> object sets a primary key column as a match column. | ||
| 180 | * | ||
| 181 | * @param columnName a <code>String</code> object giving the name of the column | ||
| 182 | * to be set as the match column | ||
| 183 | * @throws SQLException if an invalid column name is set, the column name | ||
| 184 | * is a null, or the column name is an empty string | ||
| 185 | * @see #unsetMatchColumn | ||
| 186 | * @see #setMatchColumn(int[]) | ||
| 187 | */ | ||
| 188 | public void setMatchColumn(String columnName) throws SQLException; | ||
| 189 | |||
| 190 | /** | ||
| 191 | * Sets the designated columns as the match column for this <code>RowSet</code> | ||
| 192 | * object. A <code>JoinRowSet</code> object can now add this <code>RowSet</code> | ||
| 193 | * object based on the match column. | ||
| 194 | * | ||
| 195 | * @param columnNames an array of <code>String</code> objects giving the names | ||
| 196 | * of the column to be set as the match columns | ||
| 197 | * @throws SQLException if an invalid column name is set, the column name | ||
| 198 | * is a null, or the column name is an empty string | ||
| 199 | * @see #unsetMatchColumn | ||
| 200 | * @see #setMatchColumn(int[]) | ||
| 201 | */ | ||
| 202 | public void setMatchColumn(String[] columnNames) throws SQLException; | ||
| 203 | |||
| 204 | /** | ||
| 205 | * Retrieves the indexes of the match columns that were set for this | ||
| 206 | * <code>RowSet</code> object with the method | ||
| 207 | * <code>setMatchColumn(int[] columnIdxes)</code>. | ||
| 208 | * | ||
| 209 | * @return an <code>int</code> array identifying the indexes of the columns | ||
| 210 | * that were set as the match columns for this <code>RowSet</code> object | ||
| 211 | * @throws SQLException if no match column has been set | ||
| 212 | * @see #setMatchColumn | ||
| 213 | * @see #unsetMatchColumn | ||
| 214 | */ | ||
| 215 | public int[] getMatchColumnIndexes() throws SQLException; | ||
| 216 | |||
| 217 | /** | ||
| 218 | * Retrieves the names of the match columns that were set for this | ||
| 219 | * <code>RowSet</code> object with the method | ||
| 220 | * <code>setMatchColumn(String [] columnNames)</code>. | ||
| 221 | * | ||
| 222 | * @return an array of <code>String</code> objects giving the names of the columns | ||
| 223 | * set as the match columns for this <code>RowSet</code> object | ||
| 224 | * @throws SQLException if no match column has been set | ||
| 225 | * @see #setMatchColumn | ||
| 226 | * @see #unsetMatchColumn | ||
| 227 | * | ||
| 228 | */ | ||
| 229 | public String[] getMatchColumnNames() throws SQLException; | ||
| 230 | |||
| 231 | /** | ||
| 232 | * Unsets the designated column as the match column for this <code>RowSet</code> | ||
| 233 | * object. | ||
| 234 | * <P> | ||
| 235 | * <code>RowSet</code> objects that implement the <code>Joinable</code> interface | ||
| 236 | * must ensure that a key-like constraint continues to be enforced until the | ||
| 237 | * method <code>CachedRowSet.unsetKeyColumns</code> has been called on the | ||
| 238 | * designated column. | ||
| 239 | * | ||
| 240 | * @param columnIdx an <code>int</code> that identifies the index of the column | ||
| 241 | * that is to be unset as a match column | ||
| 242 | * @throws SQLException if an invalid column index is designated or if | ||
| 243 | * the designated column was not previously set as a match | ||
| 244 | * column | ||
| 245 | * @see #setMatchColumn | ||
| 246 | */ | ||
| 247 | public void unsetMatchColumn(int columnIdx) throws SQLException; | ||
| 248 | |||
| 249 | /** | ||
| 250 | * Unsets the designated columns as the match column for this <code>RowSet</code> | ||
| 251 | * object. | ||
| 252 | * | ||
| 253 | * @param columnIdxes an arrary of <code>int</code> that identifies the indexes | ||
| 254 | * of the columns that are to be unset as match columns | ||
| 255 | * @throws SQLException if an invalid column index is designated or if | ||
| 256 | * the designated column was not previously set as a match | ||
| 257 | * column | ||
| 258 | * @see #setMatchColumn | ||
| 259 | */ | ||
| 260 | public void unsetMatchColumn(int[] columnIdxes) throws SQLException; | ||
| 261 | |||
| 262 | /** | ||
| 263 | * Unsets the designated column as the match column for this <code>RowSet</code> | ||
| 264 | * object. | ||
| 265 | * <P> | ||
| 266 | * <code>RowSet</code> objects that implement the <code>Joinable</code> interface | ||
| 267 | * must ensure that a key-like constraint continues to be enforced until the | ||
| 268 | * method <code>CachedRowSet.unsetKeyColumns</code> has been called on the | ||
| 269 | * designated column. | ||
| 270 | * | ||
| 271 | * @param columnName a <code>String</code> object giving the name of the column | ||
| 272 | * that is to be unset as a match column | ||
| 273 | * @throws SQLException if an invalid column name is designated or | ||
| 274 | * the designated column was not previously set as a match | ||
| 275 | * column | ||
| 276 | * @see #setMatchColumn | ||
| 277 | */ | ||
| 278 | public void unsetMatchColumn(String columnName) throws SQLException; | ||
| 279 | |||
| 280 | /** | ||
| 281 | * Unsets the designated columns as the match columns for this <code>RowSet</code> | ||
| 282 | * object. | ||
| 283 | * | ||
| 284 | * @param columnName an array of <code>String</code> objects giving the names of | ||
| 285 | * the columns that are to be unset as the match columns | ||
| 286 | * @throws SQLException if an invalid column name is designated or the | ||
| 287 | * designated column was not previously set as a match column | ||
| 288 | * @see #setMatchColumn | ||
| 289 | */ | ||
| 290 | public void unsetMatchColumn(String[] columnName) throws SQLException; | ||
| 291 | } | ||