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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 | +} | |