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1   /*
2    * Copyright (c) 2000, 2001, 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;
27  
28  import java.sql.*;
29  
30  /**
31   * The facility that a disconnected <code>RowSet</code> object calls on
32   * to populate itself with rows of data. A reader (an object implementing the
33   * <code>RowSetReader</code> interface) may be registered with
34   * a <code>RowSet</code> object that supports the reader/writer paradigm.
35   * When the <code>RowSet</code> object's <code>execute</code> method is
36   * called, it in turn calls the reader's <code>readData</code> method.
37   *
38   * @since 1.4
39   */
40  
41  public interface RowSetReader {
42  
43    /**
44     * Reads the new contents of the calling <code>RowSet</code> object.
45     * In order to call this method, a <code>RowSet</code>
46     * object must have implemented the <code>RowSetInternal</code> interface
47     * and registered this <code>RowSetReader</code> object as its reader.
48     * The <code>readData</code>  method is invoked internally
49     * by the <code>RowSet.execute</code> method for rowsets that support the
50     * reader/writer paradigm.
51     *
52     * <P>The <code>readData</code> method adds rows to the caller.
53     * It can be implemented in a wide variety of ways and can even
54     * populate the caller with rows from a nonrelational data source.
55     * In general, a reader may invoke any of the rowset's methods,
56     * with one exception. Calling the method <code>execute</code> will
57     * cause an <code>SQLException</code> to be thrown
58     * because <code>execute</code> may not be called recursively.  Also,
59     * when a reader invokes <code>RowSet</code> methods, no listeners
60     * are notified; that is, no <code>RowSetEvent</code> objects are
61     * generated and no <code>RowSetListener</code> methods are invoked.
62     * This is true because listeners are already being notified by the method
63     * <code>execute</code>.
64     *
65     * @param caller the <code>RowSet</code> object (1) that has implemented the
66     *         <code>RowSetInternal</code> interface, (2) with which this reader is
67     *        registered, and (3) whose <code>execute</code> method called this reader
68     * @exception SQLException if a database access error occurs or this method
69     *            invokes the <code>RowSet.execute</code> method
70     */
71    void readData(RowSetInternal caller) throws SQLException;
72  
73  }