01: package com.quadcap.sql;
02:
03: /* Copyright 1999 - 2003 Quadcap Software. All rights reserved.
04: *
05: * This software is distributed under the Quadcap Free Software License.
06: * This software may be used or modified for any purpose, personal or
07: * commercial. Open Source redistributions are permitted. Commercial
08: * redistribution of larger works derived from, or works which bundle
09: * this software requires a "Commercial Redistribution License"; see
10: * http://www.quadcap.com/purchase.
11: *
12: * Redistributions qualify as "Open Source" under one of the following terms:
13: *
14: * Redistributions are made at no charge beyond the reasonable cost of
15: * materials and delivery.
16: *
17: * Redistributions are accompanied by a copy of the Source Code or by an
18: * irrevocable offer to provide a copy of the Source Code for up to three
19: * years at the cost of materials and delivery. Such redistributions
20: * must allow further use, modification, and redistribution of the Source
21: * Code under substantially the same terms as this license.
22: *
23: * Redistributions of source code must retain the copyright notices as they
24: * appear in each source code file, these license terms, and the
25: * disclaimer/limitation of liability set forth as paragraph 6 below.
26: *
27: * Redistributions in binary form must reproduce this Copyright Notice,
28: * these license terms, and the disclaimer/limitation of liability set
29: * forth as paragraph 6 below, in the documentation and/or other materials
30: * provided with the distribution.
31: *
32: * The Software is provided on an "AS IS" basis. No warranty is
33: * provided that the Software is free of defects, or fit for a
34: * particular purpose.
35: *
36: * Limitation of Liability. Quadcap Software shall not be liable
37: * for any damages suffered by the Licensee or any third party resulting
38: * from use of the Software.
39: */
40:
41: import java.io.IOException;
42:
43: import java.sql.SQLException;
44:
45: /**
46: * Half of a <b>UNION</b> join. Can be used to synthesize <b>UNION</b> and
47: * <b>FULL</b> joins.
48: *
49: * @author Stan Bailes
50: */
51: public class JoinUnionCursor extends JoinCursor {
52: boolean beforeSecond = true;
53:
54: public JoinUnionCursor(Session session, Cursor outer, Cursor ca,
55: Cursor cb, Expression where, Tuple tuple, JoinMapRow row)
56: throws SQLException {
57: super (session, outer, ca, cb, where, tuple, row, false, false);
58: }
59:
60: public boolean next() throws SQLException {
61: boolean ret = false;
62: if (beforeSecond) {
63: ret = anext();
64: if (!ret) {
65: beforeSecond = false;
66: ret = bnext();
67: }
68: } else {
69: ret = bnext();
70: }
71: return ret;
72: }
73: }
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