01: /*
02: * $Id: FlattenWhereNodeVisitor.java,v 1.6 2005/12/22 09:02:29 ahimanikya Exp $
03: * =======================================================================
04: * Copyright (c) 2002-2004 Axion Development Team. All rights reserved.
05: *
06: * Redistribution and use in source and binary forms, with or without
07: * modification, are permitted provided that the following conditions
08: * are met:
09: *
10: * 1. Redistributions of source code must retain the above
11: * copyright notice, this list of conditions and the following
12: * disclaimer.
13: *
14: * 2. Redistributions in binary form must reproduce the above copyright
15: * notice, this list of conditions and the following disclaimer in
16: * the documentation and/or other materials provided with the
17: * distribution.
18: *
19: * 3. The names "Tigris", "Axion", nor the names of its contributors may
20: * not be used to endorse or promote products derived from this
21: * software without specific prior written permission.
22: *
23: * 4. Products derived from this software may not be called "Axion", nor
24: * may "Tigris" or "Axion" appear in their names without specific prior
25: * written permission.
26: *
27: * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
28: * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
29: * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
30: * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
31: * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
32: * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
33: * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
34: * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
35: * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
36: * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
37: * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
38: * =======================================================================
39: */
40:
41: package org.axiondb.engine.visitors;
42:
43: import java.util.LinkedHashSet;
44: import java.util.Set;
45:
46: import org.axiondb.Selectable;
47: import org.axiondb.SelectableVisitor;
48: import org.axiondb.functions.AndFunction;
49:
50: /**
51: * Decomposes a {@link WhereNode}tree into a {@link LinkedHashSet}of {@link WhereNode}s that
52: * were originally ANDed together in the source tree.
53: *
54: * @author Morgan Delagrange
55: * @author Chuck Burdick
56: * @author Ahimanikya Satapathy
57: */
58: public class FlattenWhereNodeVisitor implements SelectableVisitor {
59:
60: protected Set _nodes;
61:
62: public Set getNodes(Selectable node) {
63: _nodes = new LinkedHashSet();
64: visit(node);
65: return _nodes;
66: }
67:
68: public void visit(Selectable sel) {
69: if (sel instanceof AndFunction) {
70: AndFunction fn = (AndFunction) sel;
71: for (int i = 0, I = fn.getArgumentCount(); i < I; i++) {
72: visit(fn.getArgument(i));
73: }
74: } else if (sel != null) {
75: _nodes.add(sel);
76: }
77: }
78:
79: }
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