01: /*
02: * $Id: FilteringRowIterator.java,v 1.11 2005/06/18 01:03:44 ahimanikya Exp $
03: * =======================================================================
04: * Copyright (c) 2002-2005 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.rowiterators;
42:
43: import org.axiondb.AxionException;
44: import org.axiondb.Row;
45: import org.axiondb.RowDecorator;
46: import org.axiondb.RowIterator;
47: import org.axiondb.Selectable;
48:
49: /**
50: * A {@link DelegatingRowIterator} that only returns {@link Row}s
51: * that match a given {@link WhereNode}.
52: *
53: * @version $Revision: 1.11 $ $Date: 2005/06/18 01:03:44 $
54: * @author Rodney Waldhoff
55: * @author Jonathan Giron
56: */
57: public class FilteringRowIterator extends AbstractAcceptingRowIterator {
58:
59: public FilteringRowIterator(RowIterator iterator,
60: RowDecorator decorator, Selectable where) {
61: super (iterator);
62: _decorator = decorator;
63: _where = where;
64: }
65:
66: public String getShortName() {
67: return "Filtering";
68: }
69:
70: public String toString() {
71: return getShortName() + "(" + _where + ")";
72: }
73:
74: protected boolean acceptable(int rowindex, Row row)
75: throws AxionException {
76: // ISO/IEC 9075-2:2003, Section 7.8, General Rule 2 - filter is applied if condition
77: // evaluates to true; null evaluation thus maps to false.
78: Boolean result = (Boolean) _where.evaluate(decorate(rowindex,
79: row));
80: return (result == null) ? false : result.booleanValue();
81: }
82:
83: private RowDecorator decorate(int rowindex, Row row) {
84: _decorator.setRow(rowindex, row);
85: return _decorator;
86: }
87:
88: private RowDecorator _decorator = null;
89: private Selectable _where = null;
90: }
|