01: /*
02: * $Id: SumFunction.java,v 1.4 2005/08/24 00:41:52 ahimanikya Exp $
03: * =======================================================================
04: * Copyright (c) 2002-2003 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.functions;
42:
43: import java.math.BigDecimal;
44:
45: import org.axiondb.AxionException;
46: import org.axiondb.DataType;
47: import org.axiondb.FunctionFactory;
48: import org.axiondb.RowDecoratorIterator;
49: import org.axiondb.Selectable;
50: import org.axiondb.types.BigDecimalType;
51:
52: /**
53: * @version $Revision: 1.4 $ $Date: 2005/08/24 00:41:52 $
54: * @author Rodney Waldhoff
55: */
56: public class SumFunction extends BaseAggregateFunction implements
57: AggregateFunction, FunctionFactory {
58: public SumFunction() {
59: super ("SUM");
60: }
61:
62: public ConcreteFunction makeNewInstance() {
63: return new SumFunction();
64: }
65:
66: public final DataType getDataType() {
67: return _targetType == null ? BIG_DECIMAL_TYPE : _targetType;
68: }
69:
70: public final Object evaluate(RowDecoratorIterator rows)
71: throws AxionException {
72: Selectable sel = getArgument(0);
73: _targetType = sel.getDataType();
74: setDistinct();
75:
76: double rowCount = 0;
77: BigDecimal sum = null;
78: while (rows.hasNext()) {
79: Object val = _targetType.convert(sel.evaluate(rows.next()));
80: if (null != val && acceptable(val)) {
81: rowCount++;
82: sum = evaluate(sum, _targetType.toBigDecimal(val));
83: }
84: }
85: return null != sum ? sum : null;
86: }
87:
88: protected BigDecimal evaluate(BigDecimal src, BigDecimal val) {
89: return null == src ? val : src.add(val);
90: }
91:
92: private DataType _targetType = null;
93: private static final DataType BIG_DECIMAL_TYPE = new BigDecimalType();
94: }
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