01: /*
02: * $Id: CastAsFunction.java,v 1.7 2005/05/02 22:28:41 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.functions;
42:
43: import org.axiondb.AxionException;
44: import org.axiondb.DataType;
45: import org.axiondb.FunctionFactory;
46: import org.axiondb.RowDecorator;
47: import org.axiondb.types.AnyType;
48: import org.axiondb.types.CharacterType;
49: import org.axiondb.types.CharacterVaryingType;
50:
51: /**
52: * ANSI style CAST...AS Function function : CAST( {id|expr} AS type[(precision[,scale])] )
53: *
54: * @author Ritesh Adval
55: * @author Ahimanikya Satapathy
56: * @author Jonathan Giron
57: */
58: public class CastAsFunction extends BaseFunction implements
59: ScalarFunction, FunctionFactory {
60:
61: public CastAsFunction() {
62: super ("CASTAS");
63: }
64:
65: public Object evaluate(RowDecorator row) throws AxionException {
66: Object val = getArgument(0).evaluate(row);
67: _targetType = getArgument(1).getDataType();
68: if (null == val) {
69: return null;
70: } else {
71: if (_targetType instanceof CharacterType
72: || _targetType instanceof CharacterVaryingType) {
73: String sourceStr = val.toString();
74: if (sourceStr.length() > _targetType.getPrecision()) {
75: sourceStr = sourceStr.substring(0, _targetType
76: .getPrecision());
77: }
78: return _targetType.convert(sourceStr);
79: } else {
80: return _targetType.convert(val);
81: }
82: }
83: }
84:
85: public DataType getDataType() {
86: return _targetType == null ? ANY_TYPE : _targetType;
87: }
88:
89: public boolean isValid() {
90: return (getArgumentCount() == 2);
91: }
92:
93: public ConcreteFunction makeNewInstance() {
94: return new CastAsFunction();
95: }
96:
97: private DataType _targetType = null;
98: private static final DataType ANY_TYPE = new AnyType();
99: }
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