01: /*
02: * $Id: HexFunction.java,v 1.2 2005/03/05 01:35:35 ahimanikya Exp $
03: * =======================================================================
04: * Copyright (c) 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.StringType;
48:
49: /**
50: * @version $Revision: 1.2 $ $Date: 2005/03/05 01:35:35 $
51: * @author Ahimanikya Satapathy
52: */
53: public class HexFunction extends BaseFunction implements
54: ScalarFunction, FunctionFactory {
55:
56: public HexFunction() {
57: super ("HEX");
58: }
59:
60: public ConcreteFunction makeNewInstance() {
61: return new HexFunction();
62: }
63:
64: public DataType getDataType() {
65: return STRING_TYPE;
66: }
67:
68: public Object evaluate(RowDecorator row) throws AxionException {
69: Object val = getArgument(0).evaluate(row);
70: String strval = (String) (STRING_TYPE.convert(val));
71: if (null == strval) {
72: return null;
73: }
74: return toHex(strval.getBytes());
75: }
76:
77: private String toHex(byte[] data) {
78: int dataLen = data.length;
79: char[] out = new char[dataLen << 1];
80:
81: // two characters form the hex value.
82: for (int i = 0, j = 0; i < dataLen; i++) {
83: out[j++] = DIGITS[(0xF0 & data[i]) >>> 4];
84: out[j++] = DIGITS[0x0F & data[i]];
85: }
86:
87: return new String(out);
88: }
89:
90: public boolean isValid() {
91: return (getArgumentCount() == 1);
92: }
93:
94: private static final char[] DIGITS = { '0', '1', '2', '3', '4',
95: '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' };
96: private static final DataType STRING_TYPE = new StringType();
97: }
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