1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17 package org.apache.commons.validator.routines.checkdigit;
18
19 /**
20 * Modulus 10 <b>CUSIP</b> (North American Securities)
21 * Check Digit calculation/validation.
22 * <p>
23 * CUSIP Numbers are 9 character alphanumeric codes used
24 * to identify North American Securities.
25 * <p>
26 * Check digit calculation uses the <i>Modulus 10 Double Add Double</i> technique
27 * with every second digit being weighted by 2. Alphabetic characters are
28 * converted to numbers by their position in the alphabet starting with A being 10.
29 * Weighted numbers greater than ten are treated as two separate numbers.
30 * <p>
31 *
32 * <p>
33 * See <a href="http://en.wikipedia.org/wiki/CUSIP">Wikipedia - CUSIP</a>
34 * for more details.
35 *
36 * @version $Revision: 1227719 $ $Date: 2012-01-05 18:45:51 +0100 (Do, 05 Jan 2012) $
37 * @since Validator 1.4
38 */
39 public final class CUSIPCheckDigit extends ModulusCheckDigit {
40
41 private static final long serialVersionUID = 666941918490152456L;
42
43 /** Singleton CUSIP Check Digit instance */
44 public static final CheckDigit CUSIP_CHECK_DIGIT = new CUSIPCheckDigit();
45
46 /** weighting given to digits depending on their right position */
47 private static final int[] POSITION_WEIGHT = new int[] {2, 1};
48
49 /**
50 * Construct an CUSIP Indetifier Check Digit routine.
51 */
52 public CUSIPCheckDigit() {
53 super(10);
54 }
55
56 /**
57 * Convert a character at a specified position to an integer value.
58 *
59 * @param character The character to convert
60 * @param leftPos The position of the character in the code, counting from left to right
61 * @param rightPos The positionof the character in the code, counting from right to left
62 * @return The integer value of the character
63 * @throws CheckDigitException if character is not alphanumeric
64 */
65 protected int toInt(char character, int leftPos, int rightPos)
66 throws CheckDigitException {
67 int charValue = Character.getNumericValue(character);
68 if (charValue < 0 || charValue > 35) {
69 throw new CheckDigitException("Invalid Character[" +
70 leftPos + "] = '" + charValue + "'");
71 }
72 return charValue;
73 }
74
75 /**
76 * <p>Calculates the <i>weighted</i> value of a charcter in the
77 * code at a specified position.</p>
78 *
79 * <p>For Luhn (from right to left) <b>odd</b> digits are weighted
80 * with a factor of <b>one</b> and <b>even</b> digits with a factor
81 * of <b>two</b>. Weighted values > 9, have 9 subtracted</p>
82 *
83 * @param charValue The numeric value of the character.
84 * @param leftPos The position of the character in the code, counting from left to right
85 * @param rightPos The positionof the character in the code, counting from right to left
86 * @return The weighted value of the character.
87 */
88 protected int weightedValue(int charValue, int leftPos, int rightPos) {
89 int weight = POSITION_WEIGHT[rightPos % 2];
90 int weightedValue = (charValue * weight);
91 return ModulusCheckDigit.sumDigits(weightedValue);
92 }
93 }