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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>SEDOL</b> (UK Securities) Check Digit calculation/validation.
21   * <p>
22   * SEDOL Numbers are 7 character alphanumeric codes used
23   * to identify UK Securities (SEDOL stands for Stock Exchange Daily Official List).
24   * <p>
25   * Check digit calculation is based on <i>modulus 10</i> with digits being weighted
26   * based on their position, from left to right, as follows:
27   * <p>
28   * <pre><code>
29   *      position:  1  2  3  4  5  6  7
30   *     weighting:  1  3  1  7  3  9  1
31   * </code></pre>
32   * <p>
33   * See <a href="http://en.wikipedia.org/wiki/SEDOL">Wikipedia - SEDOL</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 SedolCheckDigit extends ModulusCheckDigit {
40  
41      private static final long serialVersionUID = -8976881621148878443L;
42  
43      /** Singleton SEDOL check digit instance */
44      public static final CheckDigit SEDOL_CHECK_DIGIT = new SedolCheckDigit();
45  
46      /** weighting given to digits depending on their right position */
47      private static final int[] POSITION_WEIGHT = new int[] {1, 3, 1, 7, 3, 9, 1};
48  
49      /**
50       * Construct a modulus 11 Check Digit routine for ISBN-10.
51       */
52      public SedolCheckDigit() {
53          super(10);
54      }
55  
56      /**
57       * Calculate the modulus for an SEDOL code.
58       *
59       * @param code The code to calculate the modulus for.
60       * @param includesCheckDigit Whether the code includes the Check Digit or not.
61       * @return The modulus value
62       * @throws CheckDigitException if an error occurs calculating the modulus
63       * for the specified code
64       */
65      protected int calculateModulus(String code, boolean includesCheckDigit) throws CheckDigitException {
66          if (code.length() > 7) {
67              throw new CheckDigitException("Invalid Code Length = " + code.length());
68          }
69          return super.calculateModulus(code, includesCheckDigit);
70      }
71  
72      /**
73       * Calculates the <i>weighted</i> value of a charcter in the
74       * code at a specified position.
75       *
76       * @param charValue The numeric value of the character.
77       * @param leftPos The position of the character in the code, counting from left to right
78       * @param rightPos The positionof the character in the code, counting from right to left
79       * @return The weighted value of the character.
80       */
81      protected int weightedValue(int charValue, int leftPos, int rightPos) {
82          return (charValue * POSITION_WEIGHT[leftPos - 1]);
83      }
84  
85      /**
86       * Convert a character at a specified position to an integer value.
87       *
88       * @param character The character to convert
89       * @param leftPos The position of the character in the code, counting from left to right
90       * @param rightPos The positionof the character in the code, counting from right to left
91       * @return The integer value of the character
92       * @throws CheckDigitException if character is not alphanumeric
93       */
94      protected int toInt(char character, int leftPos, int rightPos)
95              throws CheckDigitException {
96          int charValue = Character.getNumericValue(character);
97          if (charValue < 0 || charValue > 35) {
98              throw new CheckDigitException("Invalid Character[" +
99                      leftPos + "] = '" + charValue + "'");
100         }
101         return charValue;
102     }
103 
104 }