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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   *
22   * <p>
23   * SEDOL Numbers are 7 character alphanumeric codes used
24   * to identify UK Securities (SEDOL stands for Stock Exchange Daily Official List).
25   * </p>
26   * <p>
27   * Check digit calculation is based on <i>modulus 10</i> with digits being weighted
28   * based on their position, from left to right, as follows:
29   * </p>
30   * <pre><code>
31   *      position:  1  2  3  4  5  6  7
32   *     weighting:  1  3  1  7  3  9  1
33   * </code></pre>
34   * <p>
35   * See <a href="http://en.wikipedia.org/wiki/SEDOL">Wikipedia - SEDOL</a>
36   * for more details.
37   * </p>
38   *
39   * @version $Revision: 1739356 $
40   * @since Validator 1.4
41   */
42  public final class SedolCheckDigit extends ModulusCheckDigit {
43  
44      private static final long serialVersionUID = -8976881621148878443L;
45  
46      private static final int MAX_ALPHANUMERIC_VALUE = 35; // Character.getNumericValue('Z')
47  
48      /** Singleton SEDOL check digit instance */
49      public static final CheckDigit SEDOL_CHECK_DIGIT = new SedolCheckDigit();
50  
51      /** weighting given to digits depending on their right position */
52      private static final int[] POSITION_WEIGHT = new int[] {1, 3, 1, 7, 3, 9, 1};
53  
54      /**
55       * Construct a modulus 11 Check Digit routine for ISBN-10.
56       */
57      public SedolCheckDigit() {
58          super(10); // CHECKSTYLE IGNORE MagicNumber
59      }
60  
61      /**
62       * Calculate the modulus for an SEDOL code.
63       *
64       * @param code The code to calculate the modulus for.
65       * @param includesCheckDigit Whether the code includes the Check Digit or not.
66       * @return The modulus value
67       * @throws CheckDigitException if an error occurs calculating the modulus
68       * for the specified code
69       */
70      @Override
71      protected int calculateModulus(String code, boolean includesCheckDigit) throws CheckDigitException {
72          if (code.length() > POSITION_WEIGHT.length) {
73              throw new CheckDigitException("Invalid Code Length = " + code.length());
74          }
75          return super.calculateModulus(code, includesCheckDigit);
76      }
77  
78      /**
79       * Calculates the <i>weighted</i> value of a charcter in the
80       * code at a specified position.
81       *
82       * @param charValue The numeric value of the character.
83       * @param leftPos The position of the character in the code, counting from left to right
84       * @param rightPos The positionof the character in the code, counting from right to left
85       * @return The weighted value of the character.
86       */
87      @Override
88      protected int weightedValue(int charValue, int leftPos, int rightPos) {
89          return charValue * POSITION_WEIGHT[leftPos - 1];
90      }
91  
92      /**
93       * Convert a character at a specified position to an integer value.
94       *
95       * @param character The character to convert
96       * @param leftPos The position of the character in the code, counting from left to right
97       * @param rightPos The positionof the character in the code, counting from right to left
98       * @return The integer value of the character
99       * @throws CheckDigitException if character is not alphanumeric
100      */
101     @Override
102     protected int toInt(char character, int leftPos, int rightPos)
103             throws CheckDigitException {
104         int charValue = Character.getNumericValue(character);
105         // the check digit is only allowed to reach 9
106         final int charMax = rightPos == 1 ? 9 : MAX_ALPHANUMERIC_VALUE; // CHECKSTYLE IGNORE MagicNumber
107         if (charValue < 0 || charValue > charMax) {
108             throw new CheckDigitException("Invalid Character[" +
109                     leftPos + "," + rightPos + "] = '" + charValue + "' out of range 0 to " + charMax);
110         }
111         return charValue;
112     }
113 
114 }