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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   * @since 1.4
40   */
41  public final class SedolCheckDigit extends ModulusCheckDigit {
42  
43      private static final long serialVersionUID = -8976881621148878443L;
44  
45      private static final int MAX_ALPHANUMERIC_VALUE = 35; // Character.getNumericValue('Z')
46  
47      /** Singleton SEDOL check digit instance */
48      public static final CheckDigit SEDOL_CHECK_DIGIT = new SedolCheckDigit();
49  
50      /** weighting given to digits depending on their right position */
51      private static final int[] POSITION_WEIGHT = {1, 3, 1, 7, 3, 9, 1};
52  
53      /**
54       * Constructs a modulus 10 Check Digit routine for ISBN-10.
55       */
56      public SedolCheckDigit() {
57          super();
58      }
59  
60      /**
61       * Calculate the modulus for an SEDOL code.
62       *
63       * @param code The code to calculate the modulus for.
64       * @param includesCheckDigit Whether the code includes the Check Digit or not.
65       * @return The modulus value
66       * @throws CheckDigitException if an error occurs calculating the modulus
67       * for the specified code
68       */
69      @Override
70      protected int calculateModulus(final String code, final boolean includesCheckDigit) throws CheckDigitException {
71          if (code.length() > POSITION_WEIGHT.length) {
72              throw new CheckDigitException("Invalid Code Length = " + code.length());
73          }
74          return super.calculateModulus(code, includesCheckDigit);
75      }
76  
77      /**
78       * Convert a character at a specified position to an integer value.
79       *
80       * @param character The character to convert
81       * @param leftPos The position of the character in the code, counting from left to right
82       * @param rightPos The positionof the character in the code, counting from right to left
83       * @return The integer value of the character
84       * @throws CheckDigitException if character is not alphanumeric
85       */
86      @Override
87      protected int toInt(final char character, final int leftPos, final int rightPos)
88              throws CheckDigitException {
89          final int charValue = Character.getNumericValue(character);
90          // the check digit is only allowed to reach 9
91          final int charMax = rightPos == 1 ? 9 : MAX_ALPHANUMERIC_VALUE; // CHECKSTYLE IGNORE MagicNumber
92          if (charValue < 0 || charValue > charMax) {
93              throw new CheckDigitException("Invalid Character[" +
94                      leftPos + "," + rightPos + "] = '" + charValue + "' out of range 0 to " + charMax);
95          }
96          return charValue;
97      }
98  
99      /**
100      * Calculates the <i>weighted</i> value of a character in the
101      * code at a specified position.
102      *
103      * @param charValue The numeric value of the character.
104      * @param leftPos The position of the character in the code, counting from left to right
105      * @param rightPos The positionof the character in the code, counting from right to left
106      * @return The weighted value of the character.
107      */
108     @Override
109     protected int weightedValue(final int charValue, final int leftPos, final int rightPos) {
110         return charValue * POSITION_WEIGHT[leftPos - 1];
111     }
112 
113 }