001/* 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * https://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017package org.apache.commons.validator.routines.checkdigit; 018 019import org.apache.commons.validator.GenericValidator; 020import org.apache.commons.validator.routines.CodeValidator; 021 022/** 023 * Modulus 11 <strong>EC number</strong> Check Digit calculation/validation. 024 * 025 * <p> 026 * The European Community number (EC number) is a unique seven-digit identifier 027 * that is assigned to chemical substances. 028 * For example, the EC number of arsenic is 231-148-6: 029 * </p> 030 * 031 * <p> 032 * Check digit calculation is based on <em>modulus 11</em> with digits being weighted 033 * based on their position (from left to right). 034 * </p> 035 * 036 * <p> 037 * For further information see 038 * <a href="https://en.wikipedia.org/wiki/European_Community_number">Wikipedia - EC number</a>. 039 * </p> 040 * 041 * @since 1.9.0 042 */ 043public final class ECNumberCheckDigit extends ModulusCheckDigit { 044 045 private static final long serialVersionUID = 7265356024784308367L; 046 047 /** Singleton Check Digit instance */ 048 private static final ECNumberCheckDigit INSTANCE = new ECNumberCheckDigit(); 049 050 /** 051 * EC number consists of 3 groups of numbers separated dashes (-). 052 * Example: dexamethasone is 200-003-9 053 */ 054 private static final String GROUP = "(\\d{3})"; 055 056 private static final String DASH = "(?:\\-)"; 057 static final String EC_REGEX = "^(?:" + GROUP + DASH + GROUP + DASH + "(\\d))$"; 058 private static final int EC_LEN = 7; 059 060 static final CodeValidator REGEX_VALIDATOR = new CodeValidator(EC_REGEX, EC_LEN, null); 061 /** 062 * Gets the singleton instance of this validator. 063 * @return A singleton instance of the EC Number validator. 064 */ 065 public static CheckDigit getInstance() { 066 return INSTANCE; 067 } 068 069 /** 070 * Constructs a modulus 11 Check Digit routine. 071 */ 072 private ECNumberCheckDigit() { 073 super(MODULUS_11); 074 } 075 076 /** 077 * {@inheritDoc} 078 */ 079 @Override 080 public String calculate(final String code) throws CheckDigitException { 081 if (GenericValidator.isBlankOrNull(code)) { 082 throw new CheckDigitException("Code is missing"); 083 } 084 final int modulusResult = INSTANCE.calculateModulus(code, false); 085 return toCheckDigit(modulusResult); 086 } 087 088 /** 089 * {@inheritDoc} 090 */ 091 @Override 092 public boolean isValid(final String code) { 093 if (GenericValidator.isBlankOrNull(code)) { 094 return false; 095 } 096 final Object cde = REGEX_VALIDATOR.validate(code); 097 if (!(cde instanceof String)) { 098 return false; 099 } 100 try { 101 final int modulusResult = INSTANCE.calculateModulus((String) cde, true); 102 return modulusResult == Character.getNumericValue(code.charAt(code.length() - 1)); 103 } catch (final CheckDigitException ex) { 104 return false; 105 } 106 } 107 108 /** 109 * Calculates the <em>weighted</em> value of a character in the 110 * code at a specified position. 111 * 112 * <p>For EC number digits are weighted by their position from left to right.</p> 113 * 114 * @param charValue The numeric value of the character. 115 * @param leftPos The position of the character in the code, counting from left to right 116 * @param rightPos The position of the character in the code, counting from right to left 117 * @return The weighted value of the character. 118 */ 119 @Override 120 protected int weightedValue(final int charValue, final int leftPos, final int rightPos) { 121 return leftPos >= EC_LEN ? 0 : charValue * leftPos; 122 } 123 124}