org.apache.commons.validator.routines.checkdigit.IBANCheckDigit Maven / Gradle / Ivy
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/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.commons.validator.routines.checkdigit;
import java.io.Serializable;
/**
* IBAN (International Bank Account Number) Check Digit calculation/validation.
*
* This routine is based on the ISO 7064 Mod 97,10 check digit calculation routine.
*
* The two check digit characters in a IBAN number are the third and fourth characters
* in the code. For check digit calculation/validation the first four characters are moved
* to the end of the code.
* So CCDDnnnnnnn
becomes nnnnnnnCCDD
(where
* CC
is the country code and DD
is the check digit). For
* check digit calculation the check digit value should be set to zero (i.e.
* CC00nnnnnnn
in this example.
*
* Note: the class does not check the format of the IBAN number, only the check digits.
*
* For further information see
* Wikipedia -
* IBAN number.
*
* @version $Revision: 1739357 $
* @since Validator 1.4
*/
public final class IBANCheckDigit implements CheckDigit, Serializable {
private static final int MIN_CODE_LEN = 5;
private static final long serialVersionUID = -3600191725934382801L;
private static final int MAX_ALPHANUMERIC_VALUE = 35; // Character.getNumericValue('Z')
/** Singleton IBAN Number Check Digit instance */
public static final CheckDigit IBAN_CHECK_DIGIT = new IBANCheckDigit();
private static final long MAX = 999999999;
private static final long MODULUS = 97;
/**
* Construct Check Digit routine for IBAN Numbers.
*/
public IBANCheckDigit() {
}
/**
* Validate the check digit of an IBAN code.
*
* @param code The code to validate
* @return true
if the check digit is valid, otherwise
* false
*/
@Override
public boolean isValid(String code) {
if (code == null || code.length() < MIN_CODE_LEN) {
return false;
}
String check = code.substring(2,4); // CHECKSTYLE IGNORE MagicNumber
if ("00".equals(check) || "01".equals(check) || "99".equals(check)) {
return false;
}
try {
int modulusResult = calculateModulus(code);
return (modulusResult == 1);
} catch (CheckDigitException ex) {
return false;
}
}
/**
* Calculate the Check Digit for an IBAN code.
*
* Note: The check digit is the third and fourth
* characters and is set to the value "00
".
*
* @param code The code to calculate the Check Digit for
* @return The calculated Check Digit as 2 numeric decimal characters, e.g. "42"
* @throws CheckDigitException if an error occurs calculating
* the check digit for the specified code
*/
@Override
public String calculate(String code) throws CheckDigitException {
if (code == null || code.length() < MIN_CODE_LEN) {
throw new CheckDigitException("Invalid Code length=" +
(code == null ? 0 : code.length()));
}
code = code.substring(0, 2) + "00" + code.substring(4); // CHECKSTYLE IGNORE MagicNumber
int modulusResult = calculateModulus(code);
int charValue = (98 - modulusResult); // CHECKSTYLE IGNORE MagicNumber
String checkDigit = Integer.toString(charValue);
return (charValue > 9 ? checkDigit : "0" + checkDigit); // CHECKSTYLE IGNORE MagicNumber
}
/**
* Calculate the modulus for a code.
*
* @param code The code to calculate the modulus for.
* @return The modulus value
* @throws CheckDigitException if an error occurs calculating the modulus
* for the specified code
*/
private int calculateModulus(String code) throws CheckDigitException {
String reformattedCode = code.substring(4) + code.substring(0, 4); // CHECKSTYLE IGNORE MagicNumber
long total = 0;
for (int i = 0; i < reformattedCode.length(); i++) {
int charValue = Character.getNumericValue(reformattedCode.charAt(i));
if (charValue < 0 || charValue > MAX_ALPHANUMERIC_VALUE) {
throw new CheckDigitException("Invalid Character[" +
i + "] = '" + charValue + "'");
}
total = (charValue > 9 ? total * 100 : total * 10) + charValue; // CHECKSTYLE IGNORE MagicNumber
if (total > MAX) {
total = total % MODULUS;
}
}
return (int)(total % MODULUS);
}
}