ISSNValidator.java
/*
* 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
*
* https://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;
import java.io.Serializable;
import org.apache.commons.validator.routines.checkdigit.CheckDigitException;
import org.apache.commons.validator.routines.checkdigit.EAN13CheckDigit;
import org.apache.commons.validator.routines.checkdigit.ISSNCheckDigit;
/**
* International Standard Serial Number (ISSN)
* is an eight-digit serial number used to
* uniquely identify a serial publication.
* <pre>
* The format is:
*
* ISSN dddd-dddC
* where:
* d = decimal digit (0-9)
* C = checksum (0-9 or X)
*
* The checksum is formed by adding the first 7 digits multiplied by
* the position in the entire number (counting from the right).
*
* For example, abcd-efg would be 8a + 7b + 6c + 5d + 4e +3f +2g.
* The check digit is modulus 11, where the value 10 is represented by 'X'
* For example:
* ISSN 0317-8471
* ISSN 1050-124X
*
* This class strips off the 'ISSN ' prefix if it is present before passing
* the remainder to the checksum routine.
*
* </pre>
* <p>
* Note: the {@link #isValid(String)} and {@link #validate(String)} methods strip off any leading
* or trailing spaces before doing the validation.
* To ensure that only a valid code (without 'ISSN ' prefix) is passed to a method,
* use the following code:
* </p>
* <pre>
* Object valid = validator.validate(input);
* if (valid != null) {
* some_method(valid.toString());
* }
* </pre>
* @since 1.5.0
*/
public class ISSNValidator implements Serializable {
private static final long serialVersionUID = 4319515687976420405L;
private static final String ISSN_REGEX = "(?:ISSN )?(\\d{4})-(\\d{3}[0-9X])$"; // We don't include the '-' in the code, so it is 8 chars
private static final int ISSN_LEN = 8;
private static final String ISSN_PREFIX = "977";
private static final String EAN_ISSN_REGEX = "^(977)(?:(\\d{10}))$";
private static final int EAN_ISSN_LEN = 13;
private static final CodeValidator VALIDATOR = new CodeValidator(ISSN_REGEX, ISSN_LEN, ISSNCheckDigit.ISSN_CHECK_DIGIT);
private static final CodeValidator EAN_VALIDATOR = new CodeValidator(EAN_ISSN_REGEX, EAN_ISSN_LEN, EAN13CheckDigit.EAN13_CHECK_DIGIT);
/** ISSN Code Validator. */
private static final ISSNValidator ISSN_VALIDATOR = new ISSNValidator();
/**
* Gets the singleton instance of the ISSN validator.
*
* @return A singleton instance of the ISSN validator.
*/
public static ISSNValidator getInstance() {
return ISSN_VALIDATOR;
}
/**
* Constructs a new instance.
*/
public ISSNValidator() {
// empty
}
/**
* Converts an ISSN code to an EAN-13 code.
* <p>
* This method requires a valid ISSN code.
* It may contain a leading 'ISSN ' prefix,
* as the input is passed through the {@link #validate(String)}
* method.
* </p>
*
* @param issn The ISSN code to convert
* @param suffix the two digit suffix, for example, "00"
* @return A converted EAN-13 code or {@code null}
* if the input ISSN code is not valid
*/
public String convertToEAN13(final String issn, final String suffix) {
if (suffix == null || !suffix.matches("\\d\\d")) {
throw new IllegalArgumentException("Suffix must be two digits: '" + suffix + "'");
}
final Object result = validate(issn);
if (result == null) {
return null;
}
// Calculate the new EAN-13 code
final String input = result.toString();
String ean13 = ISSN_PREFIX + input.substring(0, input.length() - 1) + suffix;
try {
final String checkDigit = EAN13CheckDigit.EAN13_CHECK_DIGIT.calculate(ean13);
ean13 += checkDigit;
return ean13;
} catch (final CheckDigitException e) { // Should not happen
throw new IllegalArgumentException("Check digit error for '" + ean13 + "' - " + e.getMessage());
}
}
/**
* Extracts an ISSN code from an ISSN-EAN-13 code.
* <p>
* This method requires a valid ISSN-EAN-13 code with NO formatting
* characters.
* That is a 13 digit EAN-13 code with the '977' prefix.
* </p>
*
* @param ean13 The ISSN code to convert
* @return A valid ISSN code or {@code null}
* if the input ISSN EAN-13 code is not valid
* @since 1.7
*/
public String extractFromEAN13(final String ean13) {
String input = ean13.trim();
if (input.length() != EAN_ISSN_LEN) {
throw new IllegalArgumentException("Invalid length " + input.length() + " for '" + input + "'");
}
if (!input.startsWith(ISSN_PREFIX)) {
throw new IllegalArgumentException("Prefix must be " + ISSN_PREFIX + " to contain an ISSN: '" + ean13 + "'");
}
final Object result = validateEan(input);
if (result == null) {
return null;
}
// Calculate the ISSN code
input = result.toString();
try {
//CHECKSTYLE:OFF: MagicNumber
final String issnBase = input.substring(3, 10); // TODO: how to derive these
//CHECKSTYLE:ON: MagicNumber
final String checkDigit = ISSNCheckDigit.ISSN_CHECK_DIGIT.calculate(issnBase);
return issnBase + checkDigit;
} catch (final CheckDigitException e) { // Should not happen
throw new IllegalArgumentException("Check digit error for '" + ean13 + "' - " + e.getMessage());
}
}
/**
* Tests whether the code is a valid ISSN code after any transformation
* by the validate routine.
*
* @param code The code to validate.
* @return {@code true} if a valid ISSN
* code, otherwise {@code false}.
*/
public boolean isValid(final String code) {
return VALIDATOR.isValid(code);
}
/**
* Checks the code is valid ISSN code.
* <p>
* If valid, this method returns the ISSN code with
* the 'ISSN ' prefix removed (if it was present)
* </p>
*
* @param code The code to validate.
* @return A valid ISSN code if valid, otherwise {@code null}.
*/
public Object validate(final String code) {
return VALIDATOR.validate(code);
}
/**
* Checks the code is a valid EAN code.
* <p>
* If valid, this method returns the EAN code
* </p>
*
* @param code The code to validate.
* @return A valid EAN code if valid, otherwise {@code null}.
* @since 1.7
*/
public Object validateEan(final String code) {
return EAN_VALIDATOR.validate(code);
}
}