public interface CheckDigit
The logic for validating check digits has previously been
embedded within the logic for specific code validation, which
includes other validations such as verifying the format
or length of a code.
CheckDigit provides for separating out
the check digit calculation logic enabling it to be more easily
tested and reused.
Although Commons Validator is primarily concerned with validation,
CheckDigit also defines behavior for calculating/generating check
digits, since it makes sense that users will want to (re-)use the
same logic for both. The
makes specific use of this feature by providing the facility to validate ISBN-10 codes
and then convert them to the new ISBN-13 standard.
CheckDigit is used by the new generic @link CodeValidator} implementation.
String calculate(String code) throws CheckDigitException
code- The code to calculate the Check Digit for. The string must not include the check digit
CheckDigitException- if an error occurs.
boolean isValid(String code)
code- The code to validate, the string must include the check digit.
trueif the check digit is valid, otherwise
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