CheckDigit (Commons Validator (Version 1.5.0-SNAPSHOT))

All Known Implementing Classes:

ABANumberCheckDigit, CUSIPCheckDigit, EAN13CheckDigit, IBANCheckDigit, ISBN10CheckDigit, ISBNCheckDigit, ISINCheckDigit, ISSNCheckDigit, LuhnCheckDigit, ModulusCheckDigit, SedolCheckDigit, VerhoeffCheckDigit
```
public interface CheckDigit
```
Check Digit calculation and validation.
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 behaviour for calculating/generating check digits, since it makes sense that users will want to (re-)use the same logic for both. The ISBNValidator 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.

Implementations
See the Package Summary for a full list of implementations provided within Commons Validator.

Since:

Validator 1.4

Version:

$Revision: 1649287 $

See Also:

CodeValidator

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`java.lang.String`	`calculate(java.lang.String code)`	Calculates the Check Digit for a code.
`boolean`	`isValid(java.lang.String code)`	Validates the check digit for the code.

- Method Detail
  - calculate
```
java.lang.String calculate(java.lang.String code)
                    throws CheckDigitException
```
    Calculates the Check Digit for a code.
    
    Parameters:
    
    code - The code to calculate the Check Digit for. The string must not include the check digit
    
    Returns:
    
    The calculated Check Digit
    
    Throws:
    
    CheckDigitException - if an error occurs.
  - isValid
```
boolean isValid(java.lang.String code)
```
    Validates the check digit for the code.
    
    Parameters:
    
    code - The code to validate, the string must include the check digit.
    
    Returns:
    
    true if the check digit is valid, otherwise false.