# Class CodeValidator

java.lang.Object
org.apache.commons.validator.routines.CodeValidator

All Implemented Interfaces:
  `Serializable`

public final class CodeValidator extends Object implements Serializable
Generic Code Validation providing format, minimum/maximum length and `CheckDigit` validations.

Performs the following validations on a code:

- if the code is null, return null/false as appropriate
- trim the input. If the resulting code is empty, return null/false as appropriate
- Check the format of the code using a regular expression. (if specified)
- Check the minimum and maximum length (if specified) of the parsed code (that is, parsed by the regular expression).
- Performs `CheckDigit` validation on the parsed code (if specified).
- The `validate(String)` method returns the trimmed, parsed input (or null if validation failed)

Note The `isValid(String)` method will return true if the input passes validation. Since this includes trimming as well as potentially dropping parts of the input, it is possible for a String to pass validation but fail the checkdigit test if passed directly to it (the check digit routines generally don't trim input nor do they generally check the format/length). To be sure that you are passing valid input to a method use `validate(String)` as follows:

    Object valid = validator.validate(input);
    if (valid != null) {
       some_method(valid.toString());
    }

Configure the validator with the appropriate regular expression, minimum/maximum length and `CheckDigit` validator and then call one of the two validation methods provided:

- `boolean isValid(code)`
- `String validate(code)`

Codes often include format characters - such as hyphens - to make them more easily human-readable. These can be removed prior to length and check digit validation by specifying them as a non-capturing group in the regular expression (that is, use the `(?: )` notation).
Or just avoid using parentheses except for the parts you want to capture

Since:
  1.4
See Also:
  - Serialized Form

- ## Constructor Summary

  Constructors
  Constructor
  Description
  `CodeValidator(String regex, int minLength, int maxLength, CheckDigit checkdigit)`
  Constructs a code validator with a specified regular expression, minimum/maximum length and `CheckDigit` validation.
  `CodeValidator(String regex, int length, CheckDigit checkdigit)`
  Constructs a code validator with a specified regular expression, length and `CheckDigit`.
  `CodeValidator(String regex, CheckDigit checkdigit)`
  Constructs a code validator with a specified regular expression and `CheckDigit`.
  `CodeValidator(RegexValidator regexValidator, int minLength, int maxLength, CheckDigit checkdigit)`
  Constructs a code validator with a specified regular expression validator, minimum/maximum length and `CheckDigit` validation.
  `CodeValidator(RegexValidator regexValidator, int length, CheckDigit checkdigit)`
  Constructs a code validator with a specified regular expression, validator, length and `CheckDigit` validation.
  `CodeValidator(RegexValidator regexValidator, CheckDigit checkdigit)`
  Constructs a code validator with a specified regular expression, validator and `CheckDigit` validation.

- ## Method Summary

  Modifier and Type
  Method
  Description
  `CheckDigit`
  `getCheckDigit()`
  Gets the check digit validation routine.
  `int`
  `getMaxLength()`
  Gets the maximum length of the code.
  `int`
  `getMinLength()`
  Gets the minimum length of the code.
  `RegexValidator`
  `getRegexValidator()`
  Gets the regular expression validator.
  `boolean`
  `isValid(String input)`
  Validates the code returning either `true` or `false`.
  `Object`
  `validate(String input)`
  Validates the code returning either the valid code or `null` if invalid.

  ### Methods inherited from class Object

  `clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

- ## Constructor Details

  - ### CodeValidator

    public CodeValidator(RegexValidator regexValidator, CheckDigit checkdigit)
    Constructs a code validator with a specified regular expression, validator and `CheckDigit` validation.
    Parameters:
      `regexValidator` - The format regular expression validator.
      `checkdigit` - The check digit validation routine.

  - ### CodeValidator

    public CodeValidator(RegexValidator regexValidator, int length, CheckDigit checkdigit)
    Constructs a code validator with a specified regular expression, validator, length and `CheckDigit` validation.
    Parameters:
      `regexValidator` - The format regular expression validator.
      `length` - The length of the code. (sets the minimum/maximum to the same value).
      `checkdigit` - The check digit validation routine.

  - ### CodeValidator

    public CodeValidator(RegexValidator regexValidator, int minLength, int maxLength, CheckDigit checkdigit)
    Constructs a code validator with a specified regular expression validator, minimum/maximum length and `CheckDigit` validation.
    Parameters:
      `regexValidator` - The format regular expression validator.
      `minLength` - The minimum length of the code.
      `maxLength` - The maximum length of the code.
      `checkdigit` - The check digit validation routine.

  - ### CodeValidator

    public CodeValidator(String regex, CheckDigit checkdigit)
    Constructs a code validator with a specified regular expression and `CheckDigit`. The RegexValidator validator is created to be case-sensitive
    Parameters:
      `regex` - The format regular expression.
      `checkdigit` - The check digit validation routine.

  - ### CodeValidator

    public CodeValidator(String regex, int length, CheckDigit checkdigit)
    Constructs a code validator with a specified regular expression, length and `CheckDigit`. The RegexValidator validator is created to be case-sensitive
    Parameters:
      `regex` - The format regular expression.
      `length` - The length of the code (sets the minimum/maximum to the same).
      `checkdigit` - The check digit validation routine.

  - ### CodeValidator

    public CodeValidator(String regex, int minLength, int maxLength, CheckDigit checkdigit)
    Constructs a code validator with a specified regular expression, minimum/maximum length and `CheckDigit` validation. The RegexValidator validator is created to be case-sensitive
    Parameters:
      `regex` - The regular expression.
      `minLength` - The minimum length of the code.
      `maxLength` - The maximum length of the code.
      `checkdigit` - The check digit validation routine.

- ## Method Details

  - ### getCheckDigit

    public CheckDigit getCheckDigit()
    Gets the check digit validation routine.

    N.B. Optional, if not set no Check Digit validation will be performed on the code.

    Returns:
      The check digit validation routine

  - ### getMaxLength

    public int getMaxLength()
    Gets the maximum length of the code.

    N.B. Optional, if less than zero the maximum length will not be checked.

    Returns:
      The maximum length of the code or `-1` if the code has no maximum length

  - ### getMinLength

    public int getMinLength()
    Gets the minimum length of the code.

    N.B. Optional, if less than zero the minimum length will not be checked.

    Returns:
      The minimum length of the code or `-1` if the code has no minimum length.

  - ### getRegexValidator

    public RegexValidator getRegexValidator()
    Gets the regular expression validator.

    N.B. Optional, if not set no regular expression validation will be performed on the code.

    Returns:
      The regular expression validator.

  - ### isValid

    public boolean isValid(String input)
    Validates the code returning either `true` or `false`.

    This calls `validate(String)` and returns false if the return value is null, true otherwise.

    Note that `validate(String)` trims the input and if there is a `RegexValidator` it may also change the input as part of the validation.

    Parameters:
      `input` - The code to validate.
    Returns:
      `true` if valid, otherwise `false`.

  - ### validate

    public Object validate(String input)
    Validates the code returning either the valid code or `null` if invalid.

    Note that this method trims the input and if there is a `RegexValidator` it may also change the input as part of the validation.

    Parameters:
      `input` - The code to validate.
    Returns:
      The code if valid, otherwise `null` if invalid.