Package Documentation for org.apache.commons.validator.routines Package

This package contains independant validation routines.

# Table of Contents

- 1. Overview
- 2. Date and Time Validators
  - 2.1 Overview
  - 2.2 Validating a Date Value
  - 2.3 Formatting
  - 2.4 Time Zones
  - 2.5 Comparing Dates and Times
- 3. Numeric Validators
  - 3.1 Overview
  - 3.2 Validating a Numeric Value
  - 3.3 Formatting
  - 3.4 Comparing Numbers
  - 3.5 Currency Validation
  - 3.6 Percent Validation
- 4. Other Validators
  - 4.1 Overview
  - 4.2 Regular Expression validation
  - 4.3 Check Digit Validation/Calculation
  - 4.4 General Code Validation
  - 4.5 ISBN Validation
  - 4.6 IP Address Validation
  - 4.7 Email Address Validation
  - 4.8 URL Validation
  - 4.9 Domain Name Validation

# 1. Overview

Commons Validator serves two purposes:

- To provide standard, independent validation routines/functions.
- To provide a mini framework for Validation.

This package has been created, since version 1.3.0, in an attempt to clearly separate these two concerns and is the location for the standard, independent validation routines/functions in Commons Validator.

The contents of this package have no dependencies on the framework aspect of Commons Validator and can be used on their own.

# 2. Date and Time Validators

### 2.1 Overview

The date and time validators either validate according to a specified format or use a standard format for a specified `Locale`.

- Date Validator - validates dates converting to a `java.util.Date` type.
- Calendar Validator - validates dates converting to a `java.util.Calendar` type.
- Time Validator - validates times converting to a `java.util.Calendar` type.

### 2.2 Validating a Date Value

You can either use one of the `isValid()` methods to just determine if a date is valid, or use one of the `validate()` methods to validate a date and convert it to a `java.util.Date`...

          // Get the Date validator
          DateValidator validator = DateValidator.getInstance();

          // Validate/Convert the date
          Date fooDate = validator.validate(fooString, "dd/MM/yyyy");
          if (fooDate == null) {
              // error...not a valid date
              return;
          }

The following methods are provided to validate a date/time (return a boolean result):

- `isValid(value)`
- `isValid(value, pattern)`
- `isValid(value, Locale)`
- `isValid(value, pattern, Locale)`

The following methods are provided to validate a date/time and convert it to either a `java.util.Date` or `java.util.Calendar`:

- `validate(value)`
- `validate(value, pattern)`
- `validate(value, Locale)`
- `validate(value, pattern, Locale)`

### 2.3 Formatting

Formatting and validating are two sides of the same coin. Typically input values which are converted from Strings according to a specified format also have to be rendered for output in the same format. These validators provide the mechanism for formatting from date/time objects to Strings. The following methods are provided to format date/time values as Strings:

- `format(date/calendar)`
- `format(date/calendar, pattern)`
- `format(date/calendar, Locale)`
- `format(date/calendar, pattern, Locale)`

### 2.4 Time Zones

If the date being parsed relates to a different time zone than the system default, you can specify the `TimeZone` to use when validating/converting:

          // Get the GMT time zone
          TimeZone GMT = TimeZone.getInstance("GMT");

          // Validate/Convert the date using GMT
          Date fooDate = validator.validate(fooString, "dd/MM/yyyy", GMT);

The following Time Zone flavours of the Validation/Conversion methods are provided:

- `validate(value, TimeZone)`
- `validate(value, pattern, TimeZone)`
- `validate(value, Locale, TimeZone)`
- `validate(value, pattern, Locale, TimeZone)`

### 2.5 Comparing Dates and Times

As well as validating that a value is a valid date or time, these validators also provide date comparison functions. The `DateValidator` and `CalendarValidator` provide functions for comparing years, quarters, months, weeks and dates and the `TimeValidator` provides functions for comparing hours, minutes, seconds and milliseconds. For example, to check that a date is in the current month, you could use the `compareMonths()` method, which compares the year and month components of a date:

          // Check if the date is in the current month
          int compare = validator.compareMonths(fooDate, new Date(), null);
          if (compare == 0) {
              // do current month processing
              return;
          }

          // Check if the date is in the previous quarter
          compare = validator.compareQuarters(fooDate, new Date(), null);
          if (compare < 0) {
              // do previous quarter processing
              return;
          }

          // Check if the date is in the next year
          compare = validator.compareYears(fooDate, new Date(), null);
          if (compare > 0) {
              // do next year processing
              return;
          }

# 3 Numeric Validators

### 3.1 Overview

The numeric validators either validate according to a specified format or use a standard format for a specified `Locale` or use a custom format for a specified `Locale`.

- Byte Validator - validates numbers converting to a `java.lang.Byte` type.
- Short Validator - validates numbers converting to a `java.lang.Short` type.
- Integer Validator - validates numbers converting to a `java.lang.Integer` type.
- Long Validator - validates numbers converting to a `java.lang.Long` type.
- Float Validator - validates numbers converting to a `java.lang.Float` type.
- Double Validator - validates numbers converting to a `java.lang.Double` type.
- BigInteger Validator - validates numbers converting to a `java.math.BigInteger` type.
- BigDecimal Validator - validates numbers converting to a `java.math.BigDecimal` type.

### 3.2 Validating a Numeric Value

You can either use one of the `isValid()` methods to just determine if a number is valid, or use one of the `validate()` methods to validate a number and convert it to an appropriate type.

The following example validates an integer against a custom pattern for the German locale. Please note the format is specified using the standard symbols for `java.text.DecimalFormat` so although the decimal separator is indicated as a period (".") in the format, the validator will check using the German decimal separator - which is a comma (",").

          // Get the Integer validator
          IntegerValidator validator = IntegerValidator.getInstance();

          // Validate/Convert the number
          Integer fooInteger = validator.validate(fooString, "#,##0.00", Locale.GERMAN);
          if (fooInteger == null) {
              // error...not a valid Integer
              return;
          }

The following methods are provided to validate a number (return a boolean result):

- `isValid(value)`
- `isValid(value, pattern)`
- `isValid(value, Locale)`
- `isValid(value, pattern, Locale)`

The following methods are provided to validate a number and convert it one of the `java.lang.Number` implementations:

- `validate(value)`
- `validate(value, pattern)`
- `validate(value, Locale)`
- `validate(value, pattern, Locale)`

### 3.3 Formatting

Formatting and validating are two sides of the same coin. Typically input values which are converted from Strings according to a specified format also have to be rendered for output in the same format. These validators provide the mechanism for formatting from numeric objects to Strings. The following methods are provided to format numeric values as Strings:

- `format(number)`
- `format(number, pattern)`
- `format(number, Locale)`
- `format(number, pattern, Locale)`

### 3.4 Comparing Numbers

As well as validating that a value is a valid number, these validators also provide functions for validating the minimum, maximum and range of a value.

          // Check the number is between 25 and 75
          if (validator.isInRange(fooInteger, 25, 75) {
              // valid...in the specified range
              return;
          }

### 3.5 Currency Validation

A default Currency Validator implementation is provided, although all the numeric validators support currency validation. The default implementation converts currency amounts to a `java.math.BigDecimal` and additionally it provides lenient currency symbol validation. That is, currency amounts are valid with or without the currency symbol.

          BigDecimalValidator validator = CurrencyValidator.getInstance();

          BigDecimal fooAmount = validator.validate("$12,500.00", Locale.US);
          if (fooAmount == null) {
              // error...not a valid currency amount
              return;
          }

          // Check the amount is a minimum of $1,000
          if (validator.minValue(fooAmount, 1000) {
              // valid...in the specified range
              return;
          }

If, for example, you want to use the Integer Validator to validate a currency, then you can simply create a new instance with the appropriate format style. Note that the other validators do not support the lenient currency symbol validation.

          IntegerValidator validator =
              new IntegerValidator(true, IntegerValidator.CURRENCY_FORMAT);

          String pattern = "#,###" + '\u00A4' + '\u00A4';  // Use international symbol

          Integer fooAmount = validator.validate("10.100EUR", pattern, Locale.GERMAN);
          if (fooAmount == null) {
              // error...not a valid currency amount
              return;
          }

### 3.6 Percent Validation

A default Percent Validator implementation is provided, although the Float, Double and BigDecimal validators also support percent validation. The default implementation converts percent amounts to a `java.math.BigDecimal` and additionally it provides lenient percent symbol validation. That is, percent amounts are valid with or without the percent symbol.

          BigDecimalValidator validator = PercentValidator.getInstance();

          BigDecimal fooPercent = validator.validate("20%", Locale.US);
          if (fooPercent == null) {
              // error...not a valid percent
              return;
          }

          // Check the percent is between 10% and 90%
          if (validator.isInRange(fooPercent, 0.1, 0.9) {
              // valid...in the specified range
              return;
          }

If, for example, you want to use the Float Validator to validate a percent, then you can simply create a new instance with the appropriate format style. Note that the other validators do not support the lenient percent symbol validation.

          FloatValidator validator =
              new FloatValidator(true, FloatValidator.PERCENT_FORMAT);

          Float fooPercent = validator.validate("20%", "###%");
          if (fooPercent == null) {
              // error...not a valid percent
              return;
          }

Note: in theory the other numeric validators besides Float, Double and BigDecimal (i.e. Byte, Short, Integer, Long and BigInteger) also support percent validation. However, since they don't allow fractions they will only work with percentages greater than 100%.

# 4. Other Validators

### 4.1 Overview

This section lists other available validators.

- Regular Expressions - validates using Java 1.4+ regular expression support
- Check Digit - validates/calculates check digits (i.e. EAN/UPC, credit card, ISBN).
- Code Validation - provides generic code validation - format, minimum/maximum length and check digit.
- ISBN Validation - provides ISBN-10 and ISBN-13 validation.
- IP Address Validation - provides IPv4 address validation.
- Email Address Validation - provides email address validation according to RFC 822 standards.
- URL Validation - provides URL validation on scheme, domain, and authority.
- Domain Name Validation - provides domain name and IANA TLD validation.

### 4.2 Regular Expression Validation

Regular expression validation can be done either by using the static methods provied by RegexValidator or by creating a new instance, which caches and re-uses compiled Patterns.

- Method Flavours - three flavours of validation metods are provided:

- `isValid()` methods return true/false to indicate whether validation was successful.
- `validate()` methods return a `String` value of the matched groups aggregated together or `null` if invalid.
- `match()` methods return a `String` array of the matched groups or `null` if invalid.

- Case Sensitivity - matching can be done in either a case sensitive or case in-sensitive way.
- Multiple Expressions - instances of the RegexValidator can be created to either match against a single regular expression or set (String array) of regular expressions.

Below is an example of using one of the static methods to validate, matching in a case insensitive manner and returning a String of the matched groups (which doesn't include the hyphen).

          // set up the parameters
          boolean caseSensitive   = false;
          String regex            = "^([A-Z]*)(?:\\-)([A-Z]*)$";

          // validate - result should be a String of value "abcdef"
          String result = RegexValidator.validate("abc-def", regex, caseSensitive);

The following static methods are provided for regular expression validation:

- `isValid(value, regex)`
- `isValid(value, regex, caseSensitive)`
- `validate(value, regex)`
- `validate(value, regex, caseSensitive)`
- `match(value, regex)`
- `match(value, regex, caseSensitive)`

Below is an example of creating an instance of RegexValidator matching in a case insensitive manner against a set of regular expressions:

          // set up the parameters
          boolean caseSensitive = false;
          String regex1   = "^([A-Z]*)(?:\\-)([A-Z]*)*$"
          String regex2   = "^([A-Z]*)$";
          String[] regexs = new String[] {regex1, regex1};

          // Create the validator
          RegexValidator validator = new RegexValidator(regexs, caseSensitive);

          // Validate true/false
          boolean valid = validator.isValid("abc-def");

          // Validate and return a String
          String result = validator.validate("abc-def");

          // Validate and return a String[]
          String[] groups = validator.match("abc-def");

See the RegexValidator javadoc for a full list of the available constructors.

### 4.3 Check Digit validation/calculation

CheckDigit defines a new type for the calculation and validation of check digits with the following methods:

- `isValid(code)` - validates the check digit of a code, returning `true` or `false`.
- `calculate(code)` - calulates the check digit for a code returning the check digit character.

The following implementations are provided:

- ABANumberCheckDigit for ABA Number (or Routing Transit Number (RTN)) check digit calculation.
- CUSIPCheckDigit for CUSIP (North American Securities) check digit calculation.
- EAN13CheckDigit for EAN-13, UPC, ISBN-13 check digit calculation.
- ISBNCheckDigit for ISBN-10 and ISBN-13 check digit calculation.
- ISBN10CheckDigit for ISBN-10 check digit calculation.
- ISINCheckDigit for ISIN International Securities Identifying Number check digit calculation.
- LuhnCheckDigit for Luhn check digit calculation - used by credit cards.
- ModulusCheckDigit - abstract class for custom modulus check digit implementations.
- SedolCheckDigit for SEDOL (UK Securities) check digit calculation.
- VerhoeffCheckDigit for Verhoeff (Dihedral) check digit calculation.

The following examples show validating the check digit of a code:

          // Luhn check digit validation
          boolean valid = LuhnCheckDigit.INSTANCE.isValid(code);

          // EAN / UPC / ISBN-13 check digit validation
          boolean valid = EAN13CheckDigit.INSTANCE.isValid(code);

          // ISBN-10 check digit validation
          boolean valid = ISBNCheckDigit.ISBN10.isValid(code);
          boolean valid = ISBN10CheckDigit.INSTANCE.isValid(code);

          // ISBN-13 check digit validation
          boolean valid = ISBNCheckDigit.ISBN13.isValid(code);

          // ISBN-10 or ISBN-13 check digit validation
          boolean valid = ISBNCheckDigit.ISBN.isValid(code);

The following examples show calulating the check digit of a code:

          // Luhn check digit validation
          char checkdigit = LuhnCheckDigit.INSTANCE.calculate(code);

          // EAN / UPC / ISBN-13 check digit validation
          char checkdigit = EAN13CheckDigit.INSTANCE.calculate(code);

          // ISBN-10 check digit validation
          char checkdigit = ISBNCheckDigit.ISBN10.isValid(code);
          char checkdigit = ISBN10CheckDigit.INSTANCE.calculate(code);

          // ISBN-13 check digit validation
          char checkdigit = ISBNCheckDigit.ISBN13.calculate(code);

          // ISBN-10 or ISBN-13 check digit validation
          char checkdigit = ISBNCheckDigit.ISBN.calculate(code);

### 4.4 General Code validation

CodeValidator provides a generic implementation for validating codes. It performs the following validations on a code:

- Format - the format of the code is validated using a regular expression (see RegexValidator).
- Length - the minimum/maximum length of the code is checked - after being parsed by the regular expression - with which format characters can be removed with the use of non-capturing groups.
- Check Digit - a CheckDigit routine checks that code's check digit is valid.

For example to create a validator to validate EAN-13 codes (numeric, with a length of 13):

          // Create an EAN-13 code validator
          CodeValidator validator = new CodeValidator("^[0-9]*$", 13, EAN13CheckDigit.INSTANCE);

          // Validate an EAN-13 code
          if (!validator.isValid(code)) {
              ... // invalid
          }

### 4.5 ISBN validation

ISBNValidator provides ISBN-10 and ISBN-13 validation and can optionally convert ISBN-10 codes to ISBN-13.

- ISBN-10 - validates using a CodeValidator with the ISBN10CheckDigit routine.

- `isValidISBN10(value)` - returns a boolean
- `validateISBN10(value)` - returns a reformatted ISBN-10 code

- ISBN-13 - validates using a CodeValidator with the EAN13CheckDigit routine.

- `isValidISBN13(value)` - returns a boolean
- `validateISBN13(value)` - returns a reformatted ISBN-13 code

- ISBN-10 and ISBN-13 - validates codes are either valid ISBN-10 or valid ISBN-13 - optionally can convert ISBN-10 codes to ISBN-13.

- `isValid(value)` - returns a boolean
- `validate(value)` - returns a reformatted ISBN code (converts ISBN-10 to ISBN-13 if the convert option is `true`).

For example to validate

          // Validate an ISBN-10 or ISBN-13 code
          if (!ISBNValidator.getInstance().isValid(code)) {
              ... // invalid
          }

          // Validate an ISBN-10 or ISBN-13 code (converting to ISBN-13)
          String code = ISBNValidator.getInstance().validate(code);

          // Validate an ISBN-10 or ISBN-13 code (not converting)
          String code = ISBNValidator.getInstance(false).validate(code);

### 4.6 IP Address Validation

InetAddressValidator provides IPv4 address validation.

For example:

          // Get an InetAddressValidator
          InetAddressValidator validator = InetAddressValidator.getInstance();

          // Validate an IPv4 address
          if (!validator.isValid(candidateInetAddress)) {
              ... // invalid
          }

### 4.7 Email Address Validation

EmailValidator provides email address validation according to RFC 822 standards.

For example:

          // Get an EmailValidator
          EmailValidator validator = EmailValidator.getInstance();

          // Validate an email address
          boolean isAddressValid = validator.isValid("user@apache.org");

          // Validate a variable containing an email address
          if (!validator.isValid(addressFromUserForm)) {
              webController.sendRedirect(ERROR_REDIRECT, "Email address isn't valid");
              // etc.
          }

### 4.8 URL Validation

UrlValidator provides URL validation by checking the scheme, authority, path, query, and fragment in turn. Clients may specify valid schemes to be used in validating in addition to or instead of the default values (HTTP, HTTPS, FTP). The UrlValidator also supports options that change the parsing rules; for example, the ALLOW_2_SLASHES option instructs the Validator to allow consecutive slash characters in the path component, which is considered an error by default. For more information on the available options, see the UrlValidator documentation.

For example:

          // Get an UrlValidator
          UrlValidator defaultValidator = new UrlValidator(); // default schemes
          if (defaultValidator.isValid("http://www.apache.org")) {
              ... // valid
          }
          if (!defaultValidator.isValid("http//www.oops.com")) {
              ... // invalid
          }

          // Get an UrlValidator with custom schemes
          String[] customSchemes = { "sftp", "scp", "https" };
          UrlValidator customValidator = new UrlValidator(customSchemes);
          if (!customValidator.isValid("http://www.apache.org")) {
              ... // invalid due to insecure protocol
          }

          // Get an UrlValidator that allows double slashes in the path
          UrlValidator doubleSlashValidator = new UrlValidator(UrlValidator.ALLOW_2_SLASHES);
          if (doubleSlashValidator.isValid("http://www.apache.org//projects")) {
              ... // valid only in this Validator instance
          }

### 4.9 Domain Name Validation

DomainValidator provides validation of Internet domain names as specified by RFC1034/RFC1123 and according to the IANA-recognized list of top-level domains (TLDs). Clients may validate an entire domain name, a TLD of any category, or a TLD within a specific category.

For example:

          // Get a DomainValidator
          DomainValidator validator = DomainValidator.getInstance();

          // Validate a domain name
          if (validator.isValid("www.apache.org")) {
              ... // valid
          }
          if (!validator.isValid("www.apache.wrong")) {
              ... // invalid
          }

          // Validate a TLD
          if (validator.isValidTld(".com")) {
              ... // valid
          }
          if (validator.isValidTld("org")) {
              ... // valid, the leading dot is optional
          }
          if (validator.isValidTld(".us")) {
              ... // valid, country code TLDs are also accepted
          }

          // Validate TLDs in categories
          if (validator.isValidGenericTld(".name")) {
              ... // valid
          }
          if (!validator.isValidGenericTld(".uk")) {
              ... // invalid, .uk is a country code TLD
          }
          if (!validator.isValidCountryCodeTld(".info")) {
              ... // invalid, .info is a generic TLD
          }