This package contains independant validation routines.

Table of Contents

1. Overview

Commons Validator serves two purposes:

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, independant 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.

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):

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

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:

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

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.

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):

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

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:

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.

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.

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:

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:

The following implementations are provided:

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:

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.

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
      }