Domain Class Validation

• #Example
• #Reference
• #blank
• #creditCard
• #email
• #password
• #inList
• -#length-
• #matches
• #max
• -#maxLength-
• #maxSize
• #min
• -#minLength-
• #minSize
• #notEqual
• #nullable
• #range
• #scale
• #size
• #unique
• #url
• #validator

Example

class User {
   String login
   String password
   static constraints = {
          login(size:5..15,blank:false,unique:true)
          password(size:5..15,blank:false)
   }
}

For example, referring to the above class, the error message might be defined as: _user.login.blank=Please enter a login_

{_}Since 0.5. You could use common pattern "className.propertyName.constraintName.error" for all constraints, example: "user.login.blank.error=Please enter a login"._

Validation Constraint Reference

blank

Usage: set to false if a string value cannot be blank
Note: an empty form field will appear in the request parameters as an empty string, not as null. Keep this in mind when setting domain fields directly form request parameters
Remember, there are some blank values that are not null, for example an empty String or a Tab. For null validations see #nullable constraint.
Example:

login(blank:false)

creditCard

Usage: set to true if a string should be a credit card number Example:

cardNumber(creditCard:true)

email

Usage: set to true if a string value is an email address Example:

contactEmail(email:true)

password

Usage: set to true if a string value is a password Example:

password(password:true)

inList

Usage: constrains a value so that it must be contained within the given list Example 1:

name(inList:["Joe", "Fred", "Bob"] )

Example 2:

name(inList:[1 as Short, 2 as Short, 3 as Short] ) // Short could be switched to Double etc

Error message code: className.propertyName.not.inList

This constraint influences schema generation.

length

Deprecated in 0.4. Removed in 0.5. Use #size instead.

Usage: Uses a Groovy range to restrict the length of a string or array Example:

login(length:5..15)

This constraint influences schema generation.

matches

Usage: Applies a regular expression against a string value Example:

login(matches:"[a-zA-Z]+")

max

Usage: sets the maximum value of a class that implements java.lang.Comparable. The same type needs to be used as the property itself. Example:

age(max:new Date())
price(max:999F)

This constraint influences schema generation.

maxLength

Deprecated in 0.4. Removed in 0.5. Use #maxSize instead.

Usage: sets the maximum length of a string or array property Example:

login(maxLength:5)

This constraint influences schema generation.

maxSize

Usage: sets the maximum size of a collection or number property

Deprecated in 0.5 for number properties. Use #max instead.

Example:

children(maxSize:25)

This constraint influences schema generation.

min

Usage: sets the minimum value of a class that implements java.lang.Comparable. The same type needs to be used as the property itself. Example:

age(min:new Date())
price(min:0F) // or price(min:0.0 as Double)

This constraint influences schema generation.

minLength

Deprecated in 0.4. Removed in 0.5. Use #minSize instead.

Usage: sets the minimum length of a string or array property Example:

login(minLength:5)

This constraint influences schema generation.

minSize

Usage: sets the minimum size of a collection or number property

Deprecated in 0.5 for number properties. Use #min instead.

Example:

children(minSize:5)

This constraint influences schema generation.

notEqual

Usage: validates that a property is not equal to the specified value Example:

login(notEqual:"Bob")

nullable

Usage: set to false if the property value cannot be null
Note: an empty form field will appear in the request parameters as an empty string, not as null. Keep this in mind when setting domain fields directly form request parameters
Remember, there are some blank values that are not null, for example an empty String or a Tab. For blank validations see #blank constraint.
Example:

age(nullable:true)

range

Usage: Uses a Groovy range to ensure that a property's value occurs within a specified range Example:

age(range:minAge..maxAge)

This constraint influences schema generation.

scale

_Since: 0.4_ Usage: Set to the desired scale for floating point numbers (i.e., the number of digits to the right of the decimal point). This constraint is applicable for properties of the following types: java.lang.Float, java.lang.Double, and java.math.BigDecimal (and its subclasses). When validation is invoked, this constraint determines if the number includes more nonzero decimal places than the scale permits. If so, it automatically rounds the number to the maximum number of decimal places allowed by the scale. This constraint does not generate validation error messages. Example:

salary(scale:2)

This constraint influences schema generation.

size

Usage: Uses a Groovy range to restrict the size of a collection or number or the length of a String

Deprecated in 0.5 for number properties. Use #range instead.

Example:

children(size:5..15)

This constraint influences schema generation.

unique

Usage: set to true if the property must be unique (this is a persistent call and will query the database) Example:

login(unique:true)

Example:

group(unique:'department')

Another example:

login(unique:['group','department'])

Error message code: className.propertyName.unique

url

Usage: set to true if a string value is a URL address Example:

homePage(url:true)

validator

Usage: set to a Closure to use custom validation. A single or no parameter Closure receives the value, a two-parameter Closure receives the value and object reference.

Since 0.5.5 a three-parameter Closure receives the value, object reference and the errors object.

The closure can return:

• null or true to indicate that the value is valid
• false to indicate an invalid value and use the default message code
• a string to indicate the error code to append to the "classname.propertName." string to display an error
• a list containing a string as above, and then any number of arguments following it, which can be used as formatted message arguments indexed at 3 onwards. See grails-app/i18n/message.properties to see how the default error message codes use the arguments.

Examples:

even( validator: {
   return (it % 2) == 0
})
password1( validator: {
   val, obj ->
      obj.properties['password2'] == val
})
magicNumber( validator:
   someClosureWithTwoParameters)
// This one assumes you have an error message defined like:
// classname.propertyName.custom.error=My error shows arguments {3} and {4} for value {0}
otherProperty( validator: { return ['custom.error', arg1, arg2] } )
// The following example does not use custom validation.
// A custom message may be defined in messages.properties:
// user.login.blank=Please enter a login
// which will be used instead of default.blank.message
class User {
    String login
    static constraints = {
        login(blank:false)
    }
}
// In the following example, custom validation is used:
// user.login.validator.invalid=Please enter a login
class User {
   String login
    static constraints = {
        login(validator: {
            return (it.length != 0)
    	})
    }
}
// The following might define the error message as:
// user.login.invalid.bountyhunter=Invalid bounty hunter ({2}) tried to log in.  (Class name = {1}.  Property name = {0})
class User {
    String login
    static constraints = {
        login(validator: {
            if (!it.startsWith('boba')) return ['invalid.bountyhunter']
        })
    }
}

For custom error messages, you can also return a custom value to be displayed in the error message. This is usually parameter number 3.

For instance, in messages.properties: source.reportName.invalid=For source type {3}, report name must be specified.

And in the custom validator:

reportName(maxSize:255, nullable: true, validator: { val, obj ->
  if(obj.reportName == null && (obj.sourceName == 'Buddecom Report')){
      return ['source.reportName.invalid', obj.sourceName]
  }	        
})