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Apache Struts 2 Documentation
Validation Annotation
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Added by Rainer Hermanns, last edited by Don Brown on Nov 14, 2006 (view change)

If you want to use annotation based validation, you have to annotate the class or interface with Validation Annotation.

## Usage

The Validation annotation must be applied at Type level.

## Parameters

Parameter | Required | Default | Notes
--- | --- | --- | ---
message | yes |  | field error message
key | no |  | i18n key from language specific properties file.
fieldName | no |  |
shortCircuit | no | false | If this validator should be used as shortCircuit.
type | yes | ValidatorType.FIELD | Enum value from ValidatorType. Either FIELD or SIMPLE can be used here.

## Examples

An Annotated Interface

- Mark the interface with @Validation()
- Apply standard or custom annoations at method level

    @Validation()
    public interface AnnotationDataAware {

        void setBarObj(Bar b);

        Bar getBarObj();

        @RequiredFieldValidator(message = "You must enter a value for data.")
        @RequiredStringValidator(message = "You must enter a value for data.")
        void setData(String data);

        String getData();
    }

An Annotated Class

    @Validation()
    public class SimpleAnnotationAction extends ActionSupport {

        @RequiredFieldValidator(type = ValidatorType.FIELD, message = "You must enter a value for bar.")
        @IntRangeFieldValidator(type = ValidatorType.FIELD, min = "6", max = "10", message = "bar must be between ${min} and ${max}, current value is ${bar}.")
        public void setBar(int bar) {
            this.bar = bar;
        }

        public int getBar() {
            return bar;
        }

        @Validations(
                requiredFields =
                        {@RequiredFieldValidator(type = ValidatorType.SIMPLE, fieldName = "customfield", message = "You must enter a value for field.")},
                requiredStrings =
                        {@RequiredStringValidator(type = ValidatorType.SIMPLE, fieldName = "stringisrequired", message = "You must enter a value for string.")},
                emails =
                        { @EmailValidator(type = ValidatorType.SIMPLE, fieldName = "emailaddress", message = "You must enter a value for email.")},
                urls =
                        { @UrlValidator(type = ValidatorType.SIMPLE, fieldName = "hreflocation", message = "You must enter a value for email.")},
                stringLengthFields =
                        {@StringLengthFieldValidator(type = ValidatorType.SIMPLE, trim = true, minLength="10" , maxLength = "12", fieldName = "needstringlength", message = "You must enter a stringlength.")},
                intRangeFields =
                        { @IntRangeFieldValidator(type = ValidatorType.SIMPLE, fieldName = "intfield", min = "6", max = "10", message = "bar must be between ${min} and ${max}, current value is ${bar}.")},
                dateRangeFields =
                        {@DateRangeFieldValidator(type = ValidatorType.SIMPLE, fieldName = "datefield", min = "-1", max = "99", message = "bar must be between ${min} and ${max}, current value is ${bar}.")},
                expressions = {
                    @ExpressionValidator(expression = "foo > 1", message = "Foo must be greater than Bar 1. Foo = ${foo}, Bar = ${bar}."),
                    @ExpressionValidator(expression = "foo > 2", message = "Foo must be greater than Bar 2. Foo = ${foo}, Bar = ${bar}."),
                    @ExpressionValidator(expression = "foo > 3", message = "Foo must be greater than Bar 3. Foo = ${foo}, Bar = ${bar}."),
                    @ExpressionValidator(expression = "foo > 4", message = "Foo must be greater than Bar 4. Foo = ${foo}, Bar = ${bar}."),
                    @ExpressionValidator(expression = "foo > 5", message = "Foo must be greater than Bar 5. Foo = ${foo}, Bar = ${bar}.")
        }
        )
        public String execute() throws Exception {
            return SUCCESS;
        }
    }