Package jakarta.validation
Annotation Type Constraint
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@Documented @Target(ANNOTATION_TYPE) @Retention(RUNTIME) public @interface Constraint
Marks an annotation as being a Jakarta Bean Validation constraint.A given constraint annotation must be annotated by a
@Constraint
annotation which refers to its list of constraint validation implementations.Each constraint annotation must host the following attributes:
String message() default [...];
which should default to an error message key made of the fully-qualified class name of the constraint followed by.message
. For example"{com.acme.constraints.NotSafe.message}"
Class<?>[] groups() default {};
for user to customize the targeted groupsClass<? extends Payload>[] payload() default {};
for extensibility purposes
When building a constraint that is both generic and cross-parameter, the constraint annotation must host the
validationAppliesTo()
property. A constraint is generic if it targets the annotated element and is cross-parameter if it targets the array of parameters of a method or constructor.ConstraintTarget validationAppliesTo() default ConstraintTarget.IMPLICIT;
This property allows the constraint user to choose whether the constraint targets the return type of the executable or its array of parameters. A constraint is both generic and cross-parameter if- two kinds of
ConstraintValidator
s are attached to the constraint, one targetingValidationTarget.ANNOTATED_ELEMENT
and one targetingValidationTarget.PARAMETERS
, - or if a
ConstraintValidator
targets bothANNOTATED_ELEMENT
andPARAMETERS
.
SupportedValidationTarget
for more info.Here is an example of constraint definition:
@Documented @Constraint(validatedBy = OrderNumberValidator.class) @Target({ METHOD, FIELD, ANNOTATION_TYPE, CONSTRUCTOR, PARAMETER, TYPE_USE }) @Retention(RUNTIME) public @interface OrderNumber { String message() default "{com.acme.constraint.OrderNumber.message}"; Class<?>[] groups() default {}; Class<? extends Payload>[] payload() default {}; }
- Author:
- Emmanuel Bernard, Gavin King, Hardy Ferentschik
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Required Element Summary
Required Elements Modifier and Type Required Element Description Class<? extends ConstraintValidator<?,?>>[]
validatedBy
ConstraintValidator
classes implementing the constraint.
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Element Detail
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validatedBy
Class<? extends ConstraintValidator<?,?>>[] validatedBy
ConstraintValidator
classes implementing the constraint. The given classes must reference distinct target types for a givenValidationTarget
. If twoConstraintValidator
s refer to the same type, an exception will occur.At most one
ConstraintValidator
targeting the array of parameters of methods or constructors (aka cross-parameter) is accepted. If two or more are present, an exception will occur.- Returns:
- array of
ConstraintValidator
classes implementing the constraint
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