Package org.summerboot.jexpress.util.annotation

Annotation Interface LimitNonNullGroup

@Repeatable(List.class)
@Documented
@Constraint(validatedBy=LimitNonNullGroupValidator.class)
@Target(TYPE)
@Retention(RUNTIME)
public @interface LimitNonNullGroup

Validation annotation to ensure that exactly a specified number of fields are non-null.

This is useful in scenarios where only one (or a specific number of) mutually exclusive fields should be provided in a request or form, for example: providing exactly one contact method.

Usage Example:

 @LimitNonNullGroup(
     fields = { "field1", "field2" },
     limit = 1,
     message = "Only one of filed1 or field2 must be provided"
 )
 @LimitNonNullGroup(
     fields = { "field3", "field4" },
     limit = 2,
     message = "Both filed3 and filed3 must be provided"
 )
 public class MyObject {
     private String field1;
     private String field2;
     private String field3;
     private String field4;
 }
 

Validation Rule:

• Passes if limit N of the specified fields are non-null
• Fails if fewer or more than N are non-null

This annotation must be applied at the class level. It uses reflection to count how many of the specified fields are non-null during validation.

Author:

ChatGPT

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static @interface	LimitNonNullGroup.List	Container annotation for repeatable use of LimitNonNullGroup.

Required Element Summary

Required Elements

Modifier and Type	Required Element	Description
String[]	fields

Optional Element Summary

Optional Elements

Modifier and Type	Optional Element	Description
Class<?>[]	groups
int	limit
String	message
Class<? extends jakarta.validation.Payload>[]	payload

Element Details

message

String message

Default:

"Exactly one of the specified fields must be non-null"

groups

Class<?>[] groups

Default:

{}

payload

Class<? extends jakarta.validation.Payload>[] payload

Default:

{}

fields

String[] fields

limit

int limit

Default:

1