Interface Validator<T, A extends Annotation>

All Known Implementing Classes:

NotPermissionValidator, PermissionValidator

Functional Interface:

This is a functional interface and can therefore be used as the assignment target for a lambda expression or method reference.

@FunctionalInterface
public interface Validator<T, A extends Annotation>

Validators check if a command option fulfills the given constraint.

Register them at the [JDACBuilder#validator(Class, Validator)()] or use the @Implementation.Validator annotation of the guice extension.

Example

@Target(ElementType.PARAMETER)
@Retention(RetentionPolicy.RUNTIME)
@Constraint(String.class)
public @interface MaxString {
    int value();
}

public class MaxStringLengthValidator implements Validator<String, MaxString> {

    @Override
    public boolean apply(String argument, MaxString annotation, Context ctx) {
        if (argument.length() < maxString.value()) {
            context.fail("The given String is too long");
        }
    }
}

Perm and NotPerm Validators localization

The fail messages of the two default Validators for Perm and NotPerm can be localized with the localization keys validator.noperm.fail and validator.perm.fail respectively.

See Also:

• Constraint

Nested Class Summary

Nested Classes

Modifier and Type	Interface	Description
static class	Validator.Context	This context provides access to the InvocationContext of this interaction and has some utility methods useful for error messages.

Method Summary

Modifier and Type	Method	Description
void	apply(T argument, A annotation, Validator.Context context)	Validates an argument.

Method Details

apply

void apply(T argument,
 A annotation,
 Validator.Context context)

Validates an argument.

If the parameter doesn't pass the validation, you can cancel this interaction by invoking Validator.Context.fail(String, Entry...) with an appropriated error message.

Parameters:

argument - the argument to validate

annotation - the corresponding annotation

context - the corresponding InvocationContext