Directives

Custom Directives

You can add your own GraphQL Directives by writing a corresponding Java Annotation and annotate it as @Directive, e.g.:

@Directive(on = { OBJECT, INTERFACE })
@Description("Just a test")
@Retention(RUNTIME)
public @interface MyDirective {
}

Directives can be repeatable, see the @Key annotation for an example.

Directives generated from Bean Validation annotations

If your project uses Bean Validation to validate fields on input types and operation arguments, and you enable inclusion of directives in the schema (by setting smallrye.graphql.schema.includeDirectives=true), then constraints decoded from annotations will be added to your schema as directives. This is currently only supported for some built-in constraints (annotations from the javax.validation.constraints package), and custom constraints aren't supported at all.

Each bean validation annotation is mapped to a single @constraint directive. The directive is declared as repeatable, so if you have multiple constraints on an input field, the field will contain multiple @constraint directives. The following table describes the mapping between BV annotations and @constraint directives (all currently supported BV annotations are listed here):

BV annotation	GraphQL directive
@Size(MIN, MAX)	@constraint(minLength=MIN, maxLength=MAX)
@Email	@constraint(format='email')
@Max	@constraint(max=VALUE)
@Min	@constraint(min=VALUE)
@Pattern(REGEXP)	@constraint(pattern=REGEXP)

Note: The @NotNull annotation does not map to a directive, instead it makes the GraphQL type non-nullable.

Constraints will only appear on fields of input types and operation arguments.