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@YamlConfig Annotation

The @YamlConfig annotation is used to apply YAML serializer and parser configuration annotations to REST resources, methods, and other contexts.

When to use it​

Use @YamlConfig to set YAML options once on a class, method or REST resource, instead of calling builder methods on every serializer. In a plain program you apply it by passing the annotated class to a builder's applyAnnotations; in a REST resource Juneau applies it for you.

Example​

import org.apache.juneau.marshall.*;
import org.apache.juneau.marshall.yaml.*;

public class YamlAnnotationExample {

    @Marshalled(typeName="person")
    public static class Person {
        public String name = "John Smith";
    }

    public static class Holder {
        public Object item = new Person();
    }

    // The annotation turns on _type properties for any serializer that applies this class.
    @YamlConfig(addBeanTypes="true")
    public static class Config {}

    public static void main(String[] args) throws Exception {
        YamlSerializer plain = YamlSerializer.create()
            .beanDictionary(Person.class)
            .build();
        YamlSerializer typed = YamlSerializer.create()
            .beanDictionary(Person.class)
            .applyAnnotations(Config.class)
            .build();

        System.out.println(plain.write(new Holder()));
        System.out.println(typed.write(new Holder()));
    }
}

The first serializer writes name: John Smith under item; the second adds _type: person there, because the declared type Object hides the runtime type.

Options​

ElementEffect
addBeanTypesAdd _type properties to beans whose runtime type differs from the declared type. A true or false string, resolved through SVL.
rankOverrides the default ordering when several config annotations apply to the same target.

REST Integration​

YAML support can be added to REST resources using the BasicYamlConfig interface or by including the YAML serializer and parser in BasicUniversalConfig:

// YAML-only REST resource
@Rest
class MyYamlResource extends RestServlet implements BasicYamlConfig {

    @RestGet("/person/{id}")
    public Person getPerson(@Path int id) {
        return findPerson(id);
    }
}

// Universal resource supporting JSON, XML, HTML, UON, and YAML
@Rest
class MyUniversalResource extends RestServlet implements BasicUniversalConfig {

    @RestGet("/person/{id}")
    public Person getPerson(@Path int id) {
        return findPerson(id);
    }
}

Custom Configuration​

You can configure the YAML serializer and parser through annotation or programmatic builders:

@Rest(
    serializers = YamlSerializer.class,
    parsers = YamlParser.class,
    defaultAccept = "application/yaml"
)
class MyResource extends RestServlet {
    // ...
}

See also​