org.apache.juneau.annotation

Annotation Type Swap

@Documented
 @Target(value={TYPE,ANNOTATION_TYPE,FIELD,METHOD})
 @Retention(value=RUNTIME)
 @Inherited
public @interface Swap

Associates PojoSwap and Surrogate classes with POJOs and bean properties.

This annotation can be used in the following locations:

• Classes.
• Bean getters/setters/fields.
• Inside the @Swaps annotation.

See Also:

• Overview > juneau-marshall > Transforms > @Swap Annotation

Optional Element Summary

Optional Elements

Modifier and Type	Optional Element and Description
Class<?>	impl The PojoSwap and Surrogate class.
String[]	mediaTypes Identifies the media types that this swap is applicable for.
String	template Identifies a template string along with this swap.
Class<?>	value The PojoSwap and Surrogate class.

Element Detail

impl

public abstract Class<?> impl

The PojoSwap and Surrogate class.

A synonym for value().

Default:

org.apache.juneau.annotation.Null.class

mediaTypes

public abstract String[] mediaTypes

Identifies the media types that this swap is applicable for.

In the following example, the swap is only invoked by the JSON serializer:

@Swap(impl=ToStringSwap.class, mediaTypes="*/json") public class MyBean { ... } public class ToStringSwap extends PojoSwap<Object,String> { public String swap(BeanSession session, Object o) throws Exception { return o.toString(); } }

See Also:

• Overview > juneau-marshall > Transforms > Per-media-type PojoSwaps

Default:

{}

template

public abstract String template

Identifies a template string along with this swap.

Template strings are arbitrary strings associated with swaps that help provide additional context information for the swap class. They're called 'templates' because their primary purpose is for providing template names, such as Apache FreeMarker template names.

The following is an example of a templated swap class used to serialize POJOs to HTML using FreeMarker:

// Our templated swap class. public class FreeMarkerSwap extends PojoSwap<Object,Reader> { public MediaType[] forMediaTypes() { return MediaType.forStrings("*/html"); } public Reader swap(BeanSession session, Object o, String template) throws Exception { return getFreeMarkerReader(template, o); // Some method that creates raw HTML. } }

@Swap(impl=FreeMarkerSwap.class, template="MyPojo.div.ftl") public class MyPojo {}

See Also:

• Overview > juneau-marshall > Transforms > Templated Swaps

Default:

""

value

public abstract Class<?> value

The PojoSwap and Surrogate class.

A synonym for impl().

Default:

org.apache.juneau.annotation.Null.class