juneau-core/juneau-marshall/src/main/java/org/apache/juneau/http/annotation/ResponseBody.java

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package org.apache.juneau.http.annotation;

import static java.lang.annotation.ElementType.*;
import static java.lang.annotation.RetentionPolicy.*;

import java.io.*;
import java.lang.annotation.*;

/**
 * REST response body annotation.
 *
 * <p>
 * Annotation used to denote an HTTP response body.
 *
 * <p>
 * Can be used in the following locations:
 * <ul>
 * 	<li>Methods and return types of server-side and client-side <ja>@Response</ja>-annotated interfaces.
 * </ul>
 *
 *
 * <h5 class='topic'>Public methods of <ja>@Response</ja>-annotated methods</h5>
 * <p>
 * On {@link Response @Response}-annotated classes, this method can be used to denote a POJO to use as the response.
 *
 * <p>
 * The method must be public and be one of the following:
 * <ul>
 * 	<li>A public no-arg method with a POJO return type.
 * 	<li>A public one-arg method with a <jk>void</jk> return type that takes in a {@link Reader} or {@link OutputStream}.
 * </ul>
 *
 * <h5 class='section'>Example:</h5>
 * <p class='bcode w800'>
 * 	<ja>@RestMethod</ja>
 * 	<jk>public</jk> AddPetSuccess addPet() {
 * 		<jsm>addPet</jsm>(pet);
 * 		<jk>return new</jk> AddPetSuccess(...);
 * 	}
 * </p>
 *
 * <h5 class='figure'>Example:</h5>
 * <p class='bcode w800'>
 * 	<ja>@Response</ja>
 * 	<jk>public class</jk> AddPetSuccess {
 *
 * 		<ja>@ResponseBody</ja>
 * 		<jk>public</jk> Pet getPet() {...}
 * 	}
 * </p>
 *
 * <h5 class='section'>Example:</h5>
 * <p class='bcode w800'>
 * 	<ja>@Response</ja>
 * 	<jk>public class</jk> MyCustomJsonResponse {
 *
 * 		<ja>@ResponseHeader</ja>(<js>"Content-Type"</js>)
 * 		<jk>public</jk> String getContentType() {
 * 			<jk>return</jk> <js>"application/json"</js>;
 * 		}
 *
 * 		<ja>@ResponseBody</ja>
 * 		<jk>public void</jk> writeTo(Writer out) {
 * 			out.write(<js>"{'foo':'bar'}"</js>);
 * 		}
 * 	}
 * </p>
 *
 * <h5 class='topic'>Methods and return types of server-side and client-side @Response-annotated interfaces</h5>
 *
 * <ul class='seealso'>
 * 	<li class='link'>{@doc juneau-rest-server.HttpPartAnnotations.Response}
 * 	<li class='link'>{@doc juneau-rest-client.RestProxies.Response}
 * </ul>
 */
@Documented
@Target(METHOD)
@Retention(RUNTIME)
@Inherited
public @interface ResponseBody {}