javax.ws.rs.container.Suspended Maven / Gradle / Ivy
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/*
* Copyright (c) 2012, 2017 Oracle and/or its affiliates. All rights reserved.
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License v. 2.0, which is available at
* http://www.eclipse.org/legal/epl-2.0.
*
* This Source Code may also be made available under the following Secondary
* Licenses when the conditions for such availability set forth in the
* Eclipse Public License v. 2.0 are satisfied: GNU General Public License,
* version 2 with the GNU Classpath Exception, which is available at
* https://www.gnu.org/software/classpath/license.html.
*
* SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
*/
package javax.ws.rs.container;
import java.lang.annotation.Documented;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
import java.util.concurrent.TimeUnit;
/**
* Inject a suspended {@link AsyncResponse} into a parameter of an invoked
* JAX-RS {@link javax.ws.rs.HttpMethod resource or sub-resource method}.
*
* The injected {@code AsyncResponse} instance is bound to the processing
* of the active request and can be used to resume the request processing when
* a response is available.
*
* By default there is {@link AsyncResponse#NO_TIMEOUT no suspend timeout set} and
* the asynchronous response is suspended indefinitely. The suspend timeout as well
* as a custom {@link TimeoutHandler timeout handler} can be specified programmatically
* using the {@link AsyncResponse#setTimeout(long, TimeUnit)} and
* {@link AsyncResponse#setTimeoutHandler(TimeoutHandler)} methods. For example:
*
*
* @Stateless
* @Path("/")
* public class MyEjbResource {
* …
* @GET
* @Asynchronous
* public void longRunningOperation(@Suspended AsyncResponse ar) {
* ar.setTimeoutHandler(customHandler);
* ar.setTimeout(10, TimeUnit.SECONDS);
* final String result = executeLongRunningOperation();
* ar.resume(result);
* }
*
* private String executeLongRunningOperation() { … }
* }
*
*
* A resource or sub-resource method that injects a suspended instance of an
* {@code AsyncResponse} using the {@code @Suspended} annotation is expected
* be declared to return {@code void} type. Methods that inject asynchronous
* response instance using the {@code @Suspended} annotation and declare a
* return type other than {@code void} MUST be detected by the JAX-RS runtime and
* a warning message MUST be logged. Any response value returned from such resource
* or sub-resource method MUST be ignored by the framework:
*
*
* @Path("/messages/next")
* public class MessagingResource {
* …
* @GET
* public String readMessage(@Suspended AsyncResponse ar) {
* suspended.put(ar);
* return "This response will be ignored.";
* }
* …
* }
*
*
* @author Marek Potociar
* @since 2.0
*/
@Target({ElementType.PARAMETER})
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface Suspended {
}