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package org.glassfish.jersey.spi;
import java.util.concurrent.ScheduledExecutorService;
/**
* An extension contract for providing pluggable scheduled executor service providers to be used by
* Jersey client or server runtime whenever a specific scheduler is needed to schedule execution of a
* Jersey runtime processing task.
* <p>
* This mechanism allows Jersey to run in environments that have specific thread management and provisioning requirements,
* such as application servers, cloud environments etc.
* Dedicated Jersey extension modules or applications running in such environment may provide a custom
* implementation of the {@code ScheduledExecutorServiceProvider} interface to customize the default
* Jersey runtime thread management & provisioning strategy in order to comply with the threading requirements,
* models and policies specific to each particular environment.
* </p>
* Jersey runtime expects that a concrete scheduled executor service provider implementation class is annotated with a
* {@link javax.inject.Qualifier qualifier} annotation. This qualifier is then used to createAndInitialize a qualified injection point
* for injecting the scheduled executor service instance provided by the annotated provider. {@link javax.inject.Named Named}
* providers are also supported. For example:
* </p>
* <pre>
* @Named("my-scheduler")
* public MySchedulerProvider implements ScheduledExecutorServiceProvider {
* ...
* }
*
* ...
*
* // Injecting ScheduledExecutorService provided by the MySchedulerProvider
* @Inject @Named("my-scheduler") ScheduledExecutorService myScheduler;
* </pre>
*
* @author Marek Potociar (marek.potociar at oracle.com)
* @see ExecutorServiceProvider
* @see ScheduledThreadPoolExecutorProvider
* @since 2.18
*/
@Contract
public interface ScheduledExecutorServiceProvider extends ExecutorServiceProvider {
/**
* Get a scheduled executor service to be used by Jersey client or server runtime to schedule execution of
* specific tasks.
* <p>
* <p>
* This method is <em>usually</em> invoked just once at either Jersey client or server application runtime initialization,
* it <em>may</em> however be invoked multiple times. Once the instance of the provided scheduled executor service is not
* needed anymore by Jersey application runtime, it will be {@link #dispose disposed}.
* This typically happens in one of the following situations:
* </p>
* <ul>
* <li>Jersey client instance is closed (client runtime is shut down).</li>
* <li>Jersey container running a server-side Jersey application is shut down.</li>
* <li>Jersey server-side application is un-deployed.</li>
* </ul>
*
* @return a scheduled executor service. Must not return {@code null}.
*/
@Override
public ScheduledExecutorService getExecutorService();
}