package org.infinispan.notifications.cachelistener.annotation;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
import org.infinispan.distribution.DistributionManager;
import org.infinispan.distribution.ch.ConsistentHash;
import org.infinispan.notifications.IncorrectListenerException;
import org.infinispan.notifications.cachelistener.event.Event;
import org.infinispan.notifications.cachelistener.event.TopologyChangedEvent;
/**
* This annotation should be used on methods that need to be notified when the {@link ConsistentHash} implementation
* in use by the {@link DistributionManager} changes due to a change in cluster topology. This is only fired
* in a {@link Configuration.CacheMode#DIST_SYNC} or {@link Configuration.CacheMode#DIST_ASYNC} configured cache.
* <p/>
* Methods annotated with this annotation should accept a single parameter, a {@link TopologyChangedEvent} otherwise a
* {@link IncorrectListenerException} will be thrown when registering your listener.
* <p/>
* Note that methods marked with this annotation will be fired <i>before</i> and <i>after</i> the updated {@link ConsistentHash}
* is installed, i.e., your method will be called twice, with {@link Event#isPre()} being set to <tt>true</tt> as well
* as <tt>false</tt>.
* <p/>
*
* @author Manik Surtani
* @see org.infinispan.notifications.Listener
* @since 5.0
*/
// ensure this annotation is available at runtime.
@Retention(RetentionPolicy.RUNTIME)
// ensure that this annotation is applied to classes.
@Target(ElementType.METHOD)
public @interface TopologyChanged {
}