org.osgi.service.coordinator.Participant Maven / Gradle / Ivy
/*
* Copyright (c) OSGi Alliance (2010, 2013). All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.osgi.service.coordinator;
/**
* A Participant participates in a Coordination.
*
*
* A Participant can participate in a Coordination by
* {@link Coordination#addParticipant(Participant) registering} itself with the
* Coordination. After successfully registering itself, the Participant is
* notified when the Coordination is terminated.
*
*
* If a Coordination terminates {@link Coordination#end() normally}, then all
* registered Participants are notified on their {@link #ended(Coordination)}
* method. If the Coordination terminates as a
* {@link Coordination#fail(Throwable) failure}, then all registered
* Participants are notified on their {@link #failed(Coordination)} method.
*
*
* Participants are required to be thread safe as notification can be made on
* any thread.
*
*
* A Participant can only be registered with a single active Coordination at a
* time. If a Participant is already registered with an active Coordination,
* attempts to register the Participation with another active Coordination will
* block until the Coordination the Participant is registered with terminates.
* Notice that in edge cases the notification to the Participant that the
* Coordination has terminated can happen before the registration method
* returns.
*
* @ThreadSafe
* @author $Id: 6bef92f858270876b0d23bfb8b797b970bca2a27 $
*/
public interface Participant {
/**
* Notification that a Coordination has terminated
* {@link Coordination#end() normally}.
*
*
* This Participant should finalize any work associated with the specified
* Coordination.
*
* @param coordination The Coordination that has terminated normally.
* @throws Exception If this Participant throws an exception, the
* {@link Coordinator} service should log the exception. The
* {@link Coordination#end()} method which is notifying this
* Participant must continue notification of other registered
* Participants. When this is completed, the
* {@link Coordination#end()} method must throw a
* CoordinationException of type
* {@link CoordinationException#PARTIALLY_ENDED}.
*/
void ended(Coordination coordination) throws Exception;
/**
* Notification that a Coordination has terminated as a
* {@link Coordination#fail(Throwable) failure}.
*
*
* This Participant should discard any work associated with the specified
* Coordination.
*
* @param coordination The Coordination that has terminated as a failure.
* @throws Exception If this Participant throws an exception, the
* {@link Coordinator} service should log the exception. The
* {@link Coordination#fail(Throwable)} method which is notifying
* this Participant must continue notification of other registered
* Participants.
*/
void failed(Coordination coordination) throws Exception;
}