Java tutorial
/* * Copyright 2016-present Open Networking Laboratory * * 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.onosproject.cluster.impl; import static org.slf4j.LoggerFactory.getLogger; import java.util.Map; import org.apache.felix.scr.annotations.Activate; import org.apache.felix.scr.annotations.Component; import org.apache.felix.scr.annotations.Deactivate; import org.apache.felix.scr.annotations.Reference; import org.apache.felix.scr.annotations.ReferenceCardinality; import org.apache.felix.scr.annotations.Service; import org.onosproject.cluster.ClusterService; import org.onosproject.cluster.Leadership; import org.onosproject.cluster.LeadershipAdminService; import org.onosproject.cluster.LeadershipEvent; import org.onosproject.cluster.LeadershipEventListener; import org.onosproject.cluster.LeadershipService; import org.onosproject.cluster.LeadershipStore; import org.onosproject.cluster.LeadershipStoreDelegate; import org.onosproject.cluster.NodeId; import org.onosproject.event.AbstractListenerManager; import org.slf4j.Logger; import com.google.common.collect.Maps; /** * Implementation of {@link LeadershipService} and {@link LeadershipAdminService}. */ @Component(immediate = true) @Service public class LeadershipManager extends AbstractListenerManager<LeadershipEvent, LeadershipEventListener> implements LeadershipService, LeadershipAdminService { private final Logger log = getLogger(getClass()); private LeadershipStoreDelegate delegate = this::post; @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY) protected ClusterService clusterService; @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY) protected LeadershipStore store; private NodeId localNodeId; @Activate public void activate() { localNodeId = clusterService.getLocalNode().id(); store.setDelegate(delegate); eventDispatcher.addSink(LeadershipEvent.class, listenerRegistry); log.info("Started"); } @Deactivate public void deactivate() { Maps.filterValues(store.getLeaderships(), v -> v.candidates().contains(localNodeId)).keySet() .forEach(this::withdraw); store.unsetDelegate(delegate); eventDispatcher.removeSink(LeadershipEvent.class); log.info("Stopped"); } @Override public Leadership getLeadership(String topic) { return store.getLeadership(topic); } @Override public Leadership runForLeadership(String topic) { return store.addRegistration(topic); } @Override public void withdraw(String topic) { store.removeRegistration(topic); } @Override public Map<String, Leadership> getLeaderBoard() { return store.getLeaderships(); } @Override public boolean transferLeadership(String topic, NodeId to) { return store.moveLeadership(topic, to); } @Override public void unregister(NodeId nodeId) { store.removeRegistration(nodeId); } @Override public boolean promoteToTopOfCandidateList(String topic, NodeId nodeId) { return store.makeTopCandidate(topic, nodeId); } }